A Semi-Slug | Parmarion martensi (Simroth) | Pest Rating Proposals and Final Ratings

California Pest Rating for

A Semi-Slug | Parmarion martensi (Simroth)

Gastropoda: Helicarionidae

Pest Rating: A

PEST RATING PROFILE

Initiating Event:

Parmarion martensi has been intercepted by CDFA and presently has a temporary “Q” rating. A pest rating proposal is required to determine a permanent pest rating.

History & Status:

Background: Parmarion martensi is a terrestrial semi-slug that is polyphagous on a variety of living and decaying plant material. In Hawaii a survey found the semi-slug on: green plants: lettuce, fennel, sweet potato, banana, passion fruit, lemongrass, Heliconia; fallen fruit: avocado, guava, citrus, papaya, mango; under plastic or plastic-like materials: black plastic sheeting, tarps, drainpipes, plant pots; compost and trash cans; food preparation and sink areas: outdoor sinks, dishes, grills, a toothbrush; pet food; structures: decks, walkways, walls; palm trees; catchment tanks; ripe fruit: papaya; miscellaneous plant debris¹. Semi-slugs may be transported long distances when infested plants or plant parts are moved.

Worldwide Distribution: Parmarion martensi is presumably native to continental Southeast Asia¹. It has also been found in Sumatra, Java, Borneo, Japan, Taiwan, Samoa, and American Samoa¹. It was first found in Hawaii on the islands of O’ahu in 1996 and Hawai’i in 2004¹.

Official Control: Parmarion martensi is not known to be under official control in any other states or nations².

California Distribution: Parmarion martensi has never been found in the environment of California.

California Interceptions: Since March 2009 Parmarion martensi has been intercepted by CDFA’s high risk programs and dog teams 37 times on nursery stock and plant parts imported from Hawaii.

The risk Parmarion martensi would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Parmarion martensi is a polyphagous semi-slug and is likely able to establish anywhere suitable moisture is available in California. It 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: Parmarion martensi is polyphagous on a wide variety of living and decaying 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: Parmarion martensi produces large numbers egg masses¹ and may be transported long distances when infested nursery stock is moved. It 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: Parmarion martensi is an efficient vector of the parasitic nematode that causes rat lungworm disease in humans¹. The semi-slug often feeds on green plants such as lettuce, contaminating the produce with nematodes that can be present in tiny immature semi-slugs or slime. This could have significant impacts on California’s salad industry. Although the semi-slug is not known to be on any quarantine list, its presence in the state may affect markets for California produce if any of it were found to be contaminated with rat lungworm disease. This may lower crop yields if produce were unmarketable and increase crop production costs as growers ensure that fields are free from Parmarion martensi. The semi-slug receives a High (3) in this category.

Evaluate the economic impact of the pest to California using the criteria below. Score: A, B, C, E

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: High (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: Parmarion martensi is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes. It is not expected to directly affect threatened or endangered species or disrupt critical habitats. The semi-slug is likely to trigger additional treatment programs in the nursery industry, by growers, and by residents who find contaminated produce unacceptable. As an efficient vector of the nematode that causes rat lungworm disease, Parmarion martensi has the potential to significantly impact home/urban gardening by sickening residents. The semi-slug receives a High (3) in this category.

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

Environmental Impact: D,E

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

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

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

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

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

Score the pest for Environmental Impact. Score: High (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 Parmarion martensi: 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: Parmarion martensi has never been found in the environment of California and receives a Not established (0) in this category.

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

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

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

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

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

Final Score:

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

Uncertainty:

There have been no recent surveys for semi-slugs in California. It is possible that some of them could have eluded inspections and made it into the state.

Conclusion and Rating Justification:

Parmarion martensi has never been found in California and is likely to have significant economic and environmental impacts if it were to establish here. An “A” rating is justified.

References:

¹ Hollingsworth, R.G., R. Kaneta, J.J. Sullivan, H.S. Bishop, Y. Qvarnstrom, A.J. da Silva, and D.G. Robinson. 2007. Distribution of Parmarion cf. martensi (Pulmonata: Helicarionidae); a new Semi-Slug Pest on Hawai’i island, and its potential as a Vector for Human Angiostrongyliasis. Pacific Science 61(4): 457-467.

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