Category Archives: Ratings

Citrus Leaf Blotch Virus

    California Pest Rating for
Citrus leaf blotch virus
Pest Rating: B

 


PEST RATING PROFILE

Initiating Event:

On February 26, 2018, Dr. G. Vidalakis, University of California, Director, Citrus Clonal Protection Program, informed CDFA of his detection of Citrus leaf blotch virus (CLBV) from a Bearss Lime tree at a residence in Los Angeles County.  Subsequently, an official sample, which comprised a total of 4 subsamples, was collected by the CDFA from the same Bearss Lime tree and sent to the CDFA Plant Pathology Laboratory for diagnosis. On February 27, 2018, Tongyan Tian, CDFA Plant Pathologist, detected Citrus leaf blotch virus from all four subsamples using RT-qPCR and further confirmed the identity of the pathogen by conventional RT-PCR and sequencing. A temporary Q rating was assigned to the pathogen.  The status, risk and consequences of introduction of CLBV to California are assessed and a pest permanent pest rating is proposed herein.

History & Status:

Background: In 1968, Dweet mottle virus (DMV) was initially detected and reported from Riverside, California, during re-indexing of a candidate Cleopatra mandarin variety (C. reticulata) on ‘Dweet’ tangor at the University of California Riverside Citrus Variety Improvement Program, the forerunner of the present Citrus Clonal Protection Program (CCPP).  The candidate mandarin variety had been introduced from Florida into the Program at Riverside.  The virus produced leaf chlorotic blotching symptoms that resembled, but were distinct from, symptoms produced by psorosis virus and Citrus concave gum virus.  It also produced a mild exocortis reaction in Etrog citron.  The parent tree did not show symptoms of damage caused by any known virus and the trunk appeared normal without any signs of stem pitting or bark discoloration, although small fruit, twig dieback and little new growth were apparent.  Since the virus produced symptoms only in ‘Dweet’, it was named Dweet mottle virus (Roistacher & Blue, 1968). However, Dweet mottle virus was not reported from any commercial citrus production sites nor was it observed to produce any economic losses and was detected only once after 1963 in the CCPP indexing program (Krueger et al., 2012).

Then in 1984, at the Citrus Variety Improvement Program in Spain, Navarro and other scientists reported a new graft transmissible disease that caused a bud-union incompatibility between ‘Nagami’ kumquat and ‘Troyer’ citrange rootstock. The ‘Nagami’ kumquat had been introduced from Corsica, France.  In addition to bud-union incompatibility, the presumptive virus involved caused vein clearing in certain citrus species and stem pitting in Etrog citron.  However, after shoot-tip grafting, some plants produced were compatible with Troyer, but still caused stem pitting in Etrog citron, thereby, indicating the involvement of more than one virus (Navarro et al., 1984). Galipienso et al., 2000, gave further evidence of the involvement of more than one virus by demonstrating bud union crease in certain citrus species but not others when propagated on ‘Troyer’ citrange. However, chlorotic blotching in ‘Dweet’ tangor, like those induced by DMV, and stem pitting in Etrog citron were produced by all sources of the virus.  In 2001-02, the causal agent in “Nagami’ kumquat was partially purified and characterized and given the candidate name, Citrus leaf blotch virus (CLBV) (Galipienso et al., 2001; Vives et al., 2001, 2002).  Furthermore, these researchers detected CLBV in different citrus varieties from Japan, New South Wales (Australia), Spain, and Florida, usually associated with abnormal bud union on citrange or citrumelo. Comparison of 14 CLBV isolates from Spain, Japan, USA, France and Australia showed low genetic diversity (Vives et al., 2002).  Low rates of seed transmission were demonstrated in three citrus varieties or hybrids (Guerri et al., 2004).     A few years later, Vives et al., (2005) conducted partial sequence analysis to show that Dweet mottle virus from California had over 96% sequence (high) homology with citrus leaf blotch virus from Spain and therefore, suggested that DMV may be caused by CLBV.  Both viruses induce mottling in ‘Dweet’ tangor and stem pitting in ‘Etrog’ citron and that, besides CLBV, a different pathogen causing bud-union crease and vein clearing may be present in ‘Nagami’ kumquat sources but not in DMV from California source.  This was further demonstrated by Vives et al., (2008a) by the development of full-genome cDNA clones of CLBV that caused systemic infection in agro-inoculated herbaceous and citrus host plants and induced chlorotic blotching in ‘Dweet’ tangor and stem pitting in Etrog citron, but not vein clearing in Pineapple sweet orange or bud union crease on trifoliate rootstocks.  Then in 2010, Hajeri and other researchers at the University of California, Riverside, and the USDA ARS National Clonal Germplasm Repository for Citrus and Dates (NCGRCD), Riverside, determined the complete nucleotide sequence of DMV and with phylogenetic analysis showed that DMV is an isolate of CLBV, and not a distinct species, within the genus Citrivirus.

In California, the seed transmissibility of citrus leaf blotch virus caused concern to the citrus nursery industry.  Consequently, Kreuger et al. (2012) reported that all citrus trees at CCPP and NCGRCD were tested for the presence of the virus using RT-PCR with local DMV positives and a CLBV positive from Florida as positive controls. The virus was not detected in the tested trees.  Furthermore, they failed to detect it during surveys of field trees exhibiting bud union abnormalities for the presence of specific pathogens and therefore, while the overall status of CLBV in California is presently unknown, they believe that this virus if present at all, is only at a low incidence.  This is because the close identity of CLBV and DMV has likely prevented CLBV from becoming introduced into California.  All introductions of new citrus germplasm are indexed into ‘Dweet’ tangor as well as other indicator species at CCPP and NCGRCD. Reaction of CLBV in ‘Dweet’ tangor would enable detection of this virus, even if the actual identity of the virus was not known at the time of indexing. Detection of positives or even misidentifications would have been eliminated by thermal therapy or shoot-tip grafting before release (Kreuger et al., 2005, 2012).

Citrus leaf blotch virus has been reported in China, Corsica (France), Cuba, Italy, Japan, New South Wales (Australia), New Zealand, Spain, Florida, Arkansas, Oregon, and California (USA).  In Arkansas and Oregon, the virus was found in peony plants showing stunting and gnarled irregularities, however, since the virus was found in both symptomatic and asymptomatic material, it could not be associated with the disease and its role in peony health is currently unknown.  Nonetheless, CLBV may easily move between propagation cycles via mechanical and seed transmission of clonally propagated peony plants (Gress et al., 2017).

Citrus leaf blotch virus not only causes symptomless infection in most citrus but also, is unevenly distributed within an infected plant, thereby presenting a possible challenge for its detection. In greenhouse studies, Vives et al. (2002) detected CLBV consistently in young leaves of infected ‘Nagami’ kumquat, ‘Owari’ Satsuma, Navelina and Navel oranges, however, detection in old leaves of other citrus species (Eureka lemon, Marsh grapefruit and Nules Clementine) was not consistent, particularly in Pineapple sweet orange.  Detection of the virus in field trees was even less consistent, and not detected in neighbor trees showing similar symptoms possibly due to low titer or uneven distribution of the virus in the plant.

HostsCitrus spp., including C. sinensis, C. limon, C. unshiu, C. paradisi, Poncirus trifoliata, P. trifoliata x C. sinensis (Harper et al., 2008), C. medica (Etrog citrus), C. reticulata x C. sinensis (‘Dweet’ tangor) (Roistacher & Blue, 1968), Fortunella margarita (kumquat “Nagami’) (Navarro et al., 1984), Prunus avium cv. Red-lamp (sweet cherry) (Wang et al., 2016), Actinidia sp. (kiwifruit) (Zhu et al., 2016), Paeonia lactiflora (peony) (Gress et al., 2017).  Experimental hosts include Nicotiana cavicola (Guardo et al., 2009), N. occidentalis and N. benthamiana (Vives et al., 2008b).

Symptoms: Citrus leaf blotch virus causes symptomless infection in most citrus species and cultivars (Vives et al., 2008a).  However, CLBV (and the isolate, DMV) induce chlorotic blotching or mottling in ‘Dweet’ tangor and stem pitting ‘Etrog’ citron. Although CLBV does not induce bud union crease on trifoliate rootstock (Vives et al., 2008a), it has been found to be usually associated with abnormal bud union on citrange or citrumelo rootstock. A different pathogen or interaction of CLBV with a different pathogen is likely the cause of bud union crease and vein clearing symptoms (Vives et al., 2005).

Damage Potential: Citrus leaf blotch virus causes chlorotic leaf blotching in ‘Dweet’ tangor and stem pitting in Etrog citron.  Although it does not induce bud union crease in several citrus species it is usually associated with bud union crease symptoms in citrange and citrumelo rootstocks and therefore, an interaction between CLBV and other agent(s) cannot be ruled out.  There are no reports of yield losses due to CLBV and the virus can cause symptomless infections in most citrus species and cultivars. In California, CLBV (aka DMV) is a regulated pathogen and its distribution is unknown or at best likely to be of low incidence. CLBV (aka DMV) was not reported from any commercial citrus production sites in California nor was it observed to produce any economic losses (Krueger et al., 2012).  However, in certain scion-rootstock combinations using ‘Dweet’ tangor and Etrog citron rootstocks there may be a potential for disease development due to CLBV.

TransmissionCitrus leaf blotch virus is transmitted in citrus by grafting and seed.  CLBV dispersal occurs primarily by propagation of infected buds.  Low rates of seed transmission in at least three citrus species and hybrid, ‘Troyer’ citrange (Citrus sinensis x Poncirus trifoliata), ‘Nagami’ kumquat (Fortunella margarita) and sour orange (C. aurantium), has been demonstrated (Guerri et al., 2004).  Also, CLBV has been mechanically transmitted to Nicotiana cavicola (Guardo et al., 2009), by sap inoculation to N. occidentalis and N. benthamiana (Vives et al., 2008b), and transmitted from citrus to citrus by contaminated knife blades (Roistacher et al., 1980).  The virus is not transmitted by vectors (Galipienso et al., 2000).

Worldwide Distribution: Asia: China, Japan; Europe: Italy, Spain; North America: USA, Cuba; Oceania: New South Wales (Australia), New Zealand (Cao et al., 2017; Gress et al., 2017; Guardo et al., 2007; Harper et al., 2008; Hernández-Rodríguez, 2016; Navarro et al., 1984; Roistacher & Blue, 1968; Vives et al., 2002; Wang et al., 2016).

Official Control: Citrus leaf blotch virus is on the ‘Harmful Organism’ list for Uruguay (USDA PCIT, 2018).  CLBV (aka DMV) is a regulated pathogen in California’s mandatory Citrus Nursery Stock Pest Cleanliness Program (CCR, Title 3, Division 4, Chapter 4, Subchapter 6, Section 3701).

California Distribution: The distribution in California is unknown.  If at all present, it is likely to be only at a low incidence (Kreuger et al., 2005, 2012.  See: ‘Background’).

California Interceptions: No official interceptions have been reported.

The risk Citrus leaf blotch virus would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Although the distribution of Citrus leaf blotch virus in California, is presently unknown and is likely to be only at a low incidence (Kreuger et al., 2012), if not regulated, it may be possible for the pathogen to have a widespread establishment in symptomatic and non-symptomatic infected citrus varieties in commercial citrus-growing regions of the State.

Evaluate if the pest would have suitable hosts and climate to establish in California.  Score: 3

– Low (1) Not likely to establish in California; or likely to establish in very limited areas.

– Medium (2) may be able to establish in a larger but limited part of California.

High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: The natural host range is limited primarily to Citrus  Other hosts include sweet cherry and kiwifruit reported from China and peony reported from Arkansas and Oregon. Experimental hosts include, Nicotiana cavicola, N. occidentalis and N. benthamiana.

Evaluate the host range of the pest.

Score: 1

Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

3) Pest Dispersal Potential: Citrus leaf blotch virus has high reproduction within its plant host, although unevenly distributed within infected plants. It is transmitted by grafting, seed, and mechanically. Its ability for long distance spread through infected seed render it a high rating for dispersal.

Evaluate the natural and artificial dispersal potential of the pest.

Score: 3

– Low (1) does not have high reproductive or dispersal potential.

– Medium (2) has either high reproductive or dispersal potential.

High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Citrus leaf blotch virus is a regulated pathogen under California’s mandatory Citrus Nursery Stock Pest Cleanliness Program.  Under this program any citrus stock found positive for the pathogen would be eliminated before release for commercial planting.  This pathogen causes chlorotic leaf blotching in ‘Dweet’ tangor and stem pitting in Etrog citron.  Although it does not induce bud union crease in several citrus species, it is usually associated with bud union crease symptoms in citrange and citrumelo rootstocks and therefore, an interaction between CLBV and other agent(s) cannot be ruled out.  There are no reports of yield losses due to CLBV and the virus can cause symptomless infections in most citrus species and cultivars. Researchers have stated that CLBV has not been reported from commercial citrus production sites in California nor was it observed to cause any economic losses.  If citrus stock were not regulated, it is likely that in certain scion-rootstock combinations using ‘Dweet’ tangor and Etrog citron rootstocks there may be a potential for disease development due to CLBV. In such a case, it is estimated that CLBV could lower crop yield and value and trigger the loss of markets.

Evaluate the economic impact of the pest to California using the criteria below.

Economic Impact: A, B, C

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Economic Impact Score: 3

– Low (1) causes 0 or 1 of these impacts.

– Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

5) Environmental Impact: No environmental impact is expected, however, if not regulated, CLBV may impact home/urban plantings of citrus host plants.

Evaluate the environmental impact of the pest on California using the criteria below.

Environmental Impact: E

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E.  The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Environmental Impact. Score: 2

– Low (1) causes none of the above to occur.

Medium (2) causes one of the above to occur.

– High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Citrus leaf blotch virus: 12

Add up the total score and include it here. (Score)

-Low = 5-8 points

Medium = 9-12 points

-High = 13-15 points

6) Post Entry Distribution and Survey Information: Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included. (Score)

Evaluation is (0). While the distribution of CLBV in California is currently not known, there is no evidence that it is established within the State.

Not established (0) Pest never detected in California, or known only from incursions.

-Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

-Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

-High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: (Score)

Final Score:  Score of Consequences of Introduction – Score of Post Entry Distribution and Survey Information = 12   

Uncertainty:

The in-state distribution of CLBV is not currently known.  Also, the impact of infection related to crop damage and losses is not known.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for Citrus leaf blotch virus is B.


References:

Cao, M. J., Y. -Q. Yu, X. Tian, F. Y. Y. and, R. H. Li and C. Y. Zhou.  2017.  First report of Citrus leaf blotch in lemon in China.  Plant Disease 101: 8.  https://doi.org/10.1094/PDIS-10-16-1500-PDN

Galipienso, L., L. Navarro, J. F. Ballester-Olmos, J. Pina, P. Moreno, and J. Guerri.  2000.  Host range and symptomatology of a graft transmissible pathogen causing bud union crease of citrus on trifoliate rootstocks. Plant Pathology 49: 308–314.

Galipienso, L., M. C. Vives, P. Moreno, R. G. Milne, L. Navarro and J. Guerri.  2001.  Partial characterization of Citrus leaf blotch virus, a new virus from Nagami kumquat.  Archives of Virology 146: 357–368.

Gress, J. C., S. Smith, and I. E. Tzanetakis.  2017.  First report of Citrus leaf blotch virus in peony in the U.S.A. Plant Disease 101: 637. https://doi.org/10.1094/PDIS-08-16-1218-PDN

Guardo, M., G Sorrentino, T. Marletta and A. Carusa.  2007.  First report of Citrus leaf blotch on kumquat in ItalyPlant Disease 91: 104.

Guardo, M., O. Potere, M. A. Castellano, V. Savino and A. Caruso.  2009.  A new herbaceous host for Citrus leaf blotch virus. Journal of Plant Pathology 91: 485-488.

Guardo, M., G. Sorrentino and A. Caruso.  2015.  Characterization and incidence of Citrus leaf blotch virus in Southern Italy.  12th International Citrus Congress – International Society of Citriculture. Acta Horticulturae 1065: 825-83.

Hajeri, S., C. Ramadugu, M. Keremane, G. Vidalakis and R. Lee.  2010.  Nucleotide sequence and genome organization of Dweet mottle virus and its relationship to members of the family Betaflexiviridae.  Arch Virol 15: 1523-1527.  DOI 10.1007/s00705-010-0758-1

Harper, S. J., K. M. Chooi and M. N. Pearson.  2008.  First report of Citrus leaf blotch virus in New Zealand.  Plant Disease 92: 1470.  https://doi.org/10.1094/PDIS-92-10-1470C

Hernàndez-Rodríguez, L., J. M. Pérez-Castro, G. García-García, P. Luis Ramos-González, V. Zamora-Rodríguez, Xenia Ferriol-Marchena, Inés Peña-Bárzaga and L. Batista-Le Riverend.  2016.  Citrus leaf blotch in Cuba: first report and partial molecular characterization.  Tropical Plant Pathology 41: 147. https://doi.org/10.1007/s40858-016-0078-4

Krueger, R. R., J. A. Bash and R. F. Lee.  2005.  Phytosanitary status of California citrus.  International Organization of Citrus Virologists Conference Proceedings (1957-20), 16 (16): 468-472.  https://escholarship.org/uc/item/3667q9qn

Krueger, R. R., J. A. Bash and R. F. Lee.  2012.  Dweet mottle virus and Citrus leaf blotch virus.  http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=7112

Navarro, L., J. A. Pina, J. F. Ballester-Olmos, P. Moreno and M. Cambra.  1984.  A new graft transmissible disease found in Nagami kumquat. In: Timmer L. W., and J. A. Dodds (eds) Proceedings of the 9th Conference of the International Organization of Citrus Virologists, IOCV, Riverside, pp 234–240.

Roistacher, C. N., and R. L. Blue.  1968.  A psorosis-like virus causing symptoms only on ‘Dweet’ tangor.  International Organization of Citrus Virologists Conference Proceedings (1957-2010), 4(4): 13-18.

Roistacher, C. N., E. M. Nauer and R. C. Wagner.  1980.  Transmissibility of cachexia, Dweet mottle, psorosis and infectious variegation viruses on knife blades and its prevention.  Proceedings of the 8th Conference of the International Organization of Citrus Virologists, IOCV, Riverside 1980: 225-229.

USDA PCIT.  2018. USDA Phytosanitary Certificate Issuance & Tracking System. Retrieved March 15, 2018. 3:25:54 pm CDT.  https://pcit.aphis.usda.gov/PExD/faces/ReportHarmOrgs.jsp.

Vives, M. C., L. Galipienso, L. Navarro, P. Moreno and J. Guerri.  2001.  The nucleotide sequence and genomic organization of Citrus leaf blotch virus: Candidate type species for a new virus genus.  Virology 287: 225-233.

Vives, M. C., L. Galipienso, L. Navarro, P. Moreno and J. Guerri.  2002.  Citrus leaf blotch virus: a new citrus virus associated with bud union crease on trifoliate rootstocks.  International Organization of Citrus Virologists Conference Proceedings (1957-2010), 15 (15): 205-212.

Vives, M. C., L. Rubio, L. Galipienso, L. Navarro, P. Moreno and J. Guerri.  2002.  Low genetic variation between isolates of Citrus leaf blotch virus from different host species and different geographical origins. Journal of General Virology 83: 2587–2591.

Vives M. C., J. A. Pina, J. Juarez, L. Navarro, P. Moreno and J. Guerri.  2005.  Dweet mottle disease is probably caused by Citrus leaf blotch virus. 16th Conference of the International Organization of Citrus Virologists Conference Proceedings (1957-2010), 15 (16): 251-256.

Vives, M. C., S. Martin, S. Ambros, A. Renovell, L. Navarro, J. A. Pina, P. Moreno, J. and J. Guerri.  2008a.  Development of a full-genome cDNA clone of Citrus leaf blotch virus and infection of citrus plants. Molecular Plant Pathology 9:787–797.

Vives, M. C., P. Moreno, L. Navarro and J. Guerri.  2008b.  Citrus leaf blotch virus.  In: Rao, G. P., A. Myrta and K. Ling (eds).  Characterization, Diagnosis and Management of Plant Viruses, vol. 2. Pp. 55-67.  Studium Press, Houston, TX, USA.

Wang, J., D. Zhu, Y. Tan, X. Zong, H. Wei and Q. Liu.  2016. First report of Citrus leaf blotch virus in sweet cherry.  Plant Disease 100:1027.

Zhu, Chen-xi, Wang, Guo-ping, Zheng, Ya-zhou, Yang, Zuo-kun, Wang, Li-ping, Xu, Wen-xing and N. Hong.  2016.  RT-PCR detection and sequence analysis of coat protein gene of Citrus leaf blotch virus infecting kiwifruit trees.  Acta Phytopathologica Sinica, 46 (1): 11.


Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


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Pest Rating: B

 


Posted by ls 

Banded Wood Snail | Cepaea nemoralis

BANDED WOOD SNAIL
California Pest Rating for
Banded Wood Snail  |  Cepaea nemoralis
Gastropoda: Helicidae  
Pest Rating: A

PEST RATING PROFILE
Initiating Event:

Cepaea nemoralis is frequently intercepted by CDFA. A pest rating proposal is required to support its permanent pest rating.

History & Status:

Background: Cepaea nemoralis, known as the banded wood snail, is the most common species of land snail in Europe and has been introduced to North America. This snail is commonly found in urban areas, where it inhabits gardens and abandoned lots. They feed on dead and living plant material, carrion, fungi, moss, and insects1.

          Cepaea nemoralis has a yellow, pink, or brown shell. The shell contains five dark bands. Banded wood snails are hermaphrodites, but cross fertilization occurs (each snail fertilizes the other). They often mate multiple times prior to egg-laying and can store sperm for up to 15 months. Eggs are buried in moist soil, hatching after about three weeks. The snails reach maturity in four years and may live as  long as five to nine years 1, 4.

Worldwide Distribution: Banded wood snails are distributed throughout much of Europe, extending to Poland.  This snail was introduced into North America during the nineteenth century, and it is currently found in Virginia, New York, Ontario, and Massachusetts1, 2.

Official Control: Banded wood snail is listed as a harmful organism in Canada, Israel, Japan, and Taiwan6.

California Distribution: Banded wood snails have never been found in the environment of California.

California Interceptions: Between January 2000 and August 2017, banded wood snails have been intercepted 20 times.  These interceptions include border station inspections and high risk pest exclusion activities.

The risk Cepaea nemoralis (Banded wood snail) would pose to California is evaluated below.

Consequences of Introduction:
  1. Climate/Host Interaction: Banded wood snails can feed on a variety of live and dead plants and dead animals and insects, including remains of ants, beetles, spiders, mites, springtails, and aphids. Banded wood snails may establish in larger, but limited, warm agricultural and metropolitan areas of California. It receives a Medium (2) in this category.

Evaluate if the pest would have suitable hosts and climate to establish in California:

  • Low (1) Not likely to establish in California; or likely to establish in very limited areas.
  •  Medium (2) may be able to establish in a larger but limited part of California.
  • High (3) likely to establish a widespread distribution in California.

2. Known Pest Host Range: Banded wood snails are highly polyphagous and are known to feed on a wide variety of live and dead plants and animals. It receives a High (3) in this category.

Evaluate the host range of the pest.

  • Low (1) has a very limited host range.
  • Medium (2) has a moderate host range.
  • High (3) has a wide host range.

3. Pest Dispersal Potential: Banded wood snails are obligately outcrossing hermaphrodites, with both individuals exchanging sperm during mating, and both individuals able to lay eggs afterward. On average, they lay 30-80 eggs that hatch in 15-20 days. Breeding takes place from April through October. The snail’s foot is used to create a cavity in the soil where the eggs are deposited1, 4. It receives a High (3) in this category.

Evaluate the natural and artificial dispersal potential of the pest.

  • Low (1) does not have high reproductive or dispersal potential.
  • Medium (2) has either high reproductive or dispersal potential.
  • High (3) has both high reproduction and dispersal potential

4. Economic Impact: The banded wood snail is not expected to lower crop yields. It could reduce the value of nursery stock by disfiguring plants with its presence and increase crop production costs in nurseries and orchards. The banded wood snail is a potential vector of Angiostrongylus vasorum, the French heartworm (a disease of wild and domestic canids) 3. It receives a High (3) in this category. Economic Impact: B, C, E: Environmental Score: 3

Evaluate the economic impact of the pest to California using the criteria below.

A. The pest could lower crop yield.
B. The pest could lower crop value (includes increasing crop production costs).
C. The pest could trigger the loss of markets (includes quarantines).
D. The pest could negatively change normal cultural practices.
E. The pest can vector, or is vectored, by another pestiferous organism.
F. The organism is injurious or poisonous to agriculturally important animals.
G. The organism can interfere with the delivery or supply of water for agricultural uses.

  • Low (1) causes 0 or 1 of these impacts.
  • Medium (2) causes 2 of these impacts.
  • High (3) causes 3 or more of these impacts.

5. Environmental Impact: If introduced, the banded wood snail is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes. It might trigger new chemical treatments in orchards and nurseries and by residents who find infested plants unsightly. It is not expected to significantly impact cultural practices, home/urban gardening, or ornamental plantings. It receives a Medium (2) in this category.

Environmental Impact: A, D:  Environmental Impact: Score: 2

Evaluate the environmental impact of the pest on California using the criteria below.

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.
B. The pest could directly affect threatened or endangered species.
C. The pest could impact threatened or endangered species by disrupting critical habitats.
D. The pest could trigger additional official or private treatment programs.
E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

  • Low (1) causes none of the above to occur.
  • Medium (2) causes one of the above to occur.
  • High (3) causes two or more of the above to occur.
Consequences of Introduction to California for Cepaea nemoralis(Banded wood snails): High (13) 
  • Low = 5-8 points
  • Medium = 9-12 points
  • High = 13-15 points

Post Entry Distribution and Survey Information: The banded wood snail has never been found in the environment in California and receives a Not Established (0) in this category

Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

Not established (0) Pest never detected in California, or known only from incursions.
Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).
Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.
 High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (13)

Uncertainty:

Banded wood snails are commonly intercepted. There have been no formal surveys for this snail in the state. It is therefore possible that it could be present in some locations in California. 

Conclusion and Rating Justification:

Banded wood snail is not known to occur in California and might cause significant economic and environmental impacts if it were to become established here. Currently, an “A” rating is justified.

References:
  1. Animal Diversity Web. Accessed September 7, 2017. http://animaldiversity.org/accounts/Cepaea_nemoralis/

2. Encyclopedia of Life. Accessed September 7, 2017.
http://eol.org/pages/449909/details#overview

3. G.A. Conboy. 2000. Canine Angiostrongylosis (French Heartworm). Accessed September 7, 2017.
http://www.ivis.org/advances/Parasit_Bowman/conboy_angiostrongylosis/ivis.pdf

4. Maggie Whitson. 2005. Journal of the Kentucky Academy of Science, 66(2):82-88. Accessed September 7, 2017. 
http://stoppinginvasives.com/dotAsset/e2bbc1b0-81c5-42b1-b9e4-8123952c6c02.pdf

5. Pest and Damage Record Database, California Department of Food and   Agriculture, Plant Health and Pest Prevention Services.
http://phpps.cdfa.ca.gov/user/frmLogon2.asp

6. USDA phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Accessed September 7, 2017.
https://pcit.aphis.usda.gov/pcit/


Author:

Javaid Iqbal,  California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6695; plant.health[@]cdfa.ca.gov.

Responsible Party:

Jason Leathers; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 654-1211; plant.health[@]cdfa.ca.gov.


Comment Period:*CLOSED

11/7/17 – 12/22/17


Pest Rating: A


Posted by dk

Alligatorweed | Alternanthera philoxeroides

California Pest Rating for
white flower with green leaves
Alligatorweed | Alternanthera philoxeroides
Family:  Amaranthaceae
Pest Rating: A | Proposed Seed Rating: R

PEST RATING PROFILE
Initiating Event:

There was a recent find of alligatorweed in Solano County; this is the first detection in northern California in many years.

History & Status:

Background: Alligatorweed is a perennial herb with horizontal to ascending stems to 1 m long, rooting at the nodes. The flowers are small and borne in small heads with white floral bracts. Like many aquatic emergent, it has distinctive submerged and emersed forms. The submerged form has hollow, floating, emergent and submerged stems. Terrestrial plants have solid stems. Typically, plants grow rooted in soil in shallow water and form dense, interwoven floating mats that extend over the surface of deeper water. Mats can become quite dense and nearly impenetrable. The floating mats can break away and follow currents to colonize new sites. Mats disrupt the natural ecology of a site by reducing light penetration and crowding out native species. Serious infestations can create anoxic, disease-promoting, and mosquito-breeding conditions.

Worldwide Distribution: This weed is found in wet, disturbed areas. It is also a weed of rice and sugar cane fields in tropical and subtropical regions. Native to southern Asia, alligatorweed is now found in tropical and subtropical regions around the world. It is considered an invasive species in Australia, China, New Zealand, and Thailand. Alligatorweed has been introduced throughout the southeastern United States from Virginia to Texas.

Official Control: Alligatorweed has had a CDFA rating of A as a pest in California for decades. The population in Los Angeles County has been managed intermittently over the years by the county, but it still persists.  It has official status as a weed in Alabama, Arizona, Arkansas, California, Florida, South Carolina, and Texas.

California Distribution:  Alligatorweed occurs in several southern California counties. It also has been detected in Contra Costa and Kings Counties, where it is eradicated. There was a recent find of 2 colonies in southern Solano County.

California Interceptions: Alligatorweed has been sent to CDFA by land managers.

The risk Alternanthera philoxeroides (alligatorweed) poses to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Risk is Medium (2), as the plant occurs in wetlands such as the Delta and creeks and rivers, as well as irrigation canals and watering ponds. These habitats are limited but widely distributed in California.

Evaluate if the pest would have suitable hosts and climate to establish in California:

– Low (1) Not likely to establish in California; or likely to establish in very limited areas.

Medium (2) may be able to establish in a larger but limited part of California.

– High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Most plants do not require any one host, but grow wherever ecological conditions are favorable. It receives a High (3) in this category.

Evaluate the host range of the pest.

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

High (3) has a wide host range.

3) Pest Dispersal Potential: Risk is Medium (2). Alligatorweed can spread rapidly via water movement and on boats and equipment as stem fragments. It is also grown as an aquarium plant and occasionally discarded into waterways. Seeds evidently are not produced in the United States.

Evaluate the natural and artificial dispersal potential of the pest.

– Low (1) does not have high reproductive or dispersal potential.

Medium (2) has either high reproductive or dispersal potential.

– High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Risk is High (3), as the plant can lower crop yields in rice fields, trigger state or international quarantines, and force changes in cultural practices by blocking canals. It has spread widely in the southeast, and has proven difficult to eradicate both there and in California. Its mats can improve habitat for mosquito larvae, leading to larger mosquito populations.

Evaluate the economic impact of the pest to California using the criteria below.

Economic Impact: A, C, D, E, G

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Economic Impact Score: 3

– Low (1) causes 0 or 1 of these impacts.

– Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

5) Environmental Impact: Risk is High (3) as alligatorweed could further invade the water systems of California, disrupt natural wetland communities and potentially lower biodiversity by invading wetlands. The dense growth impedes water movement, blocks the growth of native plants, and reduces available habitat for water birds and fish. Its invasion in the Delta and its tributaries could degrade habitat of rare species such as Mason’s lilaeopsis (Lilaeopsis masonii), Sacramento River Chinook salmon (Oncorhynchus tshawytscha),  and Giant garter snake (Thamnophis gigas).  Its presence would trigger additional control measures.

Evaluate the environmental impact of the pest on California using the criteria below.

Environmental Impact: A, C, D

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Environmental Impact: Score: 3

– Low (1) causes none of the above to occur.

– Medium (2) causes one of the above to occur.

High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Alternanthera philoxeroides (alligatorweed) : High (13)

-Low = 5-8 points

-Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Alligatorweed currently is known from 3-4 populations in northern and southern California. It receives a Medium (-2) in this category.

Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included:

Score: -2

-Not established (0) Pest never detected in California, or known only from incursions.

-Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

-High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (11)

Uncertainty:

Uncertainty is low, as alligatorweed has established in wetlands in California and other states. There is some uncertainty as to the actual distribution of this plant in California, as, like some other aquatic weeds, it is likely to be overlooked.

Conclusion and Rating Justification:

Conclusions of the harm(s) associated with this pest to California using all of the evidence presented above:

Proposed Rating: Despite its limited ability to disperse between watersheds, this is a potentially significant weed in California of both natural wetlands and irrigation canals. Because of its potential economic impacts, it deserves an A rating, as it has proven tenacious and is actively spreading.

References:

Baldwin, B. G., D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken, editors. 2012. The Jepson manual: vascular plants of California, second edition. University of California Press, Berkeley.

Consortium of California Herbaria. Accessed 10/3/2017:  ucjeps.berkeley.edu/consortium/

Florida Dept of Agriculture Weed of the Month: Alternanthera sessilis. Accessed 10/3/2017: http://www.freshfromflorida.com/Divisions-Offices/Plant-Industry/Plant-Industry-Publications/Weed-of-the-Month/April-2011-Alternanthera-Sessilis

Invasive Plant Atlas of the Mid-South. alligatorweed. Accessed 10/3/2017:    https://www.gri.msstate.edu/ipams/species.php?CName=Alligatorweed


Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650. plant.health[@]cdfa.ca.gov.


Comment Period: CLOSED

10/17/17 – 12/1/17*


*NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Pest Rating: A | Proposed Seed Rating: R


Posted by ls

Nutria | Myocastor coypus

California Pest Rating for
Nutria  |  Myocastor coypus
Pest Rating: A

PEST RATING PROFILE
Initiating Event

On March 30, 2017 a suspected Nutria (Myocastor coypus) was turned in to California Department of Fish and Wildlife staff in Merced County. It was confirmed by the local Department of Fish and Wildlife Services trapper.  The animal was found living in a managed wetland (duck hunting club) adjacent to the Grasslands Ecological Area in Merced County.

History & Status

Background

Nutria are large aquatic rodents that may easily be confused with the even larger North American Beaver (Castor Canadensis). Their long rat-like tail is the primary distinguishing characteristic when compared to the large paddle shaped tail of the beaver. Nutria are herbivores that may consume up to 25% of their body-weight per day, in addition they are wasteful feeders focusing on roots and tubers while discarding up to 90% of the plant matter they harvest. They may impact crops and landscape plantings in areas adjacent to water ways, damage water conveyance and storage structures, undermine roads and vector parasites and diseases to humans and livestock. Nutria are primarily nocturnal, though lack of predatory pressure or the influence of human feeding may cause an increase in daytime activity. Nutria are prolific breeders, females may have 2-3 liters per year with an average of 4-5 offspring per liter. Young become sexually active between four and six months of age. Nutria nest in dense vegetation and construct burrows for protection from cold temperatures. Burrows can range from 6-45 meters in length. Nutria have been found to cause significant damage to wetland and riparian habitats and are considered agricultural pests in many parts of the world. In the early 1900’s they were purposefully introduced in many parts of the world to supplement the trapping of furbearing animals for the fur trade. In nature, their populations are primarily limited by harsh winters, commercial trapping and large predators such as alligators or large snakes. Nutria have successfully established in brackish estuarine waters around the United States, however they are not capable of natural immigration in to California with its mountains, deserts and coastline borders.

map for predicted suitable habitat
Figure 1. Geographical extent of predicted suitable nutria habitat (based on 2003 – 2007 mechanistic model) in the contiguous United States compared to the status of nutria populations by state. (Sheffels 2013)

Worldwide Distribution

Native to South America. Nutria are a common invasive species in the Southeastern United States. Blamed for significant impacts and loss of wetlands in the Mississippi Delta as well as the Chesapeake Bay. They are widespread in the Pacific Northwest, including Oregon, Washington and Southern British Columbia. Nutria have been successfully introduced and established in every continent other than Australia and Antarctica (Chesapeake Bay Nutria Eradication Project 2016).

Official Control:

A bounty system has been used in the past in Louisiana. During the 2009-2010 trapping season the state of Louisiana paid a $5 per animal bounty on 445,963 Nutria harvested for a total of $2,229,815 (Coastwide Nutria Control Program).

When necessary USDA – Wildlife Services will control localized populations of Nutria.  In 2002 an eradication program was initiated in the state of Maryland. As of 2016 all known populations had been removed from the Delmarva Peninsula of the Chesapeake Bay in Maryland. Surveillance is currently ongoing to verify eradication (Chesapeake Bay Nutria Eradication Project 2016).

Washington State requires any trapped Nutria to be immediately euthanized and prohibits their movement (Washington Invasive Species Council 2016).

Nutria are Considered an agricultural pest in China. Nutria eradication is underway in Japan. They are known to be responsible for damage to fish ponds in Israel. Nutria are considered a pest in Western Europe but a valuable resource in Eastern Europe where fur has higher value. England initiated a trapping eradication in 1981 and declared eradication in 1989. There are numerous Nutria eradication programs in France. They are considered a pest in Germany due to damage to dams. Nutria are also considered a pest of rice production in Italy. (Carter and Leonard 2002)

California Distribution:

There are historical reports of Nutria from Elizabeth Lake, Stanislaus River and Los Angeles County. The first introduction to the United States occurred at Elizabeth Lake California in 1899 which failed due to breeding failures. The California Department of Food and Agriculture conducted an eradication program for a feral population of Nutria from the Stanislaus River during the 1960’s. Eradication was achieved by 1978 (National Wetlands Research Center 2015).

Recent modeling of Nutria distribution and climate change predict that California is highly suitable for Nutria establishment and spread. The mountainous terrain and disconnected hydrological units are the only barrier between Northern California and the Nutria infested waterways of Southern Oregon (Jarnevich et al. 2017).

California Interceptions:

One adult Nutria was trapped in a managed wetland (duck hunting club) adjacent to the Grasslands Ecological Area in Merced County. There are anecdotal reports of additional Nutria sightings from the duck club caretaker.

Consequences of Introduction

The risk Nutria would pose to California is evaluated below.

Problems associated with high Nutria populations fall into several categories: destruction of marsh habitat, destruction of water control structures such as dykes and levees, destruction of agricultural crops, and the fact that the animals can serve as repositories of a variety of diseases.

1) Climate/Host Interaction: Evaluate if the pest would have suitable hosts and climate to establish in California. Score: 3

Low (1) Not likely to establish in California; or likely to establish in very limited areas.

Medium (2) may be able to establish in a larger but limited part of California.

High (3) likely to establish a widespread distribution in California.

Recent modeling data found that the majority of California could provide suitable habitat for Nutria. High elevations and deserts being the only limiting factors. Nutria could easily move throughout the inland waterways and irrigation networks.

2) Known Pest Host Range: Evaluate the host range of the pest. Score: 2

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

Nutria are an aquatic species. Distribution would be limited to areas adjacent to waterways. Rivers, streams, estuaries and irrigation canals would all be suitable habitat. The interconnected waterways throughout the Sacramento-San Joaquin River and Delta and irrigated lands are all susceptible to Nutria establishment.

3) Pest Dispersal Potential: Evaluate the natural and artificial dispersal potential of the pest. Score: 3

Low (1) does not have high reproductive or dispersal potential.

Medium (2) has either high reproductive or dispersal potential.

High (3) has both high reproduction and dispersal potential.

Nutria could naturally disperse throughout the entire Sacramento-San Joaquin Bay-Delta watershed which covers over 75,000 square miles from Tehachapi to the Cascades Mountain Range. They could also establish around natural and man-made lakes, reservoirs, irrigation canals and other waterbodies.

4) Economic Impact: Evaluate the likely economic impacts of the pest to California using the criteria below. Score: 3

Economic Impact: A, B, E, G

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Economic Impact Score: 3

Low (1) causes 0 or 1 of these impacts.

Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

Nutria have shown to damage rice and orchards/vineyards potentially lowering crop yield and causing losses.  There is also potential for them to disrupt water delivery to crops and spread contaminants impacting food safety.  They are known to vector liver flukes and other parasites to livestock, damage water conveyance and storage infrastructure.

5) Environmental Impact: Evaluate the environmental impact of the pest on California using the criteria below. Score: 3

Environmental Impact: A, B, C, D, E

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Environmental Impact Score: 3

Low (1) causes none of the above to occur.

Medium (2) causes one of the above to occur.

High (3) causes two or more of the above to occur.

Nutria have contributed to massive wetland destruction and land loss. Nutria could feed directly on threatened or endangered wetland and riparian plants. Nutria have created eat-outs completely denuding vast areas of habitat, their burrowing activity also contributes to increased siltation of waterways which can impact fish habitat. Many areas of the United States currently have control and eradication programs targeting Nutria. In addition to being agricultural pests and damaging the environment Nutria have also impacted urban and residential landscaping, transmit parasites to animals and humans and become aggressive towards humans and pets.

Consequences of Introduction to California for Nutria:

Add up the total score and include it here. (14)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included. (-1)

Not established (0) Pest never detected in California, or known only from incursions.

Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Nutria have successfully been eradicated from California in an area close to the current location of the detections. There is only one other documented introduction in 1899 which failed to establish. There are no PDR records of other encounters in the State.

Final Score

The final score is the consequences of introduction score minus the post entry distribution and survey information score: (13)

Uncertainty

It is important to separate out uncertainty from risk. Use this section to evaluate any uncertainty associated with the introduction of the pest to California.

The three primary limiting factors of Nutria populations are harsh winters, commercial trapping and large predator populations. California has very mild winters compared to other infested areas of the world. Fur trapping is a very insignificant activity in California due to social as well as regulatory constraints and low fur prices. California does not have large populations of predators nor predators large enough to effectively take Nutria. The Southeastern U.S. has alligators and the portions of Africa that have not been impacted have many different species of large carnivores.

Conclusion and Rating Justification

Proposed rating of A.

Nutria have proven to be a significant agricultural pest in other parts of the world with similar climates and cropping systems to California. Significantly impacted crops include rice, orchards and vineyards. In addition, Nutria are a known vector of ectoparasites and diseases. Livestock are particularly susceptible to liver flukes if exposed to water soiled by Nutria excrement (Menard et al.2000). Nutria have caused extensive damage to waterways, water storage and conveyance as well as adjacent rights-of-way. Of particular concern would be the thousands of miles of earthen canal, dikes and levees comprising much of the Central Valley irrigation infrastructure (Witmer et al. 2012).

Nutria have caused extreme environmental degradation to wetlands around the United States. Their feeding behavior can produce “eat outs” which eliminate the aquatic vegetation which contains wetland and marsh soils. The subsequent erosion is extremely damaging to wetlands. In addition, this erosion combined with their burrowing activity has the potential to damage fish habitat through increased siltation. In the Chesapeake Bay estuary one of the most heavily impacted habitat types is the Spartina sp. complex similar to much of the San Francisco Bay estuary.

Due to the documented negative impacts to agriculture and the environment of Nutria establishment and the high probability of eradication in California, a rating of A is justified.


References

Carter, Jacoby, and Billy P. Leonard. “A Review of the Literature on the Worldwide Distribution, Spread of, and Efforts to Eradicate the Coypu (Myocastor coypus).” Wildlife Society Bulletin (1973-2006), vol. 30, no. 1, 2002, pp. 162–175.  www.jstor.org/stable/3784650

Chesapeake Bay Nutria Eradication Project.  “U.S. Fish and Wildlife Service Species of Concern Fact Sheet: Nutria.” (2016) Aquatic Nuisance Species Task Force.  https://www.fws.gov/chesapeakenutriaproject/

Coastwide Nutria Control Program. “Home. Nutria Control Program” (2007) Louisiana Department of Wildlife and Fisheries.  http://www.nutria.com/site9.php

Jarnevich CS, Young NE, Sheffels TR, Carter J, Sytsma MD, Talbert C “Evaluating simplistic methods to understand current distributions and forecast distribution changes under climate change scenarios: an example with coypu (Myocastor coypus).” (2017) NeoBiota 32: 107-125. https://doi.org/10.3897/neobiota.32.8884

Menard A; M. L’Hostis, G. Leray, S. Marchandeau, M. Pascal, N. Roudot, V. Michel and A. Chauvin “Inventory of Wild Rodents and Lagomorphs as Natural Hosts of Fasciola hepatica on a Farm Located in a Humid Area in Loire Atlantique (France)” (2000), Parasite, 7, 77-82 http://dx.doi.org/10.1051/parasite/2000072077

National Wetlands Research Center. “Worldwide Distribution, Spread of, and Efforts to Eradicate the Nutria (Myocastor coypus).”(2015) United Stated Geological Survey (USGS). https://www.nwrc.usgs.gov/special/nutria/namerica.htm

Pasko, Susan and Anne Marie Eich, “Species of Concern Fact Sheet: Nutria” (2011) Aquatic Nuisance Species Task Force.  https://www.anstaskforce.gov/spoc/nutria.php

Sheffels, Trevor Robert, “Status of Nutria (Myocastor coypus) Populations in the Pacific Northwest and Development of Associated Control and Management Strategies, with an Emphasis on Metropolitan Habitats” (2013).Dissertations and Thesis.Paper 665. http://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1664&context=open_access_etds

Washington Invasive Species Council. “Stop the Invasion. Nutria, Myocastor coypus” (2016) Washington Department of Fish and Wildlife. http://www.invasivespecies.wa.gov/documents/priorities/NutriaFactSheet.pdf

Witmer, Gary; Sheffels, Trevor R.; and Kendrot, Stephen R., “The Introduction, Impacts, And Management of a Large, Invasive, Aquatic Rodent in The United States” (2012). USDA National Wildlife Research Center – Staff Publications. Paper 1215. http://digitalcommons.unl.edu/icwdm_usdanwrc/1215/


Responsible Party:

David Kratville, Senior Environmental Scientist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1102, plant.health[@]cdfa.ca.gov.


Comment Period: CLOSED

July 5, 2017 – August 19, 2017


NOTE:

You must be registered and logged in to post a comment.  If you have registered and have not received the registration confirmation, please contact us at plant.health[@]cdfa.ca.gov.


Pest Rating: A


Posted by ls

Vertebrate Pests

Vertebrate pests are any species of mammal, bird, reptile, amphibian, or fish that causes damage to agricultural, natural, or industrial resources, or to any other resource, and to the public health or safety. Vertebrate pests cause millions of dollars in damage to agricultural crops, transportation infrastructure, water conveyance and restoration lands each year. Vertebrate pests threaten the public health and the environment as vectors of diseases that could be transmitted to humans, livestock and wildlife.


PEST RATINGS:

Nutria |  Myocastor coypus
Pest Rating:  A

Stemphylium solani G. F. Weber 1930

California Pest Rating for
Stemphylium solani G. F. Weber 1930
Pest Rating: A

 


PEST RATING PROFILE
Initiating Event:

On March 31, 2017, the CDFA Permits and Regulations Program requested a rating for Stemphylium solani.  Therefore, the associated risk and current status of S. solani in California are assessed here and a permanent rating is proposed.

History & Status:

Background:   Stemphylium solani is a fungal pathogen that causes Gray leaf spot disease in tomato, and Stemphylium leaf blight disease in cotton, garlic, and other hosts.  Gray leaf spot in tomato is actually caused by three species of Stemphylium, one being S. solani and the other two species: S. lycopersici (Enjoji) W. Yaman (syn. S. floridanum Hannon & G. F. Weber) and S. botryosum Wallr. f. sp. lycopersici Rotem, Y. Cohen, & I. Wahl.  Gray leaf spot is regarded one of the most destructive diseases of tomato in the southeastern United States and throughout the world wherever warm and humid conditions prevail (Jones & Pernezny, 2014).

Gray leaf spot disease has been reported from several countries worldwide including the United States (see ‘Worldwide Distribution’). In the United States, the disease was first observed in 1924 and by 1928 had spread throughout Florida causing widespread defoliation. Since then, the pathogen has been reported from several states but has never been reported from California.

Disease development:  The disease begins in infested seedbeds and transplant houses or field-transplanted seedlings, usually when the plants are in the first true-leaf stage of growth.  Cotyledons are not severely infected.   The pathogen is spread when infected seedlings are transplanted to fields.  Conidia (asexual spores) can be spread over extensive distances by wind. The teleomorph or sexual stage of S. solani is not known.  The disease is favored by warm temperatures (24-27°C) and high humidity. Spore germination and infection of plant are dependent on the presence of free moisture (dew or rain) (Jones & Pernezny, 2014).  Leaf wetness is considered more important than temperature in establishment of infection (Cerkauskas, 2005).  Stemphylium solani survives as a saprophyte on infected plant debris or on volunteer tomato, pepper, gladiolus, blue lupine, and other wild solanaceous plants.  In the southern state climates, the pathogen remains viable on tomato plants which are grown throughout the year (Jones & Pernezny, 2014).  The pathogen can be seedborne (Koike et al., 2007).

Dispersal and spread: Infected plants, seedlings, and plant debris.  Conidia may be wind-blown over extensive areas or by splashing water (Jones & Pernezny, 2014).

Hosts: Hosts of Stemphylium solani are included primarily in the plant family Solanaceae.  Numerous other plant families are also included with their associated hosts, including Amaryllidaceae (Allium sp.), Asteraceae (Lactuca sp.), and Malvaceae (Gossypium hirsutum).  Hosts include, Aegiceras corniculatum (black mangrove), Allium sativum (garlic), Aster sp. (aster), Basella rubra (Malabar spinach), Capsicum annuum (bell pepper), C. annuum var. annuum (cayenne pepper), C. frutescens (chili pepper), Carthamus sp. (distaff thistles), Cirsium sp. (thistle), Citrus sp. (citrus), Convolvulus arvensis (field bindweed), Cucumis sativus (cucumber), Dactylis glomerata (orchardgrass), Dianthus caryophyllus (carnation), Gossypium hirsutum (upland cotton), Ipomoea reptans (synonym: I. aquatica, swamp morning-glory), Kalanchoe blossfeldiana (flaming katy), Lactuca sativa (lettuce), Lupinus angustifolius (narrowleaf lupine), Lupinus sp. (lupine), Lycopersicon esculentum (synonym: L. lycopersicum, tomato), Lycopersicon sp., Pelargonium zonale (horse-shoe pelargonium), Physalis pubescens (husk tomato), Physalis sp. (groundcherry), Solanum gilo (gilo), S. lycocarpum (wolf apple), S. lycopersicum (garden tomato), S. melongena (aubergine/eggplant), S. melongena var. esculentum, S. pseudocapsicum (Jerusalem cherry), S. tuberosum (potato), Vicia faba (fava bean), Vigna sinensis (synonym: V. unguiculata, cowpea) (CABI, 2017; Farr & Rossman, 2017).

Symptoms:  Gray leaf spots or lesions are almost entirely limited to the leaf blades, but under favorable conditions, lesions may develop on petioles and on the more tender parts of growing stems.  Lesions on stems are linear and parallel to the stem.  Fruit symptoms have not been observed.  In infected tomatoes, symptoms of gray leaf spot are first exhibited as minute brownish-black specks on the lower leaves.  Randomly scattered circular to oblong spots develop on adaxial and abaxial leaf surfaces without being restricted by leaf veins.  The spots may be surrounded by a narrow yellow halo and enlarge to about 2.1 mm in diameter while individual spots on the base of leaves may enlarge to twice that size or more in diameter and occasionally coalesce, thereby, killing large portions of the leaf blade. As the spots enlarge, the centers turn gray, eventually dry, crack, and fall out.  Frequently, at this stage entire leaves conspicuously turn yellow, especially if the infection is severe, and die rapidly, turning brown before dropping from the plants.  Seedbed infections result in marked defoliation without conspicuous yellowing (Jones & Pernezny, 2014; Damicone & Brandenberger, 2015).  In garlic, early symptoms of S. solani infection were observed as white spots (1-3 mm), which enlarged to sunken purple lesions, extending until the leaves withered (Zheng et al., 2008).

Damage Potential:  Gray leaf spot almost entirely affects leaves, and defoliation can be severe reducing available photosynthetic areas of infected plants thereby, resulting in reductions in plant development, quality, and fruit yields.  In China, garlic leaf blight caused by Stemphylium solani affected over 7,000 ha of field production and reduced yields up to 70% (Zheng et al., 2010).  During 1994 and 1995, a severe epidemic of leaf blight of cotton in Brazil resulted in yield losses up to 100% in some commercial fields (Mehta, 1998). Gray leaf spot disease limited tomato production in Venezuela and Malaysia (Cadeño & Carrero, 1997; Nasehi et al., 2012).   In California, processing tomatoes are grown in the warm and dry San Joaquin and Sacramento Valleys while fresh-market tomatoes are grown in the San Joaquin Valley, Central Valley, Central and Southern Coastal regions and the Imperial Valley.  It is less likely that S. solani will be able establish under warm and dry regions of the state’s tomato production acreages, as well as under the possible use of resistant varieties, protectant fungicides and cultural management strategies.  However, for tomato and other host plants under wet and warm climates, the pathogen may be able to establish within those regions.

Worldwide Distribution: Asia: Brunei Darussalam, China, Hong, Kong, Taiwan, Thailand, Korea, Malaysia; Africa: Libya, Mauritius, Senegal, Sudan, Tanzania; Europe: Greece, Spain; North America: Canada, USA (Alabama, Florida, Georgia, Indiana, Louisiana, Maryland, Mississippi, North Carolina, New Jersey, South Carolina, Tennessee, Texas, Virginia); South America: Brazil, Honduras, Venezuela; Central America and Caribbean: Cuba; Oceania: American Samoa (CABI, 2017; Cadeño & Carrero, 1997; Farr & Rossman, 2017).

Official Control: Presently, Stemphylium solani is on the Harmful Organisms list for Peru (USDA-PCIT, 2017).

California Distribution: Stemphylium solani has not been reported from California.

California Interceptions: None reported.

The risk Stemphylium solani would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Although Stemphylium solani has a wide host range that includes several economically important agricultural crops in California as well as wild solanaceous plants, the pathogen is dependent on leaf wetness for plant infection and additionally on warm temperatures for disease development.  The disease is most severe under humid and overcast climate conditions that favor wet foliage mainly due to dew or rain.  These conditions would allow the pathogen to establish in a larger but limited part of California.

Evaluate if the pest would have suitable hosts and climate to establish in California.

Score: 2

– Low (1) Not likely to establish in California; or likely to establish in very limited areas.

Medium (2) may be able to establish in a larger but limited part of California.

– High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Stemphylium solani has a wide host range of plants included primarily in the family Solanaceae. However, numerous other plant families are also included with their associated hosts.  Economically important crops include tomato, pepper, cotton, citrus, cucumber, lettuce, garlic, eggplant and others.  Several wild solanaceous host plants could allow build-up of fungal inoculum.

Evaluate the host range of the pest.

Score: 3

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

High (3) has a wide host range.

3) Pest Dispersal Potential: Conidia are produced in abundance and readily dispersed by wind and splashing water. Also, the pathogen is spread through infected plants, seedlings, plant debris, and seed.

Evaluate the natural and artificial dispersal potential of the pest.

Score: 3

– Low (1) does not have high reproductive or dispersal potential.

– Medium (2) has either high reproductive or dispersal potential.

High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Stemphylium solani causes gray leaf spot in tomato and peppers as well as leaf blight in other hosts. Leaves are almost always entirely affected by the disease and defoliation can be severe reducing available photosynthetic areas of plants thereby, resulting in reductions in plant development, quality, and fruit yields.  If not controlled, significant reductions in crop yield and markets could occur.  Use of fungicides and cultural management practices could increase costs of crop production.

Evaluate the economic impact of the pest to California using the criteria below.

Economic Impact: A, B, C, D

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Economic Impact Score: 3

– Low (1) causes 0 or 1 of these impacts.

– Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

5) Environmental Impact:  The pathogen could significantly affect home/urban gardening of agricultural crops and ornamental hosts.

Evaluate the environmental impact of the pest on California using the criteria below.

Environmental Impact: E

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Environmental Impact Score: 2

– Low (1) causes none of the above to occur.

Medium (2) causes one of the above to occur.

– High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Stemphylium solani: High (13)

Add up the total score and include it here.

-Low = 5-8 points

-Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

Evaluation is Not establishedin California.

Score: (0)

Not established (0) Pest never detected in California, or known only from incursions.

-Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

-Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

-High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: (Score)

Final Score:  Score of Consequences of Introduction – Score of Post Entry Distribution and Survey Information = 13

Uncertainty:  

None.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for Stemphylium, solani is A.

References:

CABI, 2017.  Stemphylium solani (gray leaf spot) basic datasheet.  Crop Protection Compendium. http://www.cabi.org/cpc/datasheet/51531

Cerkauskas, R.  2005.  Tomato diseases, Gray leaf spot, Stemphylium solani, S. lycopersici found worldwide in warm climates.  AVRDC – The World Vegetable Center Fact Sheet.  AVRDC Publication 05-634.

Cadeño, L., and C. Carrero.  1997.  First report of tomato gray leaf spot caused by Stemphylium solani in the Andes Region of Venezuela.  Plant Disease 81: 1332. http://dx.doi.org/10.1094/PDIS.1997.81.11.1332B

Damicone, J. P., and L. Brandenberger.  2015.  Common diseases of tomatoes Part 1.  Diseases caused by fungi.  Oklahoma Cooperative Extension Service EPP-7625.

Farr, D. F., and A. Y. Rossman.  2017.  Fungal Databases, U. S. National Fungus Collections, ARS, USDA. Retrieved April 3, 2017, from http://nt.ars-grin.gov/fungaldatabases/

Jones, J. P., and K. L. Pernezny.  2014.  Gray Leaf Spot.  In Compendium of Tomato Disease and Pests Second Edition.  Ed. J. B. Jones, T. A. Zitter, T. M. Momol, and S. A. Miller, APS Press. The American Phytopathological Society.  29-30 p.

Koike, S. T., P. Gladders, and A. O. Paulus.  2007.  Stemphylium solani, S. lycopersici – gray leaf spot.  In Vegetables diseases a color handbook.  Academic Press, an imprint of Elsevier, Burlington, San Diego.  211-212 p.

Mehta, Y. R.  1998.  Severe outbreak of Stemphylium leaf blight, a new disease of cotton in Brazil. Plant Disease, 82: 333-336.

Nasehi, A., J. B. Kadir, M. A. Zainal Abidin, M. Y. Wong, and F. Mahmodi.  First report of tomato gray leaf spot disease caused by Stemphylium solani in Malaysia.  Plant Disease 96: 1226.  http://dx.doi.org/10.1094/PDIS-03-12-0223-PDN

USDA PCIT.  2017.  USDA Phytosanitary Certificate Issuance & Tracking System. April 3, 2017, 1:17:10 pm CDT.  https://pcit.aphis.usda.gov/PExD/faces/ReportHarmOrgs.jsp.

Zheng, L., J. B. HUANG, and T. HSIANG.  2008.  First report of leaf blight of garlic (Allium sativum) caused by Stemphylium solani in China. Plant Pathology 57: 380.

Zheng, L., L. V. Rujing, J. Huang, D. Jiang, X. Liu, and T. Hsiang.  2010.  Integrated control of garlic leaf blight caused by Stemphylium solani in China.  Canadian Journal of Plant Pathology 32: 135-145.


Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


Comment Period: CLOSED

Apr 20, 2017 – June 4, 2017


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment:
Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;

Violates agency regulations prohibiting sexual harassment or other forms of discrimination;

Violates agency regulations prohibiting workplace violence, including threats.

♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: A


Posted by ls

Pseudocercospora purpurea (Cooke) Deighton 1976

California Pest Rating for
Pseudocercospora purpurea (Cooke) Deighton 1976
Pest Rating: B

 


PEST RATING PROFILE
Initiating Event:

On November 17, 2016, USDA APHIS PPQ inquired if CDFA had conducted a pest risk assessment of the fungal pathogen, Pseudocercospora purpurea on avocados in California.  Subsequently, the risk of infestation of P. purpurea in California is evaluated and a permanent rating is herein proposed.

History & Status:

BackgroundPseudocercospora purpurea is a fungal plant pathogen that causes Pseudocercospora (Cercospora) spot (blotch) disease exhibiting leaf and fruit spot symptoms in Persea spp., including avocado (P. americana) plants. The pathogen was originally known as Cercospora purpurea. In South Africa, the disease is known as black spot or Cercospora spot and is the most serious pre-harvest disease affecting all cultivars of avocado, particularly, cv. Fuerte (Crous et al., 2000; Pohronezny et al., 1994).  The disease occurs in warm, humid and rainy climates and is found in southeastern USA, South America, northern Australia, Asia, Africa, and the Caribbean (CABI, 2016; Menge & Ploetz, 2003).  The pathogen has not been reported from California.

Disease cycle:  Initial inoculum of conidia (asexual spores) mostly comes from infected leaves.  New shoot tissues are infected wherever this disease occurs.  The pathogen penetrates host tissue either directly or through wounds. Conidia are easily detached and blown by wind often over long distances.  On landing on surfaces of a plant host, conidia require water or heavy dew to germinate and penetrate the host.  In South Africa, the pathogen remains latent for about 3 months after penetration.  Infected plants produce conidiophores (specialized hypha) that arise from the plant surface in clusters through stomata and form conidia successively.  Substomatal stroma (compact mycelial structure) may form from which conidiophores develop.  Fruit are susceptible when developed to a quarter to three-quarter of their full size.  Very small fruit (< 4 cm diameter) and those at or near maturity are almost immune.  Disease development is severe during warm, rainy weather when fruit are about a quarter size (Agrios, 2005; Menge & Ploetz, 2003; Pohronezny et al., 1994).  High relative humidity is necessary for conidial germination and plant infection.  The pathogen can overwinter as mycelium (stromata) in old infected leaves (Agrios, 2005).  

Dispersal and spread: Wind, rain, irrigation water, infected nursery plants, infected leaves, insects (Menge & Ploetz, 2003).

Hosts: Avocado is the main host; Persea spp. in the family Lauraceae, namely, P. americana (syn. P. gratissima, avocado), P. borbonia (redbay), P. drymifolia (Mexican avocado), P. palustris (swamp bay), and Persea sp. (Farr & Rossman, 2016).

Symptoms: Symptoms occur on leaves, stems, and fruit (Pohronezny et al., 1994).  On leaves, lesions initially appear as small (1-5 mm) angular, purple to purplish brown flecks or spots near leaf margins.  Over time, chlorotic halos surround older spots and are visible on both leaf surfaces.  The fungus sporulates under high humid conditions, appearing as gray, felty mycelial growths in the center of lesions. Individual lesions may coalesce forming larger regions of necrotic tissue.  Leaves become curled, deformed and may fall.

On fruit, lesions initiate as small flecks which later become slightly sunken, expand or coalesce becoming somewhat circular, and turn brown to brownish black in color.  Fissures or cracks usually develop in fruit lesions and serve as avenues for infection by other pathogens.  In certain cases, if the disease is temporarily arrested, the lesions appear as minute, raised, shiny, black specks associated with the corking of lenticels.  While blotch is usually confined to the rind of fruit, in advanced cases, the flesh may be invaded.  Once defoliation occurs, fruit may turn chlorotic, shrivel and drop.  Dark brown to black, 2-10 mm lesions may also form on green twigs and fruit pedicels (Pohronezny et al., 1994; Menge & Ploetz, 2003).

Damage Potential:  Pseudocercospora spot (blotch) is one of the most common diseases of avocado in Florida (Pohronezny et al., 1994).  Losses in avocado production may be severe and have been reported to be up to 69% in non-sprayed orchards in South Africa (Pohronezny et al., 1994; Menge & Ploetz, 2003).  Photosynthetic area can be reduced due to leaf spotting.  In severe infections, leaf wilt and drop may be expected.  In California, avocado production is a major industry producing 75% and 92% of the nation’s avocado fruit supplies (Lazicki et al., 2016).  Therefore, losses due to this pathogen is of particular concern.

Worldwide Distribution: Pseudocercospora purpurea is widespread in subtropical and tropical regions.  Asia:  India, Japan, Philippines; Africa: Cameroon, Democratic Republic of Congo, Côte d’Ivoire, Guinea, Kenya, South Africa; North America: Bermuda, Mexico, USA; Central America and Caribbean: Dominica, El Salvador, Honduras, Jamaica, Nicaragua, Panama, Puerto Rico, Trinidad and Tobago, United States Virgin Islands; South America: Argentina, Bolivia, Brazil, Chile, Guyana, Peru, Venezuela; Oceania: Australia, Palau (CABI, 2016; Farr & Rossman, 2016).

In the USA, the pathogen has been found in the states of Florida, Georgia, and Mississippi (CABI, 2016).

Official Control:  Presently, Cercospora purpurea (syn. Pseudocercospora purpurea) is on the ‘Harmful Organism Lists’ for Namibia and South Africa and P. purpurea is on the ‘Harmful Organism Lists’ for French Polynesia and New Caledonia (USDA PCIT, 2016).

California Distribution: Pseudocercospora purpurea has not been reported from California.  The pathogen is not known to be established in California.

California Interceptions:  None reported.

The risk Pseudocercospora purpurea would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Evaluate if the pest would have suitable hosts and climate to establish in California:

Score: 2

– Low (1) Not likely to establish in California; or likely to establish in very limited areas.

Medium (2) may be able to establish in a larger but limited part of California.

– High (3) likely to establish a widespread distribution in California.

Risk is Medium (2): In California, Pseudocercospora purpurea may be able to establish on avocado, under high moisture and warm climate conditions.  In the State, avocados are grown mostly along the southern coast (Lazicki et al., 2016).

2) Known Pest Host Range: Evaluate the host range of the pest.

Score: 1

Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

Risk is Low (1)The host range for Pseudocercospora purpurea is limited to Persea spp. with avocado being the main host.

3) Pest Dispersal Potential: Evaluate the natural and artificial dispersal potential of the pest.

Score: 3

– Low (1) does not have high reproductive or dispersal potential.

– Medium (2) has either high reproductive or dispersal potential.

High (3) has both high reproduction and dispersal potential.

Risk is High (3)Pseudocercospora purpurea has high reproductive potential resulting in the successive production of conidia which are mainly dependent on wind, rain, and infected plants for dispersal and spread.

4) Economic Impact: Evaluate the economic impact of the pest to California using the criteria below:

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Score: 3

– Low (1) causes 0 or 1 of these impacts.

– Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

Risk is High (3):  Infected host plants with leaf and fruit spot symptoms caused by Pseudocercospora spot (blotch) disease could lower value and yield of commercially produced avocado plants as well as affect nursery productions resulting in loss of markets.

5) Environmental Impact: Evaluate the environmental impact of the pest on California using the criteria below:

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact:

Score: 2

– Low (1) causes none of the above to occur.

Medium (2) causes one of the above to occur.

– High (3) causes two or more of the above to occur.

Risk is Medium (2):  The pathogen could significantly impact avocado plants grown for fruit and aesthetic value in private residential and public environments.

Consequences of Introduction to California for Pseudocercospora purpurea:

Add up the total score and include it here:

-Low = 5-8 point

Medium = 9-12 point

-High = 13-15 points

Total points obtained on evaluation of consequences of introduction to California = 11

6) Post Entry Distribution and Survey Information: Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

Score: 0

Not established (0) Pest never detected in California, or known only from incursions.

-Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

-Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

-High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Evaluation is not established (0):  Pseudocercospora purpurea is not established in California.

Final Score:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score:

Final Score:  Score of Consequences of Introduction – Score of Post Entry Distribution and Survey Information = 11

Uncertainty:  

None.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for Pseudocercospora purpurea is B.

References:

Agrios, G. N.  2005.  Plant Pathology (Fifth Edition).  Elsevier Academic Press, USA.  922 p.

CABI.  2016.  Pseudocercospora purpurea (spot blotch) (basic) datasheet.  Crop Protection Compendium.  http://www.cabi.org/cpc/datasheet/12266 .

Crous, P.W., A. J. L. Phillips, A. P. and Baxter.  2000.  Phytopathogenic fungi from South Africa. University of Stellenbosch, Department of Plant Pathology Press, 358 pages (referenced by Farr & Rossman, 2016).

Farr, D. F., & A. Y. Rossman.  2016.  Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA.  Retrieved August 18, 2016, from http://nt.ars-grin.gov/fungaldatabases/.

Lazicki, P., D. Geisseler, and W. R. Horwath.  2016.  Avocado production in California. https://apps1.cdfa.ca.gov/FertilizerResearch/docs/Avocado_Production_CA.pdf. (Last updated April, 2016.)

Menge, J. A., and R. C. Ploetz.  2003.  Disease of Avocado.  In Diseases of Tropical Fruit Crops, Edited by R. C. Ploetz, CABI Publishing, CAB International, UK, USA, 527 p.

Pohronezny, K. L., G. W. Simone, and J. Kotzé.  1994.  Pseudocercospora spot (blotch).  In Compendium of Tropical Fruit Diseases, Edited by R. C. Ploetz, G. A. Zentmeyer, W. T. Nishijima, K. G. Rohrbach, and H. D. Ohr, APS Press, The American Phytopathological Society, 79-80 p.

Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-262-1110, plant.health[@]cdfa.ca.gov.


Comment Period: CLOSED

45-day comment period: Nov 30, 2016 – Jan 14, 2017


Comment Format:

♦  Comments should refer to the appropriate California Pest Rating Proposal Form subsection(s) being commented on, as shown below.

Example Comment: 

Consequences of Introduction:  1. Climate/Host Interaction: [Your comment that relates to “Climate/Host Interaction” here.]

♦  Posted comments will not be able to be viewed immediately.

♦  Comments may not be posted if they:

Contain inappropriate language which is not germane to the pest rating proposal;

Contains defamatory, false, inaccurate, abusive, obscene, pornographic, sexually oriented, threatening, racially offensive, discriminatory or illegal material;

Violates agency regulations prohibiting sexual harassment or other forms of discrimination;

Violates agency regulations prohibiting workplace violence, including threats.

♦  Comments may be edited prior to posting to ensure they are entirely germane.

♦  Posted comments shall be those which have been approved in content and posted to the website to be viewed, not just submitted.


Pest Rating: B


Posted by ls

 

Insects, Mites & Earthworms

Insects and mites are related in that their skeletons are on the outside (Phyllum: Arthropoda), but differ in that adult insects have six legs and adult mites have eight.  Both groups can be beneficial, neutral or destructive to their environment.  Like nematodes, they can cause yearly losses in the billions of dollars for agricultural crops around the world.

PEST RATINGS:

ACARI

Peacock Mite | Tuckerella sp.
Pest Rating: A

 BLATTODEA

Three-lined Cockroach | Luridiblatta trivittata
Pest Rating: C

COLEOPTERA

Ambrosia Beetle | Euwallacea similis (Ferrari)
Pest Rating: A

Ambrosia Beetle |  Xylosandrus amputatus (Blandford)
Pest Rating: A

Banded Elm Bark Beetle | Scolytus schevyrewi Semenov
Pest Rating: C

A Bark Beetle | Pycnarthrum hispidum (Ferrari)
Pest Rating: C

Bark Beetle | Coccotrypes rutschuruensis Eggers
Pest Rating: A

Beetle | Anomala ausonia Erichson
Pest Rating: A

Beetle: Dactylotrypes longicollis (Wollaston)
Pest Rating: C

Beetle | Dyscinetus dubius (Olivier)
Pest Rating: A

Beetle | Semanotus sinoauster Gressitt
Pest Rating: A

Black Pine Bark Beetle | Hylastes ater (Paykull)
Pest Rating: A

Black Timber Bark Beetle | Xylosandrus germanus (Blandford)
Pest Rating: A

Black Twig Borer | Xylosandrus compactus (Eichhoff)
Pest Rating: A

Camphor Shot Borer | Cnestus mutilatus (Blandford)
Pest Rating: A

Cereal Leaf Beetle: Oulema melanopus (Linnaeus)
Pest Rating:  B

Click Beetle | Conoderus posticus (Eschscholtz)
Pest Rating: A

Coffee Bean Weevil | Araecerus fasciculatus
Pest Rating: B

Diaprepes Root Weevil | Diaprepes abbreviatus
Pest Rating: B

Dwarf Siberian Pine Beetle | Dryocoetes pini
Pest Rating: A

Garden Chafer | Phyllopertha horticola (L.)
Pest Rating: A

Granulate Ambrosia Beetle | Xylosandrus crassiusculus Motschulsky
Pest Rating: A

Hylesinus cingulatus Blandford
Pest Rating: A

Hypothenemus eruditus Westwood
Pest Rating: B

Japanese Pine Sawyer | Monochamus alternatus (Hope)
Pest Rating: A

Jewel Beetle | Actenodes auronotatus (Gory & Laporte)
Pest Rating: A

Longhorned Beetle | Acalolepta aesthetica (Olliff)
Pest Rating: A

Longhorned Beetle | Arhopalus pinetorum (Wollaston)
Pest Rating: A

Longhorned Beetle | Plagionotus arcuatus (Linnaeus)
Pest Rating: A

New Guinea Sugarcane Weevil | Rhabdoscelus obscurus (Boisduval)
Pest Rating: A

Olive Bark Beetle | Phloeotribus scarabaeoides (Bernard)
Pest Rating: B

Palmetto weevil | Rhynchophorus cruentatus (Fabricius)
Pest Rating: A

Polyphagous Shot Hole Borer: Euwallacea sp. nr. fornicatus
Pest Rating:  B

Red-Black False Blister Beetle: Ananca bicolor (Fairmaire)
Pest Rating:  B

Redneck Longhorn Beetle | Aromia bungii
Pest Rating: A

Rice Beetle | Dyscinetus morator (Fabricius)
Pest Rating: A

Sap Beetle:  Brachypeplus basalis (Erichson)
Pest Rating:  B

Scarab Beetle | Gymnetis stellata (Latreille)
Pest Rating: A

Scolytid Weevil: Pagiocerus frontalis (Fabricius)
Pest Rating:  B

Seed Beetle | Bruchidius terrenus
Pest Rating:  B

Slender-banded Pine Cone Longhorn Beetle | Chlorophorus strobilicola Champion
Pest Rating: A

Small Hive Beetle (SHB): Aethina tumida Murray
Pest Rating: B

Small Spruce Bark Beetle | Polygraphus poligraphus (L.)
Pest Rating: A

South American Palm Weevil | Rhynchophorus palmarum (Linnaeus)
Pest Rating: B

Sri Lankan weevil | Myllocerus undecimpustulatus undatus
Pest Rating:  A

Strangulate Weevil | Trochorhopalus strangulatus (Gyllenhal)
Pest Rating: A

Sugarcane Beetle | Euetheola humilis rugiceps (LeConte)
Pest Rating: A

Taiwan Slender Longhorned Beetle: Stenhomalus taiwanus Matsushita
Pest Rating: A

Trypodendron signatum (Fabricius)
Pest Rating: A

Twobanded Japanese Weevil | Pseudocneorhinus bifasciatus (Roelofs)
Pest Rating: A

Weevil | Dryophthorus homoeorhynchus Perkins
Pest Rating: C

Weevil | Oxydema longula (Boheman)
Pest Rating: C

West Indian Sugarcane Weevil | Metamasius hemipterus (L.)
Pest Rating:  C

Velvet Longhorn Beetle: Trichoferus campestris Faldermann
Pest Rating:  A

Xyleborus pfeilii (Ratzeburg)
Pest Rating: A

DIPTERA

Allium Leafminer: Phytomyza gymnostoma Loew
Pest Rating: A

Apple Leaf Gall Midge: Dasineura mali (Kieffer)
Pest Rating:  A

Daylily Leafminer: Ophiomyia kwansonis Sasakawa
Pest Rating:  B

European Pine Resin Midge | Cecidomyia pini (DeGeer)
Pest Rating: A

Ginger Maggot: Eumerus figurans (Walker)
Pest Rating:  B

An Ornamental Fig Pest: Horidiplosis ficifolii Harris
Pest Rating:  B

Striped Vinegar Fly: Zaprionus indianus Gupta
Pest Rating: B

Tomato leaf miner | Liriomyza bryoniae (Kaltenbach)
Rating: A

HEMIPTERA

Agave Mealybugs:
Paracoccus gillianae and Psuedococcus variabilis (formerly sp. A) 

Pest Rating: C

Agave Scale:  Acutaspis agavis (Townsend & Cockerell)
Pest Rating: B

Alazon Mealybug | Dysmicoccus grassii (Leonardi)
Pest Rating:  A

Annona/Gray Pineapple Mealybug | Dysmicoccus neobrevipes
 Pest Rating: A

Armored Scale | Melanaspis leivasi (Costa Lima)
Pest Rating: A

Balsam Woolly Adelgid |  Adelges piceae
Pest Rating: B

Bamboo pit scale | Bambusaspis miliaris (Boisduval)
Pest Rating: B

Banana Mealybug:  Pseudococcus elisae Borchsenius
Pest Rating:  A

Barber Giant Mealybug | Puto barberi (Cockerell)
Pest Rating: A

Bondar’s Nesting Whitefly: Paraleyrodes bondari Peracchi
Pest Rating:  A

Boxwood Scale: Pinnaspis buxi (Bouché)
Pest Rating: A

Bougainvillea Mealybug: Phenacoccus peruvianus Granara de Willink
Pest Rating: A

Bronze Bug: Thaumastocoris peregrinus Carpintero and Dellapé
Pest Rating: B

A Burrowing Bug | Rhytidoporus indentatus Uhler
Pest Rating: C

Cannabis aphid | Phorodon cannabis Passerini 
Pest Rating: A

Citrus Snow Scale:  Unaspis citri Comstock
Pest Rating:  A

Cotton Seed Bug |  Oxycarenus hyalinipennis (Costa)
Pest Rating: A

Crapemyrtle Scale: Acanthococcus lagerstroemiae
Pest Rating: A

Curtain Fig Psyllid: Macrohomotoma gladiata
Pest Rating: B

Cycad Aulacaspis Scale:  Aulacaspis yasumatsui Takagi
Pest Rating:  A

Cycad Poliaspis Scale | Poliaspis media Maskell
Pest Rating: B

Elongate Hemlock Scale: Fiorinia externa Ferris
Pest Rating: A

False Trochanter Mealybug | Pseudococcus dolichomelos Gimpel and Miller
Pest Rating: A

Ficus Leaf-rolling Psyllid: Trioza brevigenae Mathur
Pest Rating: B

Ficus Whitefly: Singhiella simplex (Singh)
Pest Rating:  B

Fig Wax Scale | Ceroplastes rusci (L.)
Pest Rating:  A

Floridana Scale: Lindingaspis floridana Ferris
Pest Rating:  B

Florida Wax Scale | Ceroplastes floridensis Comstock
Pest Rating: A

Fly Speck Scale:  Gymnaspis aechmeae Newstead
Pest Rating:  B

Garden Fleahopper: Halticus bractatus
Pest Rating: A

Gray Scale | Pseudoparlatoria ostreata Cockerell
Pest Rating: A

Gray Sugarcane Mealybug | Trionymus boninsis (Kuwana)
Pest Rating: A

Green Scale: Coccus viridis
Pest Rating: A

Harrisia Cactus Mealybug | Hypogeococcus pungens Granara de Willink
Pest Rating: A

Hemlock Scale: Hemiberlesia ithacae (Ferris)
Synonym: Abgrallaspis ithacae
Pest Rating: B

Herculeana Scale: Clavaspis herculeana
Pest Rating: A

Jack Beardsley mealybug: Pseudococcus jackbeardsleyi
Pest Rating: A

A Leafhopper | Paraulacizes irrorata (Fabricius)
Pest Rating: A

Lesser Snow Scale: Pinnaspis strachani (Cooley)
Pest Rating: A

Longan Scale: Thysanofiorinia nephelii (Maskell)
Pest Rating:  B

Magnolia White Scale: Pseudaulacaspis cockerelli (Cooley)
Pest Rating: A

Mango Scale | Aulacaspis tubercularis Newstead
Pest Rating: A

Mango Scale: Radionaspis indica
Pest Rating: B

Mango Shield Scale: Milviscutulus mangiferae (Green)
Pest Rating: A

Masked Scale: Mycetaspis personata (Comstock)
Pest Rating: A

A Mealybug: Dysmicoccus texensis (Tinsley)
Pest Rating: A

Mealybug | Ferrisia dasylirii (Cockerell)
Pest Rating: C

A Mealybug | Nipaecoccus floridensis Beardsley
Pest Rating: A

Mealybug | Palmicultor browni (Williams)
Pest Rating: A

A Mealybug | Trionymus sasae (Kanda)
Pest Rating: A

Mealybug | Vryburgia succulentarum Williams
Pest Rating: A

Mining Scale: Howardia biclavis
Pest Rating: A

Odermatt Mealybug | Pseudococcidae mealybug
Pest Rating: A

Oriental Scale: Aonidiella orientalis
Pest Rating: A

Pacific Mealybug: Planococcus minor (Maskell) 
Pest Rating: A

Palm Mealybug | Palmicultor palmarum (Ehrhorn)
Pest Rating: A

Papaya Mealybug | Paracoccus marginatus Williams and Granara de Willink
Pest Rating: A

Phorodon cannabis Passerini: cannabis aphid
Current Pest Rating: A
Proposed Pest Rating: C
Comment Period: 9/16/2019 through 10/31/2019

Pink Hibiscus Mealybug | Maconellicoccus hirsutus (Green)
Pest Rating:  A

Plant Bug | Rubrocuneocoris calvertae Henry
Pest Rating: A

A Planthopper:  Kallitaxila granulata (Stål)
Pest Rating:  A

Protea Mealybug:  Delottococcus confusus (De Lotto)
Pest Rating:  C

Protea Mealybug: Paracoccus hakeae (Williams)
Synonym: Phenacoccus hakeae
Pest Rating:  C

Red Streaked Leafhopper: Balclutha rubrostriata (Melichar)
Pest Rating: A

Red Wax Scale | Ceroplastes rubens Maskell
Pest Rating:  A

Root Mealybug: Ripersiella hibisci (Kawai & Takagi)
Pest Rating: A

Rufous Scale | Selenaspidus articulatus (Morgan)
Pest Rating: A

Seed Bugs | Nysius spp.
Pest Rating: NR

A Seed Bug | Ochrimnus mimulus (Stål)
Pest Rating: A

Soft Scale | Kilifia americana Ben-Dov
Pest Rating: A

Spanish Moss Orthezia: Graminorthezia tillandsiae (Morrison)
Pest Rating: C

Spiraling Whitefly: Aleurodicus dispersus Russell
Pest Rating: A

Spotted Lanternfly:  Lycorma delicatula White
Pest Rating:  A

Stellate Scale: Ceroplastes stellifer
Synonym: Vinsonia stellifera
Pest Rating: A

Stink Bug | Kalkadoona pallida (Van Duzee)
Pest Rating: A

Taro Planthopper: Tarophagus colocasiae
Pest Rating: B

Tea Scale of Camellia | Fiorinia phantasma Cockerell & Robinson
Pest Rating: A

Trilobe Scale: Pseudaonida trilobitiformis (Green)
Hemiptera: Diaspididae
Pest Rating: A

Tropical Palm Scale | Hemiberlesia palmae (Cockerell)
Pest Rating: A

Two-lined Spittlebug | Prosapia bicincta (Say)
Pest Rating: A

Unilobed Scale:  Pinnaspis uniloba (Kuwana)
Pest Rating:  B

Waratah Scale: Pseudaulacaspis brimblecombei Williams
Pest Rating:  A

Whitefly | Aleurotrachelus anonae Corbett
Pest Rating: A

White Fly: Asiothrixus antidesmae (Takahashi)
Pest Rating: A

White Peach Scale: Pseudaulacaspis pentagona (Targioni)
Pest Rating: A

White Prunicola Scale | Pseudaulacaspis prunicola (Maskell)
Pest Rating: A

HYMENOPTERA 

An Ant:  Ochetellus glaber (Mayr)
Pest Rating:  A

An Ant | Pheidole dentigula
Pest Rating: A

Asian Needle Ant | Brachyponera chinensis
Pest Rating: A

Bigheaded Ant: Pheidole megacephala
Pest Rating:  A

Compact Carpenter Ant | Camponotus planatus
Pest Rating: A

Difficult White-Footed Ant  |  Technomyrmex difficilis Forel
Pest Rating: A

Erythrina gall wasp: Quadrastichus erythrinae
Pest Rating: B

Eucalyptus Gall Wasp: Ophelimus maskelli (Ashmead)
Pest Rating: C

Florida Carpenter Ant | Camponotus floridanus (Buckley)
Pest Rating: A

Flower Ant | Monomorium floricola
Pest Rating: A

Little Fire Ant: Wasmannia auropunctata (Roger)
Pest Rating: A

Long-legged Ant: Anoplolepsis longipes
Pest Rating: A

Modoc Carpenter Ant: Camponotus modoc Wheeler
Pest Rating: C

Native Ant: Formica francoeuri Bolton
Pest Rating: C

Stingless Bee: Plebeia frontalis (Friese)
Pest Rating: B

Tawny Crazy Ant | Nylanderia fulva
Pest Rating: A

⇒ LEPIDOPTERA

Azalea Leafminer | Caloptilia azaleella (Brants)
Pest Rating: C

Banana Moth |  Opogona sacchari (Bojer)
Pest Rating: C

Barred Fruit-tree Tortrix | Pandemis cerasana Hübner
Pest Rating:  A

Carnation tortrix  |  Cacoecimorpha pronubana (Hübner)
Pest Rating: A

Cherry Bark Tortrix | Enarmonia formosana (Scopoli)
Pest Rating:  A

Cotton Bollworm | Helicoverpa armigera (Hübner)
Pest Rating: A

Cucumber Moth | Diaphania indica (Saunders)
Pest Rating: A

Eastern Tent Caterpillar |  Malacosoma americanum (Fabricius)
Pest Rating: A

Erythrina Twigborer: Terastia meticulosalis Guenée
Pest Rating:  B

Golden twin-spot moth: Chrysodeixis chalcites (Esper)
Pest Rating: A

Green Garden Looper | Chrysodeixis eriosoma (Doubleday)
Pest Rating:  A

Grey Tortrix | Cnephasia stephensiana Doubleday
Pest Rating: A

Leek Moth | Acrolepiopsis assectella (Zeller)
Pest Rating: A

Southern Armyworm: Spodoptera eridania (Stoll)
Pest Rating: A

Tomato Leafminer: Tuta absoluta (Meyrick)
Pest Rating: A

Winter Moth | Operophtera brumata (L.)
Pest Rating:  A

THYSANOPTERA

Bamboo Orchid Thrips: Dichromothrips smithi (Zimmerman)
Pest Rating:  A

Banana-silvering Thrips: Hercinothrips bicinctus (Bagnall)
Pest Rating: B

Biltothrips minutus (Bhatti)
Pest Rating: A

Black Vine Thrips: Retithrips syriacus (Mayet)
Pest Rating: A

Chilli Thrips:  Scirtothrips dorsalis Hood
Pest Rating: B

Cotton Bud Thrips | Frankliniella schultzei Trybom
Pest Rating: A

Japanese Flower Thrips | Thrips setosus
Pest Rating:  A

Kelly’s Citrus Thrips: Pezothrips kellyanus (Bagnall)
Pest Rating: A

Lord Howe Island Thrips | Dendrothrips howei Mound
Pest Rating: B

Melon Thrips: Thrips palmi (Karny)
Pest Rating:  A

Rose Thrips | Thrips fuscipennis
Pest Rating:  A

A Thrips | Coremothrips pallidus Hood
Pest Rating: A

Thrips | Indusiothrips seshadrii Priesner
Pest Rating: A

Thrips | Trichromothrips priesneri (Bhatti)
Pest Rating: A

Weeping Ficus Thrips: Gynaikothrips uzeli (Zimmermann)
Pest Rating:  B


EARTHWORMS | ANNELIDA

Asian Crazy Worm | Amynthas agrestis
Pest Rating:  A


MITES

Acalitus phloeocoptes (Nalepa):  plum bud gall mite
Pest Rating: A

Nematodes

(Plant Parasitic Nematodes)

Nematodes (also called ‘roundworms’) are relatively small, multicellular, worm-like animals. They are found in almost every environmental niche imaginable, living free in soil, marine and freshwater habitats while feeding on bacteria, fungi, and nematodes, or as parasites of humans, insects, fish, larger animals and plants.

Plant parasitic nematodes are abundant in many soils and may be feed on roots and other below ground plant tissue as external feeders while living outside a plant or penetrate and enter plant tissue to live and feed internally causing damage to plants. While most species of plant parasitic nematodes feed on below ground plant tissue, a relatively fewer number may inhabit and feed on above ground tissue. Billions of dollars in losses to agricultural crops due to damages caused by plant parasitic nematodes occur worldwide every year. California’s agricultural industry could lose several hundred million dollars annually in crop losses if certain plant parasitic nematodes not known to occur or of limited occurrence in California would become widespread within the State.


PEST RATINGS:

Anguina funesta
Pest Rating: A

Anguina tritici | Wheat Seed gall nematode
Pest Rating: A

Asian Citrus Root-knot Nematodes
Pest Rating:  A

Bursaphelenchus coccophilus
Pest Rating: A

Criconemoides (syn. Criconemella De Grisse and Loof 1965), Taylor 1936
Current Pest Rating: D | Proposed Pest Rating: C                        Comment Period: 9/4/2019 through 10/19/2019

Ditylenchus destructor Thourne, 1945
Pest Rating: A

Ditylenchus dipsaci (Kühn, 1857) Filipjev, 1936
Pest Rating: C

Helicotylenchus spp.
Pest Rating: C

Helicotylenchus multicinctus
Pest Rating:  B

Hemicycliophora arenaria
Pest Rating: B

Heterodera carotae Jones, 1950
Pest Rating: B

Hirschmanniella belli Sher 1968
Current Pest Rating: D | Proposed Pest Rating: C                      Comment Period: 9/4/2019 through 10/19/2019

Hirschmanniella diversa Sher 1968
Current Pest Rating: D | Proposed Pest Rating: C                      Comment Period: 9/4/2019 through 10/19/2019

Longidorus elongatus: Needle nematode
Pest Rating:  B

Meloidogyne enterolobii Yang and Eisenback, 1983.
(A Root knot Nematode)
Pest Rating: A

Meloidogyne floridensis Handoo et al., 2004
Pest Rating: A

Merlinius spp. (Allen 1955) Siddiqi, 1970
Current Pest Rating: D | Proposed Pest Rating: C                        Comment Period: 9/4/2019 through 10/19/2019

Paratrichodorus minor (Colbran, 1956) Siddiqi, 1974
Current Pest Rating: D | Proposed Pest Rating: C                            Comment Period: 9/4/2019 through 10/19/2019

Paratrichodorus porosus (Allen, 1957) Siddiqi, 1974
Current Pest Rating: D | Proposed Pest Rating: C                            Comment Period: 9/4/2019 through 10/19/2019

Paratrichodorus spp. (Siddiqi 1974) and Trichodorus spp. (Cobb 1913)
Current Pest Rating: D | Proposed Pest Rating: C                              Comment Period: 9/4/2019 through 10/19/2019

Paratylenchus spp. Micoletzky, 1922
Pest Rating: C

Pratylenchus alleni 
Pest Rating:  A

Pratylenchus coffeae
Pest Rating: B

Pratylenchus neglectus
Pest Rating: C

Pratylenchus thornei
Pest Rating: C

Quinisulcius spp. Siddiqi 1971
Current Pest Rating: D | Proposed Pest Rating: C                          Comment Period: 9/4/2019 through 10/19/2019

Radopholus similis (Cobb, 1893) Thorne, 1949
Pest Rating: A

Rotylenchulus reniformis
Pest Rating: A

Scutellonema spp. Cobb, 1913
Pest Rating: C

Tylenchorhynchus spp.
Pest Rating: C

Xiphinema index
Pest Rating: B

 


Plant Pathogens

Plant diseases can be caused by several pathogenic microorganisms including fungi, bacteria, viruses, viroids, phytoplasmas and plant parasitic nematodes. In California, several plant pathogens have evolved with native plants and consequently, caused little damage. However, many other pathogens are either not present or have only been newly discovered within the State. Without effective regulations in place, exotic pathogens may gain entry into California from other global regions through imported contaminated plant and soil commodities, and detrimentally impact the State’s agriculture and natural environments.


PEST RATING PROPOSALS:

BACTERIA:

Erwinia persicina corrig. Hao et al. 1990 
Current Pest Rating: Q
Proposed Pest Rating: B
Comment Period: 9/3/2019 through 10/18/2019

FUNGUS:

Chrysanthemum white rust | Puccinia horiana (Hennings 1901)
Current Pest Rating: Q
Proposed Pest Rating: A
Comment Period: 6/6/2019 through 7/21/2019

Colletotrichum Liriopes (Damm, P. F. Cannon & Crous, 2009)
Current Pest Rating: Q
Proposed Pest Rating: B
Comment Period: 7/11/2019 through 8/25/2019

Colletotrichum Orchidophilum (Damm, P. F. Cannon & Crous 2012)
Current Pest Rating: Q
Proposed Pest Rating: B
Comment Period: 7/11/2019 through 8/25/2019

Cronartium quercuum (Berk.) Miyabe ex Shirai 1899
Current Pest Rating: Z
Proposed Pest Rating: C
Comment Period: 8/29/2019 through 10/13/2019

Phyllosticta ampelicida (Engelmann) van der Aa 1861
Current Pest Rating: Q
Proposed Pest Rating: B
Comment Period: 8/07/2019 through 9/21/2019

Phytophthora Brassicae (De Cock & Man in ‘t Veld, 2002)
Current Pest Rating: Q
Proposed Pest Rating: B
Comment Period: 7/11/2019 through 8/25/2019

Septocyta ruborum (Lib.) Petrak. 1967
Current Pest Rating: Q
Proposed Pest Rating: C
Comment Period: 7/24/2019 through 9/7/2019

PHYTOPLASMA:

Candidatus Phytoplasma palmae (Lethal yellowing of palm phytoplasma)
Current Pest Rating: A
Proposed Pest Rating: A
Comment Period: 6/6/2019 through 7/21/2019

 

PEST RATINGS:

BACTERIA:

Acidovorax citrulli
Pest Rating:  A

Candidatus Liberibacter solanacearum
Pest Rating: B

Erwinia aphidicola
Pest Rating: B

Rhodococcus fascians
Pest Rating:  C

Xanthomonas arboricola pv. pruni
Pest Rating:  B

FUNGI:

Ascochyta aquileqiae
Pest Rating: C

Calonectria pseudonaviculata
Pest Rating:  B

Calonectria pteridis
Pest Rating: B

Cercospora coniogrammes
 Pest Rating:  B

Cercospora insulana Sacc. 1915
Pest Rating: C

Cercospora ruscicola
Pest Rating: B

Coleophoma empetri
Pest Rating: B

Colletotrichum aracearum
Pest Rating: B

Colletotrichum asianum
Pest Rating: B

Colletotrichum boninense
Pest Rating:   B

Colletotrichum cliviae
Pest Rating: B

Colletotrichum cordylinicola
Pest Rating: B

Colletotrichum cymbidiicola
Pest Rating: B

Colletotrichum fioriniae (Marcelino & Gouli) Pennycook 2017
Pest Rating: B

Colletotrichum fructicola
Pest Rating: B

Colletotrichum henanense F. Liu & L. Cai 2015
Pest Rating: B

Colletotrichum karstii
Pest Rating: B

Colletotrichum orbiculare 
Pest Rating:  B

Colletotrichum petchii
Pest Rating: B

Colletotrichum queenslandicum
Pest Rating: B

Colletotrichum sansevieriae
Pest Rating: B

Colletotrichum siamense
Pest Rating: B

Colletotrichum spaethianum
Pest Rating: B

Colletotrichum theobromicola
Pest Rating: B

Corynespora cassiicola (Berk. & M. A. Curtis) C. T. Wei 1950
Pest Rating: B

Diaporthe pseudophoenicicola
Pest Rating: C

Diaporthe pseudomangiferae
Pest Rating: C

Diaporthe vaccinii
Pest Rating: C

Didymella bryoniae
Pest Rating: B

Erysiphe aquilegiae
Pest Rating: C

Erysiphe peckii (U. Braun) U. Braun & S. Takam. 2000
Pest Rating: B

Fusarium brachygibbosum
Pest Rating: C

Ganoderma adspersum
Pest Rating: B

Geosmithia pallida
Pest Rating: C

Greeneria uvicola
Pest Rating: B

Gymnosporangium yamadae Miyabe ex G. Yamada 1904
Pest Rating: A

Ilyonectria capensis L. Lombard & Crous 2013
Pest Rating: C

Kweilingia divina
Pest Rating:  A

Marasmiellus palmivorus
Pest Rating: C

Melampsoridium hiratsukanum: Alder Rust
Pest Rating: C

Neocercosporidium smilacis (Thüm.) U. Braun, C. Nakash., Videira & Crous 2017
Pest Rating: B

Neofusicoccum mangiferae
Pest Rating: C

Peronosclerospora philippinensis
Pest Rating: C

Peronospora belbahrii
Pest Rating:  C

Peronospora digitalidis
Pest Rating: C

Peronospora mesembryanthemi
Pest Rating:  B

Phakopsora phyllanthi
Pest Rating:  C

Phyllosticta yuccae
Pest Rating: C

Phytophthora bisheria
Pest Rating:  B

Phytophthora cactorum
Pest Rating: B

Phytophthora cambivora
Pest Rating: B

Phytophthora hedraiandra
Pest Rating:  B

Phytophthora niederhauserii
Pest Rating:   B

Phytophthora parvispora
Pest Rating: B

Phytophthora quercina
Pest Rating: B

Phytophthora siskiyouensis
Pest Rating:  B

Phytophthora tentaculata
Pest Rating:  B

Plasmopara constantinescui
Pest Rating:  B

Podosphaera caricae-papayae
Pest Rating:  B

Podosphaera xanthii
Pest Rating: C

Pseudocercospora myrticola
Pest Rating:  B

Pseudocercospora purpurea
Pest Rating: B

Pseudocercospora smilacicola
Pest Rating: B

Pseudocercospora theae (Cavara) Deighton 1987
Pest Rating: C

Puccinia crepidus-japonicae
Pest Rating: D

Puccinia kuehnii 
Pest Rating: C

Puccinia psidii: Myrtle Rust
Pest Rating:  C

Ramularia slaviicola
Pest Rating: C

Sarocladium oryzae
Pest Rating:  A

Sclerophthora rayssiae var. zeae
Pest Rating: C

Septoria protearum
Pest Rating: B

Stemphylium solani 
Pest Rating: A

Thekopsora minima
Pest Rating: C

Tranzschelia mexicana
Pest Rating:  B

Uromyces transversalis
Pest Rating: C

Ustilago esculenta Henn. 1895
Pest Rating: A

PHYTOPLASMAS:

Candidatus Phytoplasma pruni
(= Peach X-disease, Peach Rosette, Peach Red Suture, and Little Peach Phytoplasmas)
Pest Rating: C

Texas Phoenix Palm Decline Phytoplasma
Pest Rating:  A

VIRUSES and VIROIDS:

Alstroemeria necrotic streak virus
Pest Rating: A 

Bamboo Mosaic Virus (BaMV)
Pest Rating: B

Cherry Virus A
Pest Rating: C

Citrus Leaf Blotch Virus
Pest Rating: B

Citrus viroid V
Pest Rating: B

Cucumber Green Mottle Mosaic Virus
Pest Rating: A

Cucurbit chlorotic yellows virus
Pest Rating: B

Cucurbit Yellow Stunting Disorder Virus
 Pest Rating:  B

Freesia Mosaic Virus
Pest Rating: B

Freesia Sneak Virus
Pest Rating:  B

Grapevine Pinot gris Virus (GPGV)
Rating: B

Grapevine Red Blotch Associated Virus
Pest Rating: B

Hibiscus Latent Fort Pierce Virus (HLFPV)
Pest Rating: B

Pea Seed-borne Mosaic Virus (PSbMV)
Pest Rating:  B

Pepino Mosaic Virus (PepMV)
Pest Rating:  B

Potato Spindle Tuber Viroid
Pest Rating:  A

Squash Vein Yellowing Virus
Pest Rating:  B

Tomato Brown Rugose Fruit Virus
Pest Rating: A

Tomato Chlorotic Dwarf Viroid
Pest Rating:  A

Tomato Mottle Mosaic Virus
Pest Rating:  B

Tomato Yellow Leaf Curl Virus
Pest Rating:  B


Snails and Slugs

Snails and slugs are among the most bothersome pests in many gardens and landscapes. They feed on a variety of living plants and on decaying plant matter. They chew irregular holes with smooth edges in leaves and flowers and can clip succulent plant parts. They also can chew fruit and young plant bark.

The brown garden snail, Cornu aspersum (formerly Helix aspersa), is the most common snail causing problems in California gardens. It was introduced from France during the 1850s for use as food. Another troublesome snail is the white garden snail, Theba pisana.

Several species of slugs also cause damage including the gray garden slug (Deroceras reticulatum, formerly Agriolimax meticulatus), the banded slug (Lehmannia poirieri), the three-band garden slug (L. valentiana), the tawny slug (Limacus flavus), and the greenhouse slug (Milax gagates).

Source (including image of tawny slug on ripe strawberry): UC IPM Online
Jack Kelly Clark, ANR Communication Services, principal photographer

PEST RATINGS:

 SNAILS

Cuban Brown Snail:  Zachrysia provisoria (Pfeiffer)
Pest Rating:  A

A Hygromiid Snail: Xerotricha conspurcata (Draparnaud) 
Pest Rating:  B

Small Pointed Snail: Cochlicella barbara (Linnaeus)
Pest Rating:  B

⇒ GASTROPODA

Banded Wood Snail:  Cepaea nemoralis
Pest Rating: A

Chinese Slug: Meghimatium bilineatum (Benson)
Pest Rating: A

A Semi-Slug: Parmarion martensi (Simroth)
Pest Rating: A


Weeds

Weeds are simply an unwanted plant in the wrong place, at the right time.  The weeds can directly and indirectly impact agricultural crops and are just as costly to the environment as any other unwanted species.


PEST RATINGS:

Alligatorweed |  Alternanthera philoxeroides  
Pest Rating: A | Proposed Seed Rating: R

American eelgrass | Vallisneria americana Michx.
Pest Rating: D | Seed Rating: Not Rated

Baby’s Breath | Gypsophila paniculata L.
Pest Rating: B |  Seed Rating: Not Rated

Balloon Plant Asclepias physocarpa
Pest Rating: C | Seed Rating: Not Rated

Barbwire Russian Thistle |  Salsola gobicola
Pest Rating : B | Proposed  Seed Rating: R

Bearded creeper | Crupina vulgaris Pers. ex. Cass.
Pest Rating: A | Proposed  Seed Rating: P

Bermuda grass | Cynodon dactylon
 Pest Rating:  D  |  Proposed  Seed Rating:  None

Bitou bush | Chrysanthemoides monilifera
Pest Rating: A  |  Proposed  Seed Rating:  R

Branched broomrape | Orobanche ramosa L.
Pest Rating: A | Proposed Seed Rating: P

Buffel grass | Pennisetum ciliare
Pest Rating: D  |  Proposed  Seed Rating:  None

Capeweed | Arctotheca calendula (L.) Levyns
Pest Rating: A |  Proposed  Seed Rating: P

Cenchrus clandestinus (Hochst. ex Chiov.) Marrone: kikuyugrass Pest Rating: C | Proposed Rating: C

Chamberbitter: Phyllanthus urinaria L.
Pest Rating: C |  Proposed  Seed Rating: R

Cheatgrass | Bromus tectorum
Pest Rating: C  |  Proposed  Seed Rating: None

Coco-Yam, Elephant Ear or Taro  |  Colocasia esculenta
Pest Rating: D |  Seed Rating: Not Rated

Common reed (Phragmites australis):

Phragmites australis cf. subsp. altissimus (non-native)
Pest Rating: C  | Proposed  Seed Rating: R

Phragmites australis subsp. americanus (native)
Pest Rating: D | Proposed  Seed Rating: None

Dagger-flower | Mantisalca salmantica (L.) Briq. & Cavill. 
Synonym: Centaurea salmantica L.
Pest Rating: A | Proposed  Seed Rating: P

Egyptian broomrape | Orobanche aegyptiaca Pers.
Pest Rating:  A  | Proposed  Seed Rating:  P

European Frogbit | Hydrocharis morsus-ranae L.
Pest Rating: A |  Proposed  Seed Rating: P

European Mistletoe |  Viscum album L
Pest Rating: A | Proposed Seed Rating: R

False Pickerel Weed | Monochoria vaginalis (Burm. f.) C. Presl ex Kunth
Pest Rating: A |  Proposed Seed Rating: R

False Yellowhead | Dittrichia viscosa (L.) Greuter
Pest Rating: A |  Proposed  Seed Rating: P

Field Bindweed | Convolvulus arvensis L.
Pest Rating: C | Proposed Seed Rating: R

Flowering-rush | Butomus umbellatus
Pest Rating:  B  |  Proposed  Seed Rating:  R

Giant Hogweed | Heracleum mantegazzianum
Pest Rating : A |  Proposed  Seed Rating: P

Giant Knotweeds:
Fallopia japonica, F. sachalinensis,
& F. X bohemica
Pest Rating: A | Proposed Seed Rating: R

Giant Ragweed | Ambrosia trifida L.
Pest Rating: B

Giant Reed |  Arundo donax
Pest Rating: B | Proposed Seed Rating: R

Goatsrue | Galega officinalis
Pest Rating:  A  | Proposed  Seed Rating:  P

Graceful Spurge | Euphorbia hypericifolia L.
Pest Rating: A | Seed Rating: Not Rated

Hedera spp. | English Ivy, Irish Ivy & Algerian Ivy
Pest Rating: None |  Proposed  Seed Rating: None

Indian swampweed | Hygrophila polysperma (Roxb.) T. Anderson
Pest Rating: A | Proposed Seed Rating: P

Japanese Hawkweed | Youngia japonica (L.) DC.
Pest Rating: B | Proposed Seed Rating: R

Jeweled distaff thistle | Carthamus oxyacantha
Pest Rating: B | Proposed Seed Rating: P

Jewels of Opar/Fameflower |  Talinum paniculatum
Pest Rating: C | Proposed Seed Rating: None

Jointed bulrush | Schoenoplectus articulatus (L.) Palla
Synonym: Scirpus articulatus L.
Pest Rating: D | Seed Rating: Not Rated

Jointvetch | Aeschynomene spp.
Pest Rating: A  |  Proposed  Seed Rating: P

Kidneyleaf Mud Plantain | Heteranthera reniformis
Pest Rating: A |  Proposed  Seed Rating: P

Laportea Canadensis
Pest Rating: D | Seed Rating: Not Rated

Lily of the Valley Vine | Salpichroa origanifolia
Pest Rating: C  |  Proposed  Seed Rating:  R

Manchurian Wild Rice | Zizania latifolia
Current Pest Rating: A | Proposed Seed Rating: R

Mexican pokeweed | Phytolacca heterotepala H. Walter
Pest Rating: A  |  Proposed Seed Rating: R

Myrtle Spurge | Euphorbia Myrsinites
Pest Rating: A | Proposed Seed Rating: R

Old man’s beard | Clematis vitalba
Pest Rating: A |  Proposed  Seed Rating: P

Orange Hawkweed | Hieracium aurantiacum
Pest Rating: B |  Proposed  Seed Rating: P

Parrotfeather Myriophyllum aquaticum (Vell.) Verdc.
Pest Rating: C | Proposed  Seed Rating: R

Paterson’s curse | Echium plantagineum L.
Pest Rating:  A  |  Proposed  Seed Rating:  P

Pickerelweed | Pontederia cordata L
Pest Rating: D | Proposed Seed Rating: None

Portuguese Broom | Cytisus striatus
Pest Rating: B |  Proposed  Seed Rating: P

Prickly Acacia | Vachellia nilotica
Pest Rating: A | Proposed Seed Rating: P

Ruby saltbush | Enchylaena tomentosa R. Br.
Pest Rating:  A |  Proposed  Seed Rating: R

Russian-thistle: Salsola tragus L.
Pest Rating:  C  | Proposed  Seed Rating:  R

Sahara Mustard | Brassica tournefortii
Pest Rating: C | Proposed Seed Rating: R

Santa Maria feverfew | Parthenium hysterophorus L.
Pest Rating: A  |  Proposed  Seed Rating: P

Senegal tea plant | Gymnocoronis spilanthoides
Synonym: Alomia splanthoides
Pest Rating: A  |  Proposed  Seed Rating: P

Shining cranesbill | Geranium lucidum L
Pest Rating:  A | Proposed  Seed Rating: R

Slender snakecotton | Froelichia gracilis (Hook.) Moq.
Pest Rating:  D | Proposed  Seed Rating: None

Slender Russian Thistle | Salsola collina Pallas
Pest Rating: A | Proposed Seed Rating: P

Smallflower Hawksbeard | Crepis pulchra
Pest Rating: C | Proposed Seed Rating: R

Snail Medic | Medicago scutellata (L.) Wilson
Pest Rating:  D | Seed Rating: Not Rated

South American spongeplant | Limnobium laevigatum
Pest Rating: A | Proposed  Seed Rating: P

Spanish Heath | Erica lusitanica
Pest Rating: B |  Proposed  Seed Rating: R

Spanish Mercury | Mercurialis ambigua
Pest Rating: B  | Proposed  Seed Rating: R

Tree of Heaven | Ailanthus altissima (Miller)
Pest Rating: C | Proposed Seed Rating: R

Tree Spurge | Euphorbia dendroides
Pest Rating:  B  | Proposed  Seed Rating:  R 

Tropical Whiteweed | Ageratum conyzoides L.
Pest Rating: C | Proposed Seed Rating: None

Turkey Berry | Solanum torvum
Pest Rating: C | Seed Rating: Not Rated

Volutaria tubuliflora (Murb.) Sennen
Rating: A | Proposed Seed Rating: R

Wall Fumitory | Fumaria muralis Sand W.D. J. Koch
Pest Rating: C | Seed Rating: Not Rated

Ward’s weed  |  Carrichtera annua
Rating: A  |  Proposed  Seed Rating: R

Water hyacinth | Eichhornia crassipes
Pest Rating: None | Proposed  Seed Rating: None

West Indian Woodnettle |  Laportea aestuans
Pest Rating: C |  Seed Rating: Not Rated

Winged Water-Primrose | Ludwigia decurrens
Pest Rating: A  | Proposed  Seed Rating: P

Yellow-Flag Iris | Iris pseudacorus L.
Pest Rating: B | Proposed  Seed Rating: R

Yellow Floating-heart | Nymphoides peltata (Gmel.) Kuntze
Pest Rating: A  | Proposed  Seed Rating: R