Category Archives: Ratings

Cepaea nemoralis – Banded Wood Snail

California Pest Rating
Cepaea nemoralis – Banded wood snail
Gastropoda: Helicidae  
Former Pest Rating: Q
CURRENT Pest Rating: A

 


Comment Period: 11/7/17 – 12/22/17 (CLOSED)


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

Giant Reed | Arundo donax

California Pest Rating
Arundo donax  (Giant Reed)
Family: Poaceae
Former Pest Rating: B
CURRENT Pest Rating: B  | Proposed Seed Rating: R
Initiating Event:

There have been queries about growing tracts of giant reed in CA for use in biofuel production.

History & Status:

Background: Arundo donax is a tall, erect, perennial cane or bamboo-like grass, 2 to 8 meters high. It is one of the largest of the herbaceous grasses. The fleshy, almost bulbous, creeping root stocks form compact masses from which arise tough, fibrous roots that penetrate deeply into the soil. The culms reach a diameter of 1 to 4 cm and commonly branch during the second year of growth. These culms are hollow, with walls 2 to 7 mm thick and divided by partitions at the nodes. The nodes vary in length from 12 to 30 cm. The leaves are conspicuously two-ranked, 5 to 8 cm broad at the base and tapering to a fine point. The bases of the leaves are cordate and more or less hairy-tufted, persisting long after the blades have fallen. There can be variability in leaf and cane dimensions within a stand, possibly in response to water availability. Arundo donax was widely planted in the 19th century in CA for its bamboo-like stems. It’s planting was actively promoted in the 1950s by the USDA for use in erosion control along stream banks.

Arundo donax has been nominated as one of the top 100 Worst Invaders of the World by the Invasive Species Specialist Group of the World Conservation Union (http://www.issg.org). It was first introduced to the United States by Spanish colonists in the 1700’s and introduced again to California in the early 1800’s for erosion control in drainage canals. It is now a major invasive threat to riparian areas in California, as well as other southwestern states and it is listed as one of the twenty most invasive weeds in California and as a noxious weed in Texas.

Large infestations of Arundo donax are difficult to eradicate given that all

rhizomes must be removed or killed to prevent re-sprouting. This can cost from $7000-$25000 per acre, depending on difficulty of access. Typically a combination of mechanical removal and application of a systemic herbicide (e.g., glyphosate) provide the best control. Care must be taken to ensure that removed plant material does not sprout. Research on the biological control of Arundo donax in the United States has led to the recent release of a wasp, Tetramesa romana Walker (Hymenoptera: Eurytomidae), but its effects on population levels of Arundo donax are currently unknown .

 Worldwide Distribution: Arundo donax is native to many tropical to warm temperate regions from northern Africa and the Middle East eastwards through eastern and southeastern Asia (CABI, 2011a). It has been introduced into similar climates around the world in southern Europe, Central America, South America, and the Caribbean. It is invasive in southern Africa, the western United States, southern Europe, and the Azores (Weber, 2003).

California Distribution: Arundo donax is found along waterways throughout much of CA as far north as southern Humboldt County. It is missing from Northeastern CA, the high mountains, and it is rare in the desert region (Consortium of California Herbaria).

California Interceptions: Arundo donax is occasionbally sold in nurseries in CA and has been detected during nursery surveys.

This risk Arundo donax would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: The risk of Arundo donax is High (3) as illustrated by the broad distribution of the pest in California and its spread over the last 100 years.

-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) Host range.  Arundo donax does not require any one host, but grows wherever ecological conditions are favorable. It receives a High (3) in this category.

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

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: Arundo donax is a plant that spreads via water flow and human dispersal from rhizomes or stem fragments. It does not reproduce from seed in North America. The Risk is Medium (2).

Evaluate the 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 Medium (2) as Arundo donax only occasionally invades agricultural land. It can lower yields in some ranching systems, where Arundo donax blocks access to water. Although Arundo donax was once recommended for stream bank stabilization, its shallow roots mean that bank undercutting is frequent in Arundo donax infestations. Bridge and levee damage or failure have been partially ascribed to dense Arundo donax stands, due to flow conveyance loss.

Evaluate the economic impact of the pest to California using these criteria: Economic Impact: B, 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: 2

-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) in California, as Arundo donax is an ecological transformer, it excludes native riparian species, leads to unshaded streams detrimental to migratory fish stocks, increases fire frequency, and degrades endangered species habitat (e.g., willow fly catcher).

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

Environmental Impact Score: 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 Arundo donaxRating (Score) High (13)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Arundo donax is widespread in CA. It receives a High (-3) 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.

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (10)

Uncertainty:

As this plant is well established as an invasive species in CA, there is little uncertainty associated with this assessement.

Conclusion and Rating Justification:

Based on the score listed above the pest is a high risk. This would justify an “A” rating if the species were not widely established in California. As the plant is found in over 50% of California counties, the pest would best be assigned a “B” or “C” rating. Many millions of dollars have been spent (by the state and other entities) to control Arundo donax in California. Many millions more will be spent in the near future. A “B” rating recognizes the large range of Arundo donax in California, but acknowledges the value of excluding it from new areas and preventing reinfestation of eradicated infestations.


References:      

Bell, G. P. 1997. Ecology and management of Arundo donax, and approaches to riparian habitat restoration in Southern California. In Plant Invasion: Studies from North America and Europe. J.H. Brock, M. Wade, P. Pysek and D. Green, eds. Leiden, the Netherlands: Backhuys, pp. 104-114.

Boose, A.B. and J.S. Holt. 1999. Environmental effects on asexual reproduction in Arundo donax. Weed Research 39:117-127.

Consortium of California Herbaria. Accessed 6/12/2014: ucjeps.berkeley.edu/consortium/

Goolsby, J. A., D. Spencer, and L. Whitehand. 2009. Pre-release assessment of impact on Arundo donax by the candidate biological control agents Tetramesa romana (Hymenoptera: Eurytomidae) and Rhizaspidiotus donacis (Hemiptera: Diaspididae) under quarantine conditions. Southwestern Entomologist 34:359-376.

Newhouser, M., C. Cornwall and R. Dale. 1999. Arundo: A Landowner Handbook. Accessed 6/12/2014: http://teamarundo.org/education/landowner_handbook.pdf

Perdue, R.E. 1958. Arundo donax: source of musical reeds and industrial cellulose. Economic Botany 12:368-404.

Racelis, A.E., Goolsby, J., Moran, P.J. 2009. Seasonality and movement of adventive populations of the arundo wasp (Hymenoptera: Eurytomidae), a biological control agent of giant reed in the Lower Rio Grande Basin in south Texas. Southwestern Entomologist. 34(4):347-357.

USDA Arundo donax. Accessed 6/12/2014: http://plants.usda.gov/core/profile?symbol=ardo4

Weber, E. 2003. Invasive Plant Species of the World: A Reference Guide to Environmental Weeds. CABI Publishing, U.K. 4. Dudley, T., Department of Integrative Biology, University of California, Berkeley, USA and IUCN/SSC Invasive Species Specialist Group (ISSG). 2006. Arundo donax. Accessed 6/12/2014: http://www.issg.org/database/species/ecology.asp?si=112&fr=1&sts=sss&lang=EN

Wijte, A.H. B. M., T. Mizutani, E.R. Motamed, M.L. Merryfield, D.E. Miller and D.E. Alexander. 2005. Temperature and endogenous factors cause seasonal patterns in rooting by stem fragments of the invasive giant reed, Arundo donax (Poaceae). Int. J. Plant Sci. 166(3):507-517.


Responsible Party:

Dean G. Kelch, Primary Botanist; California Department of Food and Agriculture; 1220 N Street, Sacramento, CA 95814; Tel. (916) 403-6650;

dean.kelch[@]cdfa.ca.gov


Comment Period: 11/6/17 – 12/21/17 (CLOSED)


Pest Rating: B  | Proposed Seed Rating: R

Odermatt Mealybug | Pseudococcus odermatti

California Pest Rating
Pseudococcus odermatti – Odermatt mealybug
Hemiptera: Pseudococcidae
Former Pest Rating: Q
CURRENT Pest Rating: A
Initiating Event:

Pseudococcus odermatti is frequently intercepted by CDFA. Currently it has a temporary rating of Q. A pest rating proposal is required to assign a permanent pest rating.

History & Status:

Background: Pseudococcus odermatti is commonly known as odermatt mealybug. Like other species in the genus Pseudococcus, odermatt mealybug can feed on a variety of cultivated plants. Known hosts include: Annonaceae: Sugar apple (Annona squamosa); Araliaceae: Fetsia paper plant (Fatsia japonica), Araceae: Aglaonema spp., Rosaceae: Pyracantha spp., Ebenaceae: Diospros spp., Pittosporaceae: Japanese cheesewood (Pittosporum tobira), Rutaceae: (Citrus aurantium & Citrus latifolia) 1, 4.

Worldwide Distribution: Pseudococcus odermatti is established in Bahamas, Belize, China, Costa Rica, India and Japan. In the United States it is reported from Hawaii and Florida1.

Official Control:  There is no data available for Pseudococcus odermatti, but Pseudococcus spp. are listed as harmful organisms in Dominica, Grenada, Japan, Saint Luci, Taiwan and Panama 3.

California Distribution: Pseudococcus odermatti has never been found in the environment of California.

California Interceptions: Pseudococcus odermatti is regularly found by CDFA’s high risk inspections, border stations, dog teams, and nursery inspections. Between January 1, 2000 and November, 2016 this mealybug was intercepted 94 times, typically on nursery stock and fresh plant parts from Florida and Hawaii2.

The risk Pseudococcus odermatti would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Pseudococcus odermatti feeds on a large variety of plants cultivated in California, especial widely planted citrus. It is likely to establish wherever host plants are grown and receives a High (3) in this category.

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: Pseudococcus odermatti feeds on seven different families of plants which grown throughout in California1. It has a moderate host range. It receives a Medium (2) in this category.

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.

3) Pest Dispersal Potential: Most species of Pseudococcus genus are famous for their high reproductive rates. They may spread long distances when host plants are moved. Furthermore, they may be spread by wind or by hitchhiking on clothing, animals, or equipment.

Pseudococcus odermatti receives a High (3) in this category.

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: Pseudococcus odermatti is considered an economic pest of several crops that are grown in California and may be expected to lower crop yields and increase crop production costs. If the scale were to enter the state, it may disrupt markets for fresh fruit and nursery stock. It has the potential to trigger loss of markets. Pseudococcus odermatti receives a High (3) in this category.

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: Pseudococcus odermatti is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes. It is not expected to directly impact threatened or endangered species. It can increase production costs to growers if they perform any treatment to control its infestation. It is not expected to have significant impacts on cultural practices, home/urban gardening, or ornamental plantings. It receives a Medium (2) in this category.

Evaluate the Environmental impact of the pest to California using the criteria below:  

Environmental Impact:  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 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 Odermatt mealybug:  High (13)

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Pseudococcus odermatti has never been found 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: 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:

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

Uncertainty:

Pseudococcus odermatti is commonly intercepted. There have been no formal surveys for this scale in the state. It is therefore possible that it could be present in some locations in California.

Conclusion and Rating Justification:

Pseudococcus odermatti has never been found in the environment of California and its entry to the state has potentially significant economic and environmental impacts. An “A” rating is justified.

References:
  1. Miller & Williams 1997, Downie, D.A. Gullan, P.J. Scale Net. Accessed 12-19-16 http://scalenet.info/catalogue/Pseudococcus%20odermatti/
  2. 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
  3. USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD).             https://pcit.aphis.usda.gov/pcit/
  4. USDA,  APHIS, Identification Technology Program,  Fact sheet   Accessed on 12-19-16 http://idtools.org/id/scales/factsheet.php?name=7011

Responsible Party:

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


Comment Period: CLOSED

9/12/17 – 10/27/17*


*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.


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Myocastor coypus | Nutria

California Pest Rating
Myocastor coypus (Nutria)
Former Pest Rating: Not Rated
CURRENT Pest Rating: A
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.

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:

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Pest Rating: A

Thekopsora minima P. Syd. & Syd. 1915

California Pest Rating for
Thekopsora minima P. Syd. & Syd. 1915
Former Pest Rating:  Q
CURRENT Pest Rating: C
Initiating Event:

On May 2, 2017, a shipment of blueberry (Vaccinium corymbosum) plants showing symptoms of rust were intercepted in San Francisco by San Francisco County Agricultural Officers.  The shipment had originated in Oregon and was destined to a wholesale garden store in San Francisco.  A sample of symptomatic leaves was collected by the County and sent to the CDFA Plant Pathology Lab for diagnosis.  On May 22, 2017, Suzanne Latham, CDFA plant pathologist, identified the fungal pathogen associated with the diseased leaf tissue as Thekopsora minima.  The pathogen was assigned a temporary Q rating.  Subsequently, the consequences of introduction and establishment of T. minima in California are assessed and a permanent rating is proposed herein.

History & Status:

Background: Thekopsora minima is a fungal pathogen that causes rust disease in blueberries, cranberries, rhododendrons, and other plants in the Ericaceae family.  The pathogen completes its life cycle on two different hosts (heteroecious), namely, blueberries and hemlock, and rust disease can lead to extensive defoliation of severely infected plants.

The blueberry leaf rust pathogen was first recorded as endemic in Northeastern America and Japan.  During the past decade, it was introduced on infested Vaccinium corymbosum to other countries including South Africa, Mexico, Australia and Colombia (EPPO, 2016). In the USA, it has been reported mainly from northeastern states and, more recently, from the Western Pacific states of Oregon and California (Wiseman et al., 2016; Shands et al., 2017).

Prior to 1993, taxonomically, Thekopsora minima was generally accepted as a member of a species complex known as Pucciniastrum vaccinii, which was considered the causal agent of blueberry rust.  However, Sato et al., (1993) identified three distinct rust fungi species on Vaccinium spp., of which one of them, namely, T. minina, is pathogenic on blueberry, while the other two species, Naohidemyces vaccinii (formerly P. vaccinii) and N. fujisanensis, were not regarded as pathogens of blueberry, although they infected other Vaccinium species.  Sato et al., (1993) also noted that at that time, T. minima, occurred, in eastern North America and Japan.  Nevertheless, because of the past taxonomic confusion of the species complex, the true global distribution of T. minima may be uncertain as some records attributed to Pucciniastrum vaccinii in Argentina, Hawaii (USA), and Spain may be misidentifications of T. minima (Schrader & Maier, 2015).  Thekopsora minima is also known by its synonyms: Peridermium peckii Thüm, 1880, Uredo minima Schwein, 1922, and Pucciniastrum minimum (Schwein.) Arthur 1906 (Farr & Rossman, 2017).

In California, Naohidemyces vaccinii has been reported on Vaccinium membranaceum (thin leaf huckleberry), V. caespitosum (dwarf bilberry), V. parvifolium (red huckleberry), V. ovatum (California huckleberry), and Vaccinium sp. (French, 1989).  However, recent reports from several states in the US (Oregon and Michigan), China, Mexico, and South Africa, have indicated that Thekopsora minima is the primary pathogen on northern and southern highbush blueberries (Rebollar-Alviter et al., 2011; Shilder & Miles, 2011; Wideman et al., 2016; Zheng et al., 2017).  Rust symptoms have been occasionally observed on various southern highbush blueberry cultivars (Vaccinium corymbosum) within California’s central coastal area, with particular incidences noted in Santa Barbara County in 2010 and 2006 (personal communications: Dr. Timothy D. Miles, Assistant Professor of Plant Pathology, California State University Monterey Bay, and Dr. Janet C. Broome, Global Plant Healthy Senior Manager, Driscoll’s, 2017).  Rust in blueberry was also observed in Ventura County, and has most likely been in the State since the early 2000s (personal communication: Dr. Janet C. Broome, Driscoll’s, 2017). In 2016-2017, rust symptoms, observed on several blueberry plants and cultivars in a field trials in Watsonville, Santa Cruz County, were confirmed by molecular sequencing to be caused by T. minima and marked a first published report of this pathogen in California (Shands, et al., 2017).  On August 9, 2017, in order to officially substantiate the presence of blueberry rust in California, official samples of symptomatic blueberry plant tissue were collected from infected plants in Santa Cruz and Ventura Counties, by the respective County Agricultural officials and submitted to the CDFA Plant Pathology Laboratory for identification of the associated pathogen.  Following morphological and molecular sequence analysis, Cheryl Blomquist, CDFA plant pathologist, confirmed the pathogen to be T. minima.

Disease developmentTeliospores of T. minima hibernate on blueberry leaves on the ground and after germination in late spring, infest the alternate host, Tsuga spp., via basidiospores.  Aeciospores are produced and infest Vaccinium and other Ericaceae host plants resulting in the production of urediniospores.  The latter ensure disease spread within the crop during the entire growing season.  Furthermore, it has been shown that other closely related blueberry rust species are capable of surviving as mycelium in plant buds and directly producing urediniospores in spring, thereby eliminating the need of the alternate host (EPPO, 2016).  It is not known if this is the case for T. minima in California where two native host species, Tsuga heterophylla and T. mertensiana can serve as alternate hosts for the pathogen to complete its lifecycle.  These two species are also native to the Pacific western states although the fungus has not been recovered from Tsuga (Wiseman et al., 2016; Shands, et al., 2017).  The other two hemlocks that are alternate hosts, T. canadensis and T. diversifolia, are not generally cultivated in California but may be present in small areas of private production and nurseries.  Pfister et al., 2004, experimentally determined the predicted optimum temperature for urediniospores to be 19.5°C, with a 5% variation in uredinia production between 17.5 and 22°C.

Dispersal and spread: Spores of Thekospora minima are spread over short distances to nearby plants by wind and rain. Spores may also be spread by human contact, clothing, equipment and packaging.  Long distance spread occurs mainly through passage of infected plants including fruit to non-infected regions (EPPO, 2016, Tasmania, 2014).

Hosts: The uredinial and telial stages of the pathogen are found on the main hosts in Vaccinium spp., namely, V. angustifolium var. laevifolium (lowbush blueberry), V. corymbosum (highbush blueberry), V. membranaceum (deciduous huckleberry) and V. erythrocarpum (southern mountain cranberry) in the family Ericaceae.  Other hosts belong to different genera in the same family: Azalea sp., A. pontica var. daviesii, Gaylussacia sp., G. baccata (black huckleberry), Leucothoe sp., Lyonia nezikii, L. ovalifolia var. elliptica, Menziesia sp., Pernettya sp., Pieris sp., Rhododendron nudiflorum, R. ponticum, and Rhodora canadensis.  The aecial stage of the pathogen is found on the alternate host, Tsuga spp., (hemlock; Pinaceae), T. canadensis (eastern hemlock), T. diversifolia (Japanese hemlock), T. heterophylla (western hemlock), T. mertensiana (mountain hemlock) (EPPO, 2016; Farr & Rossman, 2017; Wiseman et al., 2016).

Symptoms: Initial symptoms appear as small yellow, chlorotic leaf spots on upper surfaces of young leaves. As infection progresses these lesions turn rust or brown-colored, enlarge and coalesce covering large areas of a leaf.  On the underside of leaves, small flecks surrounded by water-soaked halos develop turning into yellow-orange, powdery pustules containing uredinia with urediniospores.  Pustules may also develop on blueberry fruit.  In severe infections premature leaf drop and plant defoliation can occur and result in decline in fruit yield and flower production (EPPO, 2016).

Damage Potential: Blueberry rust disease caused by Thekopsora minima may result in plant defoliation and decline in fruit and flower production.  Generally, under conditions of high humidity required for rust fungi infection, significant losses in blueberry production and other Ericaceae host plants can be expected. However, in California, such high humidity climates are not anticipated in blueberry cultivated regions and T. minima has not caused significant rust disease in blueberry, even though it has been in the State for over 17 years ((personal communication: Dr. Janet C. Broome, Driscoll’s, 2017).  Infected plants do not suffer from leaf drop, which is generally associated with the rust, and the pathogen has not been an issue of concern for blueberry growers to warrant administration of control measures.  Some rust disease is apparent on leaves from early spring into summer following periods of significant rain, however, it is difficult to find infected plants later in the season (personal communications: Dr. Janet C. Broome, Driscoll’s, 2017 and Dr. Timothy D. Miles, CSUMB).  Similarly, economic damage to other environmental host plants is expected to be minimal as the pathogen has already been in California for several years without any significant increase of its impact.

Worldwide DistributionAsia: China, Japan; Africa:  South Africa; Europe: Netherlands (restricted distribution), Portugal (present, few occurrences); North America: Canada, Mexico, USA; South America: Colombia; Oceania: Australia (New South Wales, Queensland, Victoria) (EPPO, 2016, 2017; Mostert et al., 2010; Zheng et al., 2017).

In Europe, the pathogen is currently regarded as “Transient, under eradication” in Belgium and Germany (EPPO, 2017).  In the USA, it has been reported from Delaware, Massachusetts, Michigan, New York and Oregon (EPPO, 2017; Sato et al., 1993; Schilder & Miles, 2011; Wiseman et al., 2016).

Official ControlThekopsora minima has been on the EPPO Alert List for the European Union since 2016 (EPPO, 2017).  Presently, Thekoposora minima is on the ‘Harmful Organism List” for Peru (USDA PCIT, 2017).

California Distribution: Thekopsora minima has officially been detected in Santa Cruz and Ventura Counties.  The pathogen has also been reported from Santa Barbara County (Shands et al., 2017).

California Interceptions: Thekopsora minima has only been detected once in a shipment of blueberry plants intercepted in San Francisco in 2017 (see “Initiating Event”).

The risk Thekopsora minima would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Main hosts of Thekopsora minima are in the family Ericaceae and include blueberries, rhododendrons and azaleas.  Blueberries are grown in northern coastal and southern coastal regions and in the San Joaquin Valley.  Rhododendrons, azaleas and other horticultural hosts are grown throughout California particularly in coastal climates.  However, because T. minima requires high humidity for infection and development in order to cause significant disease, it would only be likely to establish in very limited areas of the State.  The pathogen is already established in several coastal areas, for the past several years, and rust disease appears typically only during early spring to summer following significantly wet periods.

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

Score: 1

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: Thekopsora minima has a moderate host range.  Main hosts of the pathogen are in the family Ericaceae and include blueberries, rhododendrons, and azaleas.

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.

3) Pest Dispersal Potential: Urediniospores are produced in abundance and ensure disease spread within the crop during the entire growing season. Spores are spread over short distances to nearby plants by wind and rain and may also be spread by human contact, clothing, equipment and packaging.  Long distance spread occurs mainly through passage of infected plants including fruit to non-infected regions.

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: While blueberry rust disease has been reported to cause plant defoliation, this has not been the case in California, even though the fungus has been present in the State for several years. Blueberry growers have noted that some rust disease is apparent on blueberry leaves from early spring into summer following periods of significant rain, however, it is difficult to find infected plants later in the season.  Infected plants do not suffer from leaf drop, which is generally associated with the rust, and the pathogen has not been an issue of concern for blueberry growers to warrant administration of control measures.  No yield loss due to this rust pathogen in California has been observed or reported (see; ‘Damage Potential’).

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

Economic Impact: None

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: 1

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: Although, horticultural and environmental plants, such as azaleas and rhododendrons, are hosts of Thekopsora minima (see: ‘Hosts’), the pathogen has not increased in its spread or impact in cultivated communities over the past several years of its presence in California.  Therefore, no significant impact on the environment or home/ornamental plantings is expected.

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

Environmental Impact:  None

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: 1

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 Thekopsora minima: Low (8)

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 LowThekopsora minima has officially been detected only in few coastal counties in California.

Score: (-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.

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 = 7

Uncertainty:  

It is not known if the pathogen will infect hemlock (Tsuga spp.) in California, to complete its life cycle.  The pathogen was not recovered from hemlock in California and Oregon (Pacific coastal regions).  Hemlock species are widespread in California.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for Thekopsora minima is C.

References:

Calflora.  2017.  Information on California plants for education, research and conservation. [web application]. 2017. Berkeley, California. The Calflora Database [a non-profit organization].  http://www.calflora.org/

EPPO.  2017.  Thekopsora minima (THEKMI).  EPPO Global Database (last updated: 2017-05-19).  https://gd.eppo.int/taxon/THEKMI/distribution.

French, A.M. 1989. California Plant Disease Host Index. California Department of Food and Agriculture, Sacramento (Updated online version by T. Tidwell, May 2, 2017).

Mostert L., W. Bester, T. Jensen, S. Coertze, A. van Hoorn, J. Le Roux, E. Retief, A. Wood, and M C. Aime.  2010.  First report of leaf rust of blueberry caused by Thekopsora minima on Vaccinium corymbosum in the Western Cape, South Africa.  Plant Disease 95: 478.

Pfister, S. E., S. Halik, and D. R. Bergdahl.  2004.  Effect of temperature on Thekopsora minima urediniospores and uredinia.  Plant disease, 88: 359-362.

Rebollar-Alviter, A., A. M. Minnis, L. J. Dixon, L. A. Castlebury, M. R. Ramirez-Mendoza, H. V. Silva-Rojas, and G. Valdovinos-Ponce.  2011.  First report of leaf rust of blueberry caused by Thekopsora minima in Mexico. Plant Disease 95: 772.

Sato, S., K. Katsuya, and Y. Hiratsuka.  1993.  Morphology, taxonomy and nomenclature of Tsuga-Ericaceae rusts.  Transactions of the Mycological Society of Japan 34: 47-62.

Schilder, A. M. C., and T. D. Miles.  2011.  First report of blueberry leaf rust caused by Thekopsora minima on Vaccinium corymbosum in Michigan.  Plant Disease, 95: 768.  https://doi.org/10.1094/PDIS-12-10-0884.

Schrader, G., and W. Maier.  2015.  Express – PRA for Thekopsora minima occurrence. Julius Kühn-Institute, Institute for Plant Health.  Translated by Elke Vogt-Amdt.  http://pflanzengesundheit.jki.bund.de/dokumente/upload/fee0d_thekopsora-minima_express-pra.pdf

Shands, A. C., T. Ho, and T. D. Miles.  2017.  First report of leaf rust on southern highbush blueberry caused by Thekopsora minima in California.  Plant Disease (Accepted for publication).

Tasmania.  2014.  Blueberry rust (Thekopsora minima P. Syd & Syd).  Biosecurity Tasmania Fact Sheet, current as at October 2014. http://www.dpipwe.tas.gov.au/biosecurity/plant-biosecurity/pests-and-diseases.

USDA PCIT.  2017.  USDA Phytosanitary Certificate Issuance & Tracking System. Retrieved May 31, 2017. 6:30:49 pm CDT.  https://pcit.aphis.usda.gov/PExD/faces/ReportHarmOrgs.jsp.

Wiseman, M. S., M. I. Gordon, M. L. Putnam.  2016.  First report of leaf rust caused by Thekopsora minima on Northern highbush blueberry in Oregon. Plant Disease 100: 1949.

Zheng, X., G. Tang, Y. Tian, X. Huang, X. Chang, H. Chen, H. Yang, S. Zhang, and G. Gong.  2017.  First report of leaf rust of blueberry caused by Thekopsora minima in China. Plant Disease 101: 835.  https://doi.org/10.1094/PDIS-09-16-1379-PDN


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

June 29, 2017 – August 22, 2017 (Extended)


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: C

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 AND PROPOSALS:

Nutria |  Myocastor coypus
Pest Rating:  A

Stemphylium solani G. F. Weber 1930

California Pest Rating
Stemphylium solani G. F. Weber 1930
Former Pest Rating:  Not Rated
CURRENT Pest Rating: A
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:

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

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Pest Rating: A

 

Pseudocercospora purpurea (Cooke) Deighton 1976

California Pest Rating
Pseudocercospora purpurea (Cooke) Deighton 1976
Former Pest Rating:  Not rated
Current Pest Rating: B
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

 

 

Aleurodicus dispersus Russell (Spiraling Whitefly)

California Pest Rating
Aleurodicus dispersus Russell (Spiraling Whitefly)
Hemiptera:  Aleyrodidae
Former Pest Rating:  Q
FINAL Pest Rating: A
Initiating Event:  

In October 2013, USDA released a DEEP report proposing to deregulate Aleurodicus dispersus (spiraling whitefly).  The insect is currently “Q”-rated by CDFA, so a pest rating proposal is needed to determine future direction.

History & Status:

Background:  Spiraling whitefly is highly polyphagous, feeding on plants in 49 different plant families.  Known hosts include such economically important pests as avocado, citrus, eggplant, pepper, rose, Prunus spp., and palms.  Interceptions indicate that the whitefly often moves long distances in the trade of plants and flowers.

Worldwide Distribution: The native range of spiraling whitefly is believed to be the tropical Americas.  It was described from Florida in 1965 from specimens collected as early as 1950.  Since then it has been found to have a widespread distribution including Hawaii, Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, and Mexico.  Furthermore, it is reported in numerous nations in Central America, the Caribbean, South America, Europe and the Middle East, Africa, Asia, and Oceania.

Official Control: Arizona has a state quarantine against all citrus whiteflies.  Aleurodicus dispersus is also listed as a harmful organism by Antigua and Barbuda, Chile, China, French Polynesia, Grenada, Guatemala, Honduras, Israel, Japan, Jordan, Korea, Mexico, Morocco, and New Zealand2.

California Distribution:  Spiraling whitefly has not been found in the environment of California.

California Interceptions:  Spiraling whitefly is frequently intercepted on shipments of plants, leaves, and flowers from Hawaii and Florida.  It has been intercepted more than 1300 times since 11/29/2000.

The risk spiraling whitefly would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Spiraling whitefly has been present in Florida for over 60 years but has not spread beyond the central portion of the state. Primarily a tropical species, it is reportedly limited by cold temperatures.  In California the whitefly would likely be limited to southern and coastal areas.  Spiraling whitefly receives a Medium (2) in this category.

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

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: Spiraling whitefly is a highly polyphagous insect that is known to feed on plants from 49 different plant families.  The whitefly receives a High(3) in this category.

Evaluate the host range of the pest. Score:

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: Whiteflies reproduce rapidly and can be spread long distances by wind or through the movement of plants and flowers.  Spiraling whitefly receives a High(3) in this category.

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: Spiraling whitefly was originally considered an economic pest in Hawaii when it was introduced.  However, damage is now limited as a successful biological control agent was introduced.  In the absence of this biological control agent in California, the whitefly may be expected to lower crop yield by both sucking juices from plants and reducing their photosynthetic capacity by contaminating leaf surfaces with sooty mold.  They may also lower crop value by triggering treatment and/or disfiguring nursery stock with their presence and with sooty mold.  Furthermore, Arizona maintains a quarantine against all citrus whiteflies and many of California’s trading partners list Aleurodicus dispersus as a harmful organism.  This could lead to disruptions in markets for California citrus.  Spiraling whitefly receives a High(3) in this category.

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

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: Rosa minutafolia (small-leaved rose) is listed as an endangered species in California and is a potential host for spiraling whitefly.  The whitefly may also trigger additional chemical treatments.  The whitefly receives a High(3) in this category.

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:

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 Aleurodicus dispersus (Spiraling Whitefly):  High(14)

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: Spiraling whitefly has not been found in the environment of California. It receives a Not established(0) in this category.

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: High(14)

Uncertainty:

Spiraling whitefly has been intercepted more than a thousand times in California.  However, it has never been found in the environment.  This may indicate that environmental conditions in the state are unfavorable for establishment of the species.

Conclusion and Rating Justification:

In the absence of a successful biological control program in California, spiraling whitefly is expected to have significant economic and environmental impacts.  An “A”-rating is justified.

References:

1 Zlotina, Marina 2013.  Deregulation Evaluation of Established Pests (DEEP); DEEP Report on Aleurodicus dispersus Russell: Spiralling Whitefly

2 USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD).  https://pcit.aphis.usda.gov/pcit/


Responsible Party:

Jason Leathers, 1220 N Street, Sacramento, CA, 95814, (916) 654-1211, plant.health[@]cdfa.ca.gov.


Comment Period:  CLOSED

The 45-day comment period opens on Jun 22, 2016 and closed on Aug 6, 2016.


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

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 RATING PROPOSALS:

⇒ BLATTODEA

Three-lined Cockroach | Luridiblatta trivittata
Proposed Pest Rating: C
Comment Period: 1/5/18 – 2/19/18

COLEOPTERA

Ambrosia Beetle |  Xylosandrus amputatus (Blandford)
Proposed Pest Rating: A
Comment Period: 1/11/18 – 2/25/18

Banded Elm Bark Beetle | Scolytus schevyrewi Semenov
Proposed Pest Rating: C
Comment Period: 1/16/18 – 3/2/18

A Bark Beetle | Pycnarthrum hispidum (Ferrari)
Proposed Pest Rating: C
Comment Period: 1/16/18 – 3/2/18

Bark Beetle | Coccotrypes rutschuruensis Eggers
Proposed Pest Rating: A
Comment Period: 1/16/18 – 3/2/18

Black Pine Bark Beetle | Hylastes ater (Paykull)
Proposed Pest Rating: A
Comment Period: 1/17/18 – 3/3/18

Camphor Shot Borer | Cnestus mutilatus (Blandford)
Proposed Pest Rating: A
Comment Period: 1/11/18 – 2/25/18

Hylesinus cingulatus Blandford
Proposed Pest Rating: A
Comment Period: 1/17/18 – 3/3/18

Small Spruce Bark Beetle | Polygraphus poligraphus (L.)
Proposed Pest Rating: A
Comment Period: 1/16/18 – 3/2/18

Strangulate Weevil | Trochorhopalus strangulatus (Gyllenhal)
Proposed Pest Rating: A
Comment Period: 1/11/18 – 2/25/18

 HEMIPTERA

Armored Scale | Melanaspis leivasi (Costa Lima)
Proposed Pest Rating: A
Comment Period: 12/12/17 – 1/26/18

Gray Sugarcane Mealybug | Trionymus boninsis (Kuwana)
Proposed Pest Rating: A
Comment Period: 1/5/18 – 2/19/18

A Mealybug | Nipaecoccus floridensis Beardsley
Proposed Pest Rating: A
Comment Period: 1/17/18 – 3/3/18

PEST RATINGS:

COLEOPTERA

Beetle: Dactylotrypes longicollis (Wollaston)
Pest Rating: C

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

Coffee Bean Weevil | Araecerus fasciculatus
Pest Rating: B

Diaprepes Root Weevil | Diaprepes abbreviatus
Pest Rating: B

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

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

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

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

Seed Beetle | Bruchidius terrenus
Pest Rating:  B

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

Sri Lankan weevil | Myllocerus undecimpustulatus undatus
Pest Rating:  A

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

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

Velvet Longhorn Beetle: Trichoferus campestris Faldermann
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

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

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

Balsam Woolly Adelgid |  Adelges piceae
Pest Rating: B

Banana Mealybug:  Pseudococcus elisae Borchsenius
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

Citrus Snow Scale:  Unaspis citri Comstock
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

Elongate Hemlock Scale: Fiorinia externa Ferris
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

Green Scale: Coccus viridis
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

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: 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

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

Papaya Mealybug | Paracoccus marginatus Williams and Granara de Willink
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

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

Taro Planthopper: Tarophagus colocasiae
Pest Rating: B

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

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

Waratah Scale: Pseudaulacaspis brimblecombei Williams
Pest Rating:  A

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

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

HYMENOPTERA 

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

Asian Needle Ant | Brachyponera chinensis
Pest Rating: A

Bigheaded Ant: Pheidole megacephala
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

⇒ LEPIDOPTERA

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

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

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

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

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


EARTHWORMS | ANNELIDA

Asian Crazy Worm | Amynthas agrestis
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 AND PROPOSALS:

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

Ditylenchus destructor Thourne, 1945
Pest Rating: A

Helicotylenchus spp.
Pest Rating: C

Helicotylenchus multicinctus
Pest Rating:  B

Hemicycliophora arenaria
Pest Rating: B

Heterodera carotae Jones, 1950
Pest Rating: B

Longidorus elongatus: Needle nematode
Pest Rating:  B

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

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

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:

Fungi:

Diaporthe pseudophoenicicola
Current Pest Rating: Q
Proposed Pest Rating: C
Comment Period: 12/29/17 – 2/12/18

Virus

Cucumber Green Mottle Mosaic Virus
Current Pest Rating: A
Proposed Pest Rating: A
Comment Period: 1/4/18 – 2/18/18


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 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 fructicola
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

Diaporthe pseudomangiferae
Pest Rating: C

Diaporthe vaccinii
Pest Rating: C

Didymella bryoniae
Pest Rating: B

Erysiphe aquilegiae
Pest Rating: C

Fusarium brachygibbosum
Pest Rating: C

Ganoderma adspersum
Pest Rating: B

Geosmithia pallida
Pest Rating: C

Greeneria uvicola
Pest Rating: B

Kweilingia divina
Pest Rating:  A

Melampsoridium hiratsukanum: Alder Rust
Pest Rating: C

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

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:

Bamboo Mosaic Virus (BaMV)
Pest Rating: B

Cucurbit Yellow Stunting Disorder Virus
 Pest Rating:  B

Freesia Mosaic Virus
Pest Rating: B

Freesia Sneak Virus
Pest 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 Chlorotic Dwarf Viroid
Pest Rating:  A

Tomato Mottle Mosaic Virus
Pest Rating:  B

Tomato Yellow Leaf Curl Virus
Pest Rating:  B