Tag Archives: snail

Snails and Slugs

Small Pointed Snail | Cochlicella barbara (Linnaeus)

March 16, 2015 Jason Leathers

California Pest Rating for

Small Pointed Snail | Cochlicella barbara (Linnaeus)

Gastropoda: Cochlicellidae

Pest Rating: B

PEST RATING PROFILE

Initiating Event:

In February 2015 CDFA was notified of the discovery of Cochlicella barbara, small pointed snail, in Santa Clara County during the Citizen Science Association Conference BioBlitz. A pest rating proposal is required to designate a permanent pest rating for this snail.

History & Status:

Background: Cochlicella barbara is an air-breathing land snail that is considered a pest of cereal crops and pastures in Australia^1,3. Like most snails it is polyphagous and may be moved long distances when infested plants are moved or as a contaminating pest.

Worldwide Distribution: Cochlicella barbara is native to the Mediterranean region. From there it has spread to Australia, New Zealand, and South Africa.

Official Control: Cochlicella barbara is listed as a harmful organism by Chile, Japan, and the Republic of Korea².

California Distribution: Specimens in the California State Collection of Arthropods and records in the PDR Database indicate that Cochlicella barbara may have been present in California since the 1970’s. It has been found in the following locations: Santa Cruz County: Watsonville (1974), Davenport (1975), and Santa Cruz (1988 and 1993); San Diego County: Santee (1985); Santa Barbara County: Santa Barbara (2001); San Joaquin County: Tracy (2001); and Santa Clara County: Moffet Field (2007).

California Interceptions: Cochlicella barbara was intercepted once on Dracena reflexa plants imported from Florida in 2001.

The risk Cochlicella barbara poses to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Cochlicella barbara is widespread in Europe and the Mediterranean and similar climates exist in California. The snail can be expected to establish a widespread distribution in the state and receives a High (3) in this category.

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

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

2) Known Pest Host Range: Cochlicella barbara is polyphagous and receives a High (3) in this category.

Evaluate the host range of the pest. Score:

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

3) Pest Dispersal Potential: Snails are capable of rapid reproduction and can move long distances when infested plants are moved or as a contaminating pest on a wide variety of consignments. Cochlicella barbara receives a High (3) in this category.

Evaluate the natural and artificial dispersal potential of the pest. Score:

– 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: Cochlicella barbara has not had any significant economic impacts since it was first reported in California in the 1970’s. However, it is listed as a harmful organism by several other nations and has the potential to cause trade disruptions as it expands its distribution and increases in abundance. The snail has not lowered any crop yields, reduced crop values, changed cultural practices, injured animals, or interfered with water supplies. It is considered a vector of nematode-caused diseases such as sheep lungworm³. Cochlicella barbara receives a Medium (2) in this category.

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

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

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

5) Environmental Impact: Since its first reports in California in the 1970’s, no significant environmental impacts have been reported from Cochlicella barbara. The snail has not been observed to lower biodiversity, disrupt natural communities, or change ecosystem processes. It has not known to have affected any threatened or endangered species or disrupted critical habitats. It is not known to have triggered any additional treatment programs or impacted any cultural practices, home/urban gardens, or ornamental plantings. Cochlicella barbara receives a Low (1) in this category.

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

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

Score the pest for Environmental Impact. Score:

– Low (1) causes none of the above to occur.
– Medium (2) causes one of the above to occur.
– High (3) causes two or more of the above to occur.

Likely consequences of the presence of Cochlicella barbara for California: Medium (12)

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: Cochlicella barbara is only known from 9 samples of snails collected in California in Santa Cruz, San Diego, Santa Barbara, San Joaquin, and Santa Clara counties over a period of more than 40 years. It may or may not be established in these areas. It receives a Medium (-2) in this category.

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

– 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 likely consequences of introduction score minus the post-entry distribution and survey information score: Medium (10)

Uncertainty:

There have not been any recent statewide surveys for snails in California. Snails are most active at night and at low population densities are unlikely to be observed during typical daytime visual surveys for other pests. It is possible that Cochlicella barbara is more widespread in the state than is presently known. Alternatively, it may have failed to establish in some of the locations where it was found.

Conclusion and Rating Justification:

Nine samples of snails identified as Cochlicella barbara have been found in California over the last 40 years. However, the present distribution of the species is unknown. Although no significant economic or environmental impacts have yet to be reported from this snail there are potential economic impacts. A “B” rating is appropriate.

References:

¹ Baker, Geoff H. 2002. Helicidae and Hygromiidae as Pests in Cereal Crops and Pastures in Southern Australia. In: Molluscs as Crop Pests. CABI Publishing New York. 468 pp. http://www.cabi.org/bookshop/book/9780851993201

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

³ Herbert, David G. 2010. The introduced Mollusca of South Africa. South Africa National Biodiversity Institute. 109 pp. http://www.sanbi.org/sites/default/files/documents/documents/bioseries15introterrestmollusca.pdf

Responsible Party:

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

Pest Rating: B

Posted by ls

Snails and Slugs

A Hygromiid Snail | Xerotricha conspurcata (Draparnaud)

March 16, 2015 Jason Leathers

California Pest Rating for

A Hygromiid Snail | Xerotricha conspurcata (Draparnaud)

Helicoidea: Hygromiidae

Pest Rating: B

PEST RATING PROFILE

Initiating Event:

On February 2, 2015 USDA inquired as to the status of Xerotricha conspurcata in California. A pest rating proposal is required to determine future direction.

History & Status:

Background: Xerotricha conspurcata is an air-breathing snail that is predominantly detritivorous¹. High populations are reported to be problematical in vineyards and orchards¹. The snail can be moved long distances as a contaminating pest on consignments of tile and other building supplies.

Worldwide Distribution: Xerotricha conspurcata is native to the Mediterranean region of Europe². It is not known to occur outside of Europe. It might be present in Washington state¹.

Official Control: Xerotricha conspurcata is not listed as a harmful organism by any other states or nations³.

California Distribution: The only documented official specimen of Xerotricha conspurcata that might be from the environment of California was found in South San Francisco (San Mateo County) in 1998 (PDR 1117385). There are literature reports that the snail is established in four or five counties in the San Francisco Bay area⁴ but the source of these data are unknown.

California Interceptions: Xerotricha conspurcata was intercepted eight times in 1996 on rocks, Eucalyptus sp., chipped wood, concrete piling, lumber, wood, cardboard, and soil.

The risk Xerotricha conspurcata would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Xerotricha conspurcata is native to the Mediterranean region of Europe. Much of California’s climate is similar to this region. The snail is predominantly a generalist detritivore, so it is likely to encounter suitable host plants throughout the state. Xerotricha conspurcata receives a High (3) in this category.

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

2) Known Pest Host Range: Xerotricha conspurcata is primarily a detritivore but high populations may feed on plants. The snail receives a Medium (2) in this category.

Evaluate the host range of the pest. Score:

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

3) Pest Dispersal Potential: Snails have h igh reproductive rates and can be moved long distances when contaminated plants or items are moved. Xerotricha conspurcata receives a High (3) in this category.

Evaluate the natural and artificial dispersal potential of the pest. Score:

4) Economic Impact: Xerotricha conspurcata is not documented as a pest in scientific literature. There are no reports that suggest that it will lower crop yields, lower crop values, trigger losses of markets, negatively change cultural practices, vector other organisms, injure animals, or interfere with water supplies. Xerotricha conspurcata receives a Low (1) in this category.

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

– 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: Xerotricha conspurcata is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes. The snail is not expected to directly affect threatened or endangered species or disrupt critical habitats. It is not likely to trigger additional treatment programs or significantly impact cultural practices, home/urban gardening, or ornamental plantings. Xerotricha conspurcata receives a Low (1) in this category.

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

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 Common Name: 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: Xerotricha conspurcata is reported to be found in four to five counties of the San Francisco Bay area. However, this is not confirmed with official specimens. The presence of this snail in California is doubtful. The snail receives a Not established (0) in this category.

Final Score:

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

Uncertainty:

The presence of this snail in the environment of California is uncertain. There is only one official specimen collected in 1998 and the origin of that specimen is not clear. It is possible that Xerotricha conspurcata is not present in California.

Conclusion and Rating Justification:

The presence of Xerotricha conspurcata in California is doubtful. However, if it were to establish in the state it is expected to have limited economic and environmental impacts. A “B” rating is justified.

References:

¹ National Agricultural Pest Information System (NAPIS). Purdue University. “Survey Status of Hygromiid Snail – Xerotricha conspurcata (All Years).” Published: 01/27/2015. http://pest.ceris.purdue.edu/map.php?code=IGDGAYA&year=alltime. Accessed: 02/02/2015. http://pest.ceris.purdue.edu/pest.php?code=IGDGAYA

² GBIF.org http://www.gbif.org/species/4564725

³ USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). https://pcit.aphis.usda.gov/pcit/

⁴ Cowie, R.H., R.T. Dillon, Jr., D.G. Robinson, and J.W. Smith. 2009. Alien non-marine snails and slugs of priority quarantine importance in the United States: A preliminary risk assessment. American Malacological Bulletin 27: 113-132. http://www.stoppinginvasives.com/dotAsset/9d6257ee-fcf9-4e74-afce-1183466d390a.pdf

Responsible Party:

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

Pest Rating: B

Posted by ls

Snails and Slugs

Cuban Brown Snail | Zachrysia provisoria (Pfeiffer)

March 16, 2015 Jason Leathers

California Pest Rating for

Cuban Brown Snail | Zachrysia provisoria (Pfeiffer)

Gastropoda: Pleurodontidae

Pest Rating: A

PEST RATING PROFILE

Initiating Event:

Zachrysia provisoria is frequently intercepted by CDFA and is presently assigned a temporary rating of “Q”. A pest rating proposal is required to assign a permanent pest rating.

History & Status:

Background: Zachrysia provisoria is an air-breathing terrestrial snail that is considered to be a voracious pest of citrus, tropical fruits, vegetables, and most ornamental plants^1,2. It can be transported long distances when infested potted plants are moved.

Worldwide Distribution: Zachrysia provisoria is native to the Caribbean region. It was deliberately introduced to Florida in the early 1900’s and spread throughout much of the state¹. It is also found in Costa Rica¹.

Official Control: Zachrysia provisoria is not known to be listed as a quarantine pest by any other states or nations³. However, Australia, Chile, and Nauru list the entire class Gastropoda as harmful organisms³.

California Distribution: Zachrysia provisoria has never been found in the environment of California.

California Interceptions: Zachrysia provisoria was intercepted by CDFA’s high risk programs and border stations 192 times between January 1, 2000 and December 31, 2014 primarily on shipments of nursery stock from Florida. The snail has also been intercepted several times at nurseries within California.

The risk Zachrysia provisoria would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Since the snail was introduced to Florida in the early 1900’s it has spread as far north as Tampa¹. This corresponds to USDA plant hardiness zones 9b and above. This corresponds with most of coastal California, the central valley, and southern California. Zachrysia provisoria is likely able to establish throughout these regions and therefore receives a High (3) in this category.

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

2) Known Pest Host Range: Zachrysia provisoria is considered a voracious, polyphagous snail that feeds on citrus, tropical fruits, vegetables, and most ornamental plants. It receives a High (3) in this category.

Evaluate the host range of the pest. Score:

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

3) Pest Dispersal Potential: Zachrysia provisoria, like other snails, can be considered to have high reproductive potential. It is frequently transported long distances when infested plants are moved. This snail receives a High (3) in this category.

Evaluate the natural and artificial dispersal potential of the pest. Score:

4) Economic Impact: Zachrysia provisoria is likely to reduce yields within California’s nursery industry, gardens, and possibly farms by consuming crop and ornamental plants. The snail is likely to lower the value of nursery stock by disfiguring plants and contaminating them with its presence. All snails are considered quarantine pests by several of California’s trading partners. If Zachrysia provisoria were to enter California it has the potential to disrupt a wide variety of exports. Zachrysia provisoria receives a High (3) in this category.

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

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

5) Environmental Impact: If Zachrysia provisoria were to enter California it is likely that the snail will trigger chemical treatments in the nursery industry, farms and orchards, and by residents. The snail is also considered a voracious pest of most ornamental plants would be expected to significantly impact cultural practices, home/urban gardens, and ornamental plantings. Zachrysia provisoria receives a High (3) in this category.

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

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 Zachrysia provisoria (Cuban Brown Snail): High (15)

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: Zachrysia provisoria has not been found in the environment of California and receives a Not established (0) in this category.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: High (15)

Uncertainty:

There have not been any recent surveys for Zachrysia provisoria in California. Due to the large number of interceptions it is possible that some snails may have escaped detection and entered the state. Zachrysia provisoria may be present in some places in California.

Conclusion and Rating Justification:

Zachrysia provisoria has never been found in the environment of California and is likely to have significant economic and environmental impacts if it were to enter the state. An “A”-rating is justified.