Tag Archives: C-Rated Pest

C-Rated, Nematodes

Ditylenchus dipsaci (Kühn, 1857) Filipjev, 1936

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

 

PEST RATING PROFILE
Initiating Event: 

None. The current rating and status of Ditylenchus dipsaci in California are re-evaluated.

History & Status:

Background:  During the 1920s, the stem and bulb nematode was one of the earliest nematodes known to affect garlic and narcissus production in California where it continues to be a major pest of garlic, onion and alfalfa (Siddiqui, 1973). In alfalfa, damage is most severe in moist, cool weather in cooler, sprinkler-irrigated inland valley and foggy coastal areas of California, and the nematode may be found as far south in the Central Valley as Madera County (Westerdahl, 2007).  Ditylenchus dipsaci, the stem and bulb nematode, is one of the most devastating plant parasitic nematodes on a wide range of plants and is distributed worldwide especially in temperate regions.  It is a migratory endoparasitic nematode that feeds and inhabits mostly aerial parts of host plants (stems, leaves, inflorescence, seeds) but also invades below ground modified parts (bulbs, tubers, stolons, rhizomes and rarely roots).  Ditylenchus dipsaci has been documented in early reports as a complex containing several species (Sturhan and Brzeski, 1991).  However, D. dipsaci sensu stricto can now be distinguished from other related species by host plant range, chromosome number, morphometric values and gene sequences (Subbotin et al., 2005).

Disease cycle: D. dipsaci completes a life cycle from egg to egg in about 21 days at 59°F and a female lays 200-500 eggs within garlic and onion tissue, and egg development occurs between 59 and 70°F (Becker and Westerdahl, 2018).  Several generations can occur over one growing season. Under favorable moisture and temperature conditions, preadults become active, swim in films of water in soil or on wet plant surfaces, and attack a germinating seed or seedling entering near the root cap or within the seed. Nematodes remain intercellular and feed on parenchymatous tissue causing cell division and enlargement.  In young plants, the nematodes enter leaves through stomata or directly through the epidermis in leaf bases – resulting in cell enlargement, disappearance of chloroplasts, and increase in intercellular spaces.  As bulbs enlarge, the nematodes move down the leaves intercellularly or on the surface of leaves and re-entering at the outer sheaths of the stem or neck to infect the outer scales of bulbs.  Middle lamellae of cells and cells break down forming large cavities and stems lose their rigidity and collapse. Nematodes continue to feed through the parenchymatous outer scales.  The macerated tissue has a white mealy texture but soon turn brown due to secondary invasion.  In early stages the nematodes remain within individual scales causing complete or incomplete rings of frosty white or brown tissue.  Later, the nematodes infect more scales even after harvest and in storage usually resulting in totally infecting a bulb.  When heavily infected bulbs decay, preadults exit and accumulate about the basal plates of dried bulbs as cottony masses called “nematodes wool” and can survive there for years (Agrios, 2005; Westerdahl and Becker, 2018).  Survival: The pre-adults or fourth stage larvae can survive freezing or extreme dry conditions in anhydrous state for long periods in plant tissue, stems, leaves, bulbs, seeds or in soil (Agrios, 2005).

Dispersal and spread:  Infested plant material including bulbs, stems, leaves, and seeds; infested soil, contaminated cultivation tools and equipment, contaminated irrigation and splash water.

Hosts: There are more than 500 plant species in over 40 angiosperm families that are known to be hosts of D. dipsaci.  Many of the biological races of D. dipsaci have limited host ranges (EPPO, 2008).  In California, D. dipsaci is an important nematode pest particularly of onion, garlic, and alfalfa.

Symptoms: Emergence of infected onion seedlings is retarded, with reduced stands, appearing pale green to yellow, twisted and arched and collapsed.  Most infected seedlings die within three or more weeks.  Developing plants exhibit stunting, light yellow or brown spots, swellings (spikkles) and open lesions, swollen and deformed stems, thickened, curled, distorted leaves, collapse of leaves and premature drying and defoliation; and bloated tissue with a spongy appearance, leaf tips often exhibit a gray to brown dieback.  Older plants may also die before harvest.

Bulb tissue begins softening at the neck and gradually proceeds downwards.  Young bulbs are soft, swollen and malformed, and exhibit a coarse-textured tissue beneath the outer scale.  Bulb scales appear pale gray, soft, and loose.  Bulb tissue underneath the loose outer scales is soft, puffy, mealy and frosty in appearance.  Affected scales appear as discolored rings in cross sections of infected bulbs, and as irregular, discolored lines in longitudinal sections.  Individual cloves or, in severe cases, larger areas of the bulb become affected.  Bulbs may split, become malformed, or produce sprouts and double bulbs.  Under dry conditions bulbs become desiccated, light in weight, odorless, and split at the base.  Basal plate and roots of severely infested bulbs may also appear to a have a dry rot and can be easily separated from the bulbs, mimicking symptoms of Fusarium basal plate rot.   Under moist conditions, secondary invaders set in and bulbs rots and decay.  In storage, bulbs decay (EPPO, 2008).

Carrots and sugar beet: The plant is most affected at 2-4 cm below and above ground level.  Early symptoms include straddled (collapsed on both sides) leaves, multi-bud plant crowns and light discoloration of taproot tops (EPPO, 2008).

Alfalfa:  Nematodes enter bud tissue and developing buds.  Infected stems are enlarged, discolored – later may turn black as nematode numbers increase, swollen nodes, shortened internodes (stunted). Infected plants have fewer shoots, and deformed buds.   White or pale flags (destruction of chloroplasts) are formed as nematodes move to leaf tissue (EPPO, 2008).

Seeds:  Small seed generally show no symptoms of infestation, but the skin of larger seeds, (Phaseolus vulgaris, Vicia faba), may be shrunken with discolored spots (EPPO, 2008).

Damage Potential: If not controlled, the stem and bulb nematode has the potential to affect host crop production by reducing yield and quality, increasing costs of nematode-free production, and management options.  The seedborne capability of D. dipsaci would impact international trade of host seed and planting stock, if the latter were found infested with the nematode. However, California’s Seed Certification Program that ensures the use of clean, nematode-free seeds, has provided California garlic growers a strong preventive measure against the stem and bulb nematode.

Worldwide Distribution: Asia: Armenia, Azerbaijan, China, Republic of Georgia, India, Iran, Iraq, Israel, Japan, Jordan, Kazakhstan, Republic of Korea, Kyrgyzstan, Oman, Pakistan, Syria, Taiwan, Turkey, Uzbekistan, Yemen; Africa: Algeria, Kenya, Morocco, Nigeria, Réunion, South Africa, Tunisia; Europe: Albania, Austria, Belarus, Belgium, Bosnia-Hercegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Czechoslovakia (former), Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Macedonia, Malta, Moldova, Netherlands, Norway, Poland, Portugal, Romania, Russian Federation, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, United Kingdom, Ukraine, Yugoslavia; North America: Canada, Mexico, USA; Central America and Caribbean: Costa Rica, Dominican Republic, Haiti; South America: Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru, Uruguay, Venezuela; Oceania: Australia, New Zealand (CABI, 2018).

In the USA it has been reported from several states including: Alabama, Arizona, California, Colorado, Hawaii, Idaho, Michigan, Minnesota, Montana, Nevada, New Hampshire, New York, North Carolina, Ohio, Oregon, South Dakota, Utah, Virginia, Washington, Wyoming (CABI, 2018).

Official Control: Currently, D. dipsaci is on the ‘Harmful Organism Lists’ for 50 countries including:  Algeria, Antigua and Barbuda, Bangladesh, Brazil, Canada, Chile, China, Cook Islands, Costa Rica, Cuba, Egypt, El Salvador, European Union, French Polynesia, Georgia, Grenada, Guatemala, Holy See (Vatican City State), Honduras, India, Indonesia, Israel, Jordan, Lebanon, Madagascar, Mexico, Monaco, Morocco, Namibia, New Caledonia, New Zealand, Nicaragua, Norway, Panama, Paraguay, San Marino, Serbia, South Africa, Sri Lanka, Taiwan, United Republic of Tanzania, Thailand, Timor-Leste, Tunisia, Turkey, Uganda, United Arab Emirates, Uruguay, Viet Nam, and Yemen   (USDA PCIT, 2018).

California Distribution: Ditylenchus dipsaci is widely distributed in California.

California Interceptions:  None.

The risk Ditylenchus dipsaci would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Ditylenchus dipsaci is already widespread within California. The state provides suitable hosts and climate for the establishment and spread of dipsaci to uninfected sites.

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: Ditylenchus dipsaci has a very wide host range comprising more than 500 plant species in over 40 angiosperm families. The species also has several biological races which have limited host ranges.  In California, dipsaci is an important nematode pest particularly of onion, garlic, and alfalfa.

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: The nematode is dispersed artificially mainly through Infested plant material including bulbs, stems, leaves, and seeds; infested soil, contaminated cultivation tools and equipment, contaminated irrigation and splash water.  The ability to survive anhydrously over adverse environmental conditions particularly within plant seed and infested planting stock enables dipsaci for long distance movement over extends periods of time.

Evaluate the natural and artificial dispersal potential of the pest.

Score: 2

– 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.

Economic Impact: If left unmanaged, the stem and bulb nematode has the potential to affect host crop production by reducing yield and quality, changing normal cultural practices including supply of irrigation water to field grown crops, and increasing costs of nematode-free production. The seedborne capability of dipsaci would impact international trade of host seed and planting stock, if the latter were found infested with the nematode. However, California’s Seed Certification Program that ensures the use of clean, nematode-free seeds, has provided California garlic growers a strong preventive measure against the stem and bulb nematode, and the use of resistant varieties is regarded the most effective control of D. dipsaci in alfalfa.

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

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

A. The pest could lower crop yield.

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

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

D. The pest could negatively change normal cultural practices.

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

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

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

Economic Impact Score: 3

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

– Medium (2) causes 2 of these impacts.

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

5) Environmental Impact: Ditylenchus dipsaci has not been reported to have significant environmental impact in California.  Home gardening and ornamental plantings are usually protected against the nematode through use of nematode-free planting materials.

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

Environment 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.

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 Ditylenchus dipsaci: 11

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

-Low = 5-8 points

–Medium = 9-12 points

-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.

Evaluation is in California.

Score: (-3)

-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 = 8

Uncertainty:  

None.

Conclusion and Rating Justification:

Based on the evidence provided above the proposed rating for Ditylenchus dipsaci is C.

References:

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

Becker, J. O. and Westerdahl, B. B.  2018. Onion and garlic nematodes. UCIPM Statewide Integrated Pest Management Program, University of California Agriculture and Natural Resources. (Updated 2/07). http://ipm.ucanr.edu/PMG/r584200111.html

CABI.  2018. Ditylenchus dipsaci full datasheet. Crop Protection Compendium.  https://www.cabi.org/cpc/datasheet/19287

EPPO.  2008.  Ditylenchus destructor and Ditylenchus dipsaci Diagnostics.  European and Mediterranean Plant Protection Organization. OEPP/EPPO Bulletin 38: 363-373.

Siddiqui, I. A., Sher, S. A., and French, A. M. 1973. Distribution of plant parasitic nematodes in California. State of California Department of Food and Agriculture, Division of Plant Industry, 324 p.

Sturhan, D., and Brzeski, M. W. 1991. Stem and bulb nematodes, Ditylenchus spp. In: Manual of Agricultural Nematology Ed. Nickle, W. R., pp.423–464. Marcel Dekker, Inc., New York (US).

Subbotin, S. A., Madani, M. Krall, E., Sturhan, D., and Moens, M. 2005. Molecular diagnostics, taxonomy, and phylogeny of the stem nematode Ditylenchus dipsaci species complex based on the sequences of the internal transcribed spacer-rDNA. Phytopathology 95: 1308-1315.

USDA PCIT.  2018.  USDA Phytosanitary Certificate Issuance & Tracking System. Retrieved July 26, 2018, 1:20:45 pm CDT.  https://pcit.aphis.usda.gov/PExD/faces/ReportHarmOrgs.jsp.

Westerdahl, B. B. 2007. Parasitic nematodes in alfalfa. In Irrigated Alfalfa Management for Mediterranean and Desert Zones. University of California Division of Agriculture and Natural Resources Publication 8297 Chapter 11.

Responsible Party:

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

Comment Period:* CLOSED

8/2/18 – 9/16/18

*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.

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;

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♦  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: C

 

Posted by ls 

 

C-Rated, Insects, Mites & Earthworms, Lepidoptera

Azalea Leafminer | Caloptilia azaleella (Brants)

California Pest Rating for
Caloptilia azaleella (Brants):  Azalea leafminer
Lepidopetera:  Gracillariidae
Pest Rating: C

 

PEST RATING PROFILE

Initiating Event:

Gracillariidae insects were recently intercepted by CDFA through high risk pest exclusion program on a shipment of azalea plants, originating from Kentucky. The most common Gracillariidae, intercepted on Azalea is Caloptilia azaleella. This insect has been previously rated C by CDFA. A pest rating proposal is required to evaluate the current rating for this species.

History & Status:

Background:  Caloptilia azaleella are small, yellow moths with purplish markings on the wings. Leaf mining stage is a yellowish caterpillar about half inch long. Caloptilia azaleella is known to attack only azaleas (Rhododendron spp.) worldwide. The larvae mine the leaf tissue; as these mines age, they cause brown blisters on the leaves. The mature larvae emerge from leaf tissue, then roll and tie the edge of the leaves around themselves for protection. They can cause considerable damage to greenhouse grown azaleas in North Carolina (Frank, 2016). Maximum infestation in Florida nurseries was noted from early spring through summer (Dekle, 2007). In Oregon, where it has been  introduced, there are three generations per year.

Worldwide Distribution:

Caloptilia azaleella is endemic to Japan but has been introduced to all azalea growing parts of the world including Europe (southern Britain), New Zealand and eastern Australia (T.E.R.R.A.I.N, 2018).

In the North America, it has been found in the Unites States and Canada from Florida to Texas, Long Island, West Virginia and Ohio, California, Washington and British Colombia (Johnson and Lyon, 1994).

Official Control: Caloptilia azaleella has been listed as harmful organism in Chile (USDA -PCIT).

California Distribution:  Caloptilia azaleella was introduced to California in 1962 for the first time (Essig Museum Online Database, 2010) and more recently observed in Sonoma county (2017) and Shasta county (2014) (iNaturalist, 2016).

California Interceptions:  Caloptilia azaleella has been intercepted through high risk pest exclusion and interior quarantine programs in California (Pest and Damage Report Database, 2018).

The risk Caloptilia azaleella ( azalea leaf miner) would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Rhododendron spp. grow best in filtered shade and prefer acidic soils with high organic content and excellent drainage (Pests in garden and Landscapes, 2017). This type of climate is found in northern California and extends down the coast to San Francisco Bay (American Rhododendron Society, 2018). Some of the maddenii-type rhododendron can grow in southern California as well. Since C. azaleella is already introduced and present in Northern CA, its introduction and spread to the rest of the state is likely. It receives a Medium (2) in this category.

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: Caloptilia azaleella feeds only on Rhododendron spp. It receives a Low (1) in this category

Evaluate the host range of the pest:

Score: 1

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

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

3) Pest Dispersal Potential: Caloptilia azaleella deposits 1-5 eggs on the undersurface of leaves during spring time. The life cycle is completed in one week. It overwinters as a last instar larva or pupa in a rolled leaf. Larva can be found on leaves all year around. There are three generations in western states and three to four generations in southern states. Because azaleella does not leave its host during the entire life cycle, it does not spread over large distances. However, movement of infected azalea nursery stock could likely disperse this species. It receives a Medium (2) in this category.

Evaluate the natural and artificial dispersal potential of the pest:

Score: 2

– 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: Caloptilia azaleella is a pest of container and field grown nursery stock but can also attack landscape grown plants. Heavy infestation may not kill the plant, especially if it can be controlled during early stages of growth but the damage is likely to affect the appearance and quality of the plant. Increased cost of pruning of infested branches and release of parasitoids can add to production costs and decrease the value of the crop (Dekle, 2007). It receives a Medium (2) in this category.

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

Economic Impact: A, B, 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.

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: Caloptilia azaleella is not likely to lower biodiversity and disrupt any natural habitats. It has also not been reported to affect any endangered species, either directly or indirectly. It could attack native rhododendron and native azaleas but unlikely to cause significant damage. The infestations of azaleas would likely trigger chemical treatments by homeowners. It receives a Medium (2) in this category.

Evaluate the environmental impact of the pest on 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 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:

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 Caloptilia azaleella (azalea leaf miner): Medium (10)

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: Caloptilia azaleella (azalea leafminer) has been found in the environment and receives a Low (-1) 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: -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:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (9)

Uncertainty:

Caloptilia azaleella is present in azalea growing areas in Northern California and has also been detected by CDFA from time to time. However, it is not widespread in the state, possibly due to its inability to attack any other host plants. There are some varieties of Rhododendron, being grown in Southern CA and it may be present in large azalea growing areas than is currently known

Conclusion and Rating Justification:

Caloptilia azaleella has been reported in the environment of California. However, it is not likely to have significant economic and environmental impacts. A “C” rating is justified.

References:

 American Rhododendron Society (ARS): California Chapter, 2018. Plant Culture and Care. P.O. Box 214, Great River, NY 11739. Accessed 6/14/2018: http://www.rhododendron.org/climate.htm http://www.calchapterars.org/

Dekle, G.W. 2007. Azalea Leaf miner: Featured Creatures. Entomology and Plant Pathology. Publication # EENY-379, Florida Department of Agriculture and Consumer Services, Division of Plant Industry, University of Florida. Accessed 6/14/2018:  http://entnemdept.ufl.edu/creatures/orn/shrubs/azalea_leafminer.htm

Essig Museum Online Database, 2010. California Moth Specimen Database. University of California, Berkeley. Accessed 6/21/2018  https://essigdb.berkeley.edu/calmoth.html

Frank, S. 2016. Azalea leafminer. Entomology Insect Notes. North Carolina State Extension Publications North Carolina State Extension. Accessed 6/14/2018:  https://content.ces.ncsu.edu/azalea-leafminer

iNaturalist, 2016. Online crowdsourced species identification system and an organism occurrence recording tool. Gracillariidae of California. Caloptilia azaleella  https://www.inaturalist.org/observations?locale=en-US&place_id=14&taxon_id=320764

Johnson WT and Lyon HH. 1994. Insects That Feed on Trees and Shrubs. 2nd ed. rev. Cornell University Press, Ithaca, NY.

Pest and Damage Report Database, 2018. Caloptilia azaleella. Plant Health and Pest Prevention Services. California Department of Food and Agriculture. Accessed 6/14/2018:  http://phpps.cdfa.ca.gov/user/frmLogon2.asp

Pests in gardens and landscapes, 2017. Azalea-Rhododendron spp. Agriculture and Natural Resources, University of California. Statewide Integrated Pest Management Program. Accessed 6/15/2018: http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/azalea.html

Reding, Tom. 2018. Caliptilia azaleella. Wikipedia- the free encyclopedia. Accessed 6/19/2018:  https://en.wikipedia.org/w/index.php?title=Caloptilia_azaleella&oldid=825762750#References

Richers, K. 1996. California Moth Specimens Database. Caloptilia azaleella. University of California, Berkeley. Accessed 6/21/018. https://essigdb.berkeley.edu/calmoth_about.html

Taranaki Educational Resource: Research, Analysis and Information Network. (T.E.R.R.A.I.N.), 2018. “Caloptilia azaleella (Azalea leafminer moth)”. The MAIN trust GIS community project. Government of New Zealand. Accessed 6/14/2018: http://www.terrain.net.nz/friends-of-te-henui-group/moths/caloptilia-azaleella-moth-azalea-leafminer-caloptilia-azaleella.html

USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Harmful organism report: Caloptilia azaleella. Accessed 6/14/2018.  https://pcit.aphis.usda.gov/pcit/

Author:

Raj Randhawa, 1220 ‘N’ Street, Room 221, Sacramento CA 95814, (916) 403-6617, plant. health[@]cdfa.ca.gov

Responsible Party:

Jason Leathers, 2800 Gateway Oaks, Sacramento CA 95833, (916) 654-1211, plant.health[@]cdfa.ca.gov

Comment Period:* CLOSED

7/30/18 – 9/13/18

*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.

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: C

 

Posted by ls 

C-Rated, Coleoptera, Insects, Mites & Earthworms

Weevil | Oxydema longula (Boheman)

California Pest Rating  for
Weevil | Oxydema longula (Boheman)
Coleoptera: Curculionidae
Pest Rating: C

 

PEST RATING PROFILE

Initiating Event:

Oxydema longula is currently Q-rated.  A permanent pest rating proposal is required to support an official pest rating.

History & Status:

Background:  Oxydema longula is a weevil that measure 5-5.5 mm in length and is black and shining (Boheman, 1859).  The species occurs in a variety of dead and decaying plant material, and the larvae are reported to feed in dead ferns and bamboo and rotting wood (Blackburn and Sharp, 1887; Swezey, 1922; Swezey, 1925; Swezey, 1954).  This weevil has been reported to be associated with living plants as well.  For example, it bored into rubber trees and “matured” sisal plants and “riddled” a papaya tree in Hawaii (Kuhns, 1908; Smith and Bradford, 1908; Van Dine, 1906).  The species has also been intercepted on cordyline (Hunt, 1954).  These records do not necessarily indicate that this weevil attacks living plant tissue.  The boring in rubber trees occurred in rubber tapping injuries.  Regarding the sisal plant records, this plant is harvested via removal of older leaves, so the burrowing of the weevil could have exploited dead tissue resulting from harvesting injuries.  The weevil(s) intercepted on cordyline could simply have been using the plant as shelter, or it could have been feeding on a dead portion of the plant.

Little information was found on the biology of the genus Oxydema, but Oxydema fusiforme Wollaston is reported to feed on rotting plant material, including rotting wood and boards and dead morning glory vines (Hawaiian Entomological Society, 1922; Hawaiian Entomological Society, 1935; Loschiavo and Okumura, 1979).

Synonyms of Oxydema longula include Oxydema longulum (Boheman), Oxydema longulus (Boheman), Pseudolus longulus (Boheman), and Rhyncolus longulus Boheman.  Information reported for these synonyms was considered in this proposal.

Worldwide Distribution:  Oxydema longula is reported from Hawaii (all islands), Midway Atoll, and Saipan Island (Konishi, 1956; Suehiro, 1960; Zimmerman, 1940).  It may be native to Hawaii and introduced to the other areas.

Official Control: Oxydema longula is not known to be under official control anywhere.

California Distribution:  Oxydema longula is not known to be present in California.

California Interceptions:  Oxydema longula has been intercepted 12 times on various plant products from Hawaii, including cut flowers (CDFA Pest and Damage Report Database, 2018).

The risk Oxydema longula would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Oxydema longula is found in areas with a tropical to subtropical climate. Climate may limit this weevil’s potential distribution in California.  This weevil apparently feeds on a wide variety of decaying plant material.  Presence of food is not expected to be a limiting factor in its potential distribution in California. Therefore, Oxydema longula receives a Medium (2) in this category.

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: Oxydema longula is reported to feed on a wide variety of rotting plant material. Therefore, it receives a High (3) in this category.

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: Another species of Oxydema, fusiforme, was collected at light in Hawaii, so it presumably flies (Browne, 1942).  Oxydema longula is presumed to fly as well.  Therefore, it receives a Medium (2) in this category.

Score: 2

– 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: Oxydema longula has not been reported to cause economic damage.  The available evidence strongly suggests that it feeds on dead, rotting plant material.  Therefore, it receives a Low (1) in this category.

Economic Impact:

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: Oxydema longula apparently feeds on dead plant material. The species is therefore not expected to threaten living plants.  However, it could compete with native insects that also feed on dead plant material.  Therefore, it receives a Medium (2) in this category.

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

Environmental Impact:  A

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:

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 Oxydema longula: Medium (10)

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: Oxydema longula is not known to be present in 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:

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

Uncertainty:

There is a possibility that O. longula may feed on living plant tissue, although the available reports generally state dead (often rotting) plant material as the food.

Conclusion and Rating Justification:

Oxydema longula is a weevil that is reported to feed on dead plant material.  This saprophagous lifestyle suggests that it does not pose an economic or environmental risk to California.  For these reasons, a “C” rating is justified.

References:

Blackburn, T. and Sharp, D.  1885.  Memoirs on the Coleoptera of the Hawaiian Islands.  The Scientific Transactions of the Royal Dublin Society 3:119-300.

Boheman, C. H.  1859.  Coleoptera.  pp. 113-218 in Kongliga Svenska Fregatten Eugenies.  P.A. Norstedt & Söner, Stockholm.

Browne, A. C.  1942.  Insects taken at light at Kalawahine Place, Honolulu.  Proceedings of the Hawaiian Entomological Society 11:151-152.

CDFA Pest and Damage Report Database.  2018.  Oxydema longula.  Plant Health and Pest Prevention Services. CA Department of Food and Agriculture.  Accessed April 16, 2018: https://pdr.cdfa.ca.gov/PDR/pdrmainmenu.aspx

Hawaiian Entomological Society.  1922.  November 3, 1921.  Proceedings of the Hawaiian Entomological Society 5:32-35.

Hawaiian Entomological Society.  1935.  April 5, 1934.  Proceedings of the Hawaiian Entomological Society 5:12-16.

Hunt, J.  1954.  List of intercepted plant pests, 1954.  United States Department of Agriculture.

Konishi, M.  1955.  Cossoninae of Marcus Island.  Insecta Matsumurana 19:64.

Kuhns, D. B.  Noted on Maui insects.  Proceedings of the Hawaiian Entomological Society 2:93.

Loschiavo, S. R. and Okumura, G. T.  1979.  A survey of stored product insects in Hawaii.  Proceedings of the Hawaiian Entomological Society 13:95-118.

Smith, J. G. and Bradford, Q. Q.  1908.  The ceara rubber tree in Hawaii.  Bulletin of the Hawaii Agricultural Station 16:1-30.

Suehiro, A.  1960.  Insects and other arthropods from Midway Atoll.  Proceedings of the Hawaiian Entomological Society 17:289-298.

Swezey, O. H.  1922.  Insects attacking ferns in the Hawaiian Islands.  Proceedings of the Hawaiian Entomological Society 5:57-65.

Swezey, O. H.  1925.  The insect fauna of trees and plants as an index of their endemicity and relative antiquity in the Hawaiian Islands.  Proceedings of the Hawaiian Entomological Society 6:195-209.

Swezey, O. H.  1954.  Forest entomology in Hawaii.  Bernice Bishop Museum Special Publication 44:1-265.

Symbiota Collections of Arthropods Network.  Accessed April 27, 2018. http://scan1.acis.ufl.edu

Van Dine, D. L.  1906.  Report of the entomologist.  Report on Agricultural Investigations in Hawaii 1906:38-59.

Zimmerman, E. C.  1940.  Synopsis of the genera of Hawaiian Cossoninae with notes on their origin and distribution.  Occasional Papers of Bernice P. Bishop Museum, Honolulu, Hawaii 15:271-293.

Author:

Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741; plant.health[@]cdfa.ca.gov.

Responsible Party:

Jason Leathers, 2800 Gateway Oaks, Sacramento CA 95833, (916) 654-1211, plant.health[@]cdfa.ca.gov

Comment Period:* CLOSED

7/3/18 – 8/17/18

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Pest Rating: C

 

Posted by ls