Tag Archives: C-Rated Pest

Ilyonectria capensis L. Lombard & Crous 2013

California Pest Rating Proposal

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


Comment Period:  2/22/2019 – 4/8/2019*


Author/Responsible Party:

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


*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.


Proposed Pest Rating: C


Posted by ls 

Field Bindweed | Convolvulus arvensis L.

California Pest Rating for
Convolvulus arvensis L.: Field bindweed
Family:  Convolvulaceae
Pest Rating: C | Proposed Seed Rating: R

PEST RATING PROFILE

Initiating Event:

Convolvulus arvensis is currently C-rated. A pest rating proposal is required to support an official pest rating based on current information.

History & Status:

Background: Convolvulus arvensis is a deep-rooted perennial herb with prostrate stems. The leaves are hairless and obovate with a notched base, and they reach up to 7.5 cm long and 3 cm wide. The flowers are trumpet shaped, white to pink in color, and 2.5 cm to 3.8 cm inches wide. Reports indicate that seeds of this species can persist in soil for up to 60 years and the roots are reported to grow up to 30 feet deep (Appleby, 1999).  It is a highly invasive garden and agricultural weed that difficult to eradicate. It is also found in other habitats, including wooded areas.

Worldwide Distribution: Convolvulus arvensis is native to Eurasia and has been introduced widely to temperate and tropical regions throughout the world. It may be found between 60°N and 45°S latitude (Discover Life, 2016).    

Official Control: Convolvulus arvensis is listed as a harmful organism in Australia, Ecuador, Honduras, Nauru, Nicaragua, and Taiwan. It is listed as a noxious weed in Alaska, Arizona, Arkansas, Hawaii, Idaho, Iowa, Kansas, Michigan, Minnesota, Missouri, Montana, North Dakota, South Dakota, Texas, Utah, Wisconsin, Wyoming, California, Colorado, New Mexico, and Oregon.

California Distribution: Convolvulus arvensis was first reported in California in 1850 in San Diego (CalFlora 2018, CCH 2018). It has since spread, and it is documented from all counties in California except Del Norte.

California Interceptions: Convolvulus arvensis has been intercepted 123 times from 2003 through September 2018 by CDFA. These interceptions were mostly through seed certification program and general botany surveys (PHPPS- PDR Database).

The risk Convolvulus arvensis (field bindweed) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Convolvulus arvensis has become widely established throughout California, so it has demonstrated that the climates and habitats found in the state are conducive to its establishment. This plant can grow in nurseries, crops, vineyards, and range land. Therefore, it receivesHigh (3) 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: Convolvulus arvensis does not require any one host, but grows wherever ecological conditions are favorable. It receives a High (3) in this category.

Evaluate the host range of the pest.

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

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

3) Pest Dispersal Potential: Convolvulus arvensis spreads by seed and sprouted rhizomes and roots. Each plant produces up to 500 seeds that can be viable in the soil for up to 20 or more years. These seeds can be dispersed by birds, water, and contaminated farm vehicles. The most common dispersal method of this weed is the use of contaminated seed stocks in Commerce. 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.

  1. Economic Impact: Convolvulus arvensis grows rapidly and competes with native vegetation and agricultural crops. Yield reductions of 20-80% have been reported in annual crops, including cereals and grain legumes (Phillips and Timmons, 1954; Black et al., 1994). Convolvulus arvensis can impede harvesting of annual crops because the crop becomes entangled with the twining stems of this plant. The heavy infested foliage contains alkaloids that can cause intestinal problems in horses (Todd et al., 1995). It 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, D, F

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: Convolvulus arvensis can compete with native vegetation for nutrients, moisture, space, and light, which could decrease the biodiversity of infested areas in California. Infestations of this plant could trigger additional private treatment programs in infested areas. It receives a High (3) in this category.

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

Environmental Impact:  A, 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 Convolvulus arvensis (Field bindweed): High (15)

Low = 5-8 points

-Medium = 9-12 points

-High = 13-15 points

6) Post Entry Distribution and Survey Information: Convolvulus arvensis is fully established and widespread in California. 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.   

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (12)

Uncertainty:

Convolvulus arvensis has been in California for over 120 years and it has become established in every county except Del Norte, although in limited areas. Therefore, it is little uncertainty associated with this assessment.

Conclusion and Rating Justification:

Based on the score listed above, Convulvulus arvensis is medium risk.  It will continue to spread, but it is already widespread through the state. Because it is so widespread in California, a “C” rating is recommended.


References:

Appleby, A.  1999. Field bindweed (Convolvulus arvensis).  Accessed September 19, 2018.
http://www.css.orst.edu/newsnotes/9903/weed.html#Field Bindweed

CABI Crop Protection Compendium online data sheet. Convolvulus arvensis (bindweed). CABI Publishing 2011. Accessed September 18, 2018
https://www.cabi.org/isc/datasheet/15101

CalFlora: Information on California plants for education, research and conservation.  Accessed September 18, 2018.
http://www.calflora.org/

Consortium of California Herbaria [CCH], 2018. Data provided by the participants of the Consortium of California Herbaria. Regents of the University of California. Accessed September 2018.  http://ucjeps.berkeley.edu/consortium/.

Phillips, W. and Timmons, F. 1954. Bindweed – how to control it. Bulletin 366, Fort Hays Branch, Kansas Agricultural Experimental Station, Manhattan, Kansas, USA.

Pest and Damage Record Database, California Department of Food and Agriculture, Plant Health and Pest Prevention Services. Accessed September 18, 2018. http://phpps.cdfa.ca.gov/user/frmLogon2.asp

University of California Agriculture and Natural Resources. Accessed September 18, 2018.
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7462.html

Todd, F. G., Stermitz, F. R., Schultheis, P., Knight, A. P., and Traub-Dargatz, J. L. 1995. Tropane alkaloids and toxicity of Convolvulus arvensis. Phytochemistry 39:301-303.

USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). Accessed September 19, 2018.
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

Responsible Party:

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


Comment Period:*CLOSED

11/29/2018 – 1/13/2019


*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 | Proposed Seed Rating: R


Posted by ls 

Cercospora insulana Sacc. 1915

California Pest Rating for
Cercospora insulana Sacc. 1915
Pest Rating: C

PEST RATING PROFILE

Initiating Event: 

On May 11, 2018 a postal shipment of statice dried flowers showing symptoms of leaf spots was intercepted by the CDFA at a Federal Express (FedEx) office.  The shipment was destined to a private owner in Alameda County and had originated in Hawaii.  A sample of the symptomatic flowers was sent to the CDFA Plant Pathology Lab for disease diagnoses.  On May 17, 2018 Cheryl Blomquist, CDFA plant pathologist, identified the fungus, Cercospora insulana associated with the leaf spots.  The present status and rating of C. insulana is reevaluated here.

History & Status:

Background:  Cercospora insulana is a fungal plant pathogen in the Mycosphaerellaceae family, that causes leaf spot of statice and other host plants.

The pathogen is globally widespread.  In the USA, Cercospora insulana has only been reported from Florida and California (Farr & Rossman, 2018).  In California, prior to its most recent detection, the pathogen has been reported on Armeria sp. and Limonium spp. in northern and southern coastal region of California (French, 1989).

Disease cycle: In general, plants infected with Cercospora species produce conidiophores (specialized hypha) that arise from the plant surface in clusters through stomata and form conidia (asexual spores) successively.  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.  Substomatal stroma (compact mycelial structure) may form from which conidiophores develop.  Development of the pathogen is favored by high temperatures and the disease is most destructive during summer months and warmer climates.  High relative humidity is necessary for conidial germination and plant infection.  The pathogen can overwinter in or on seed and as mycelium (stromata) in old infected leaves (Agrios, 2005).   

Dispersal and spread: Dispersal and spread: air-currents, infected nursery plants, infected leaves, seeds (Agrios, 2005).

Hosts: Armeria sp., A. maritima (thrift seapink), Limonium sp., L. bonducellii (Algerian statice), L. californicum (California sea lavender/marsh rosemary), L. gmelinii (syn. Statice gmelinii; Siberian statice), L. sinuatum (syn. Statice sinuata; statice/wavyleaf sea lavender), L. vulgare (common sea lavender) (CABI, 2018; French, 1989); Nerium indicum (Indian oleander) (XueWen et al., 2017)

Symptoms:  Leaf spot symptoms caused by Cercospora insulana in field-grown statice were reported from Italy as circular, brown lesions with a darker edge, 3-6 mm in diameter and surrounded by an orange or reddish halo.  Old lesions enlarged and coalesced, causing yellowing and senescence of leaves.  Heavy infections resulted in severe defoliation and retarded growth or death in panicles. Lesions were also present on the wings of the flower scapes, while scapes proper were not involved (Nicoletti et al., 2003).

Damage Potential: Quantitative losses due to Cercospora insulana have not been reported.  If left uncontrolled, leaf spotting may lead to disease outbreaks under favorable conditions, wherein photosynthetic areas can be reduced.  Heavy infections may result in severe defoliation, retarded plant growth and death of flowers in statice, and likely, in other ornamental host plants.  Nursery productions of ornamental hosts under controlled and conducive conditions for pathogen development would also be of concern in California.  However, damage potential due to this pathogen is likely to be similar to other Cercospora diseases which is usually low (Agrios, 2005).  Furthermore, fungicide applications and sanitary measures including the use of clean seed have been used to successfully control Cercospora diseases (Agrios, 2005).

Worldwide Distribution: Asia: China (XueWen et al., 2017), India, Myanmar; Africa: Kenya, Malta, South Africa, Zimbabwe; Europe: Caucasus, Italy, Portugal, Russia: North America: USA (California, Florida), Haiti; Oceania: Australia, New Zealand (Farr & Rossman, 2018)

Official Control: Presently, Cercospora insulana is on the ‘Harmful Organism’ list for Brazil, Colombia, Ecuador and Israel (USDA PCIT, 2018).

California Distribution:  Cercospora insulana is distributed in northern and southern coastal areas of the State (French, 1989).

California Interceptions To date, the recent detection of C. insulana (see ‘initiating event’) has been the only interception reported.

The risk Cercospora insulana would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Cercospora insulana has only been detected in northern and southern coastal regions in California. These limited regions provide adequate moisture that favor development of the pathogen in host plants like statice.

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: The known host range is limited to statice, thrift seapink and Indian oleander in the genera Limonium, Armeria and Neria.

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: Cercospora insulana has high reproductive potential resulting in the successive production of conidia which primarily depend on air currents, infected plants and seed for dispersal and spread.

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: Quantitative losses due to Cercospora insulana have not been reported. However, for nurseries particularly, infected host plants with leaf spots could result in lowered value resulting in use of fungicidal treatments thereby increasing production costs, and loss of markets.

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

Economic Impact: 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: 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: Home garden plantings of statice species may be impacted if the pathogen was to establish under favorable environmental conditions and in the absence of adequate disease control.  The pathogen has not been detected in oleander in California.

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

Environment 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 Cercospora insulana:

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 = 10

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 ‘Medium’ in California.

Score: (-2)

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

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

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

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

Final Score:

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 Cercospora insulana is to continue as C.


References:

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

Farr, D.F., & A. Y. Rossman.  2016.  Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA.  Retrieved May 18, 2018, from http://nt.ars-grin.gov/fungaldatabases/

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).

Nicoletti, R., F. Raimo, C. Pasini, and F. D’Aquila.  2003.  Occurrence of Cercospora insulana on statice (Limonium sinuatum) in Italy.  Plant Pathology 52: 418.  DOI: 10.1046/j.1365-3059.2003.00840.x

USDA PCIT.  2018.  USDA Phytosanitary Certificate Issuance & Tracking System. Retrieved May 18, 2018. 12:45:06 pm CDT.  https://pcit.aphis.usda.gov/PExD/faces/ReportHarmOrgs.jsp.

XueWen, X., Z. Qian and G. YingLan.  2017.  New records of Cercospora and Pseudocercospora in China.  Mycosystema 36: 1164-1167.


Responsible Party:

John J. Chitambar, Primary Plant Pathologist/Nematologist, California Department of Food and Agriculture, 3294 Meadowview Road, Sacramento, CA 95832. Phone: 916-738-6693, plant.health[@]cdfa.ca.gov.


Comment Period:* CLOSED

9/13/18 – 10/28/18


*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 

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:

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Comment Format:

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

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Pest Rating: C

 


Posted by ls 

 

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:

BackgroundCaloptilia 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 DistributionCaloptilia 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 InterceptionsCaloptilia 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;

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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 

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

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Pest Rating: C

 


Posted by ls