Information Requests Monitoring System

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Request ID: 154
Request From: Steve Toth
Date Requested: Apr 13, 2006
Request: Please note the following request for information regarding metaldehyde use for snail and slug control in agriculture, home and gardens, and public lands. Forward this request (see attachment) to the experts in your respective states/territories and submit any responses to the Southern Region Information Requests Monitoring System by Friday, April 28, 2006. Thanks. Steve Toth ----------------------------------------------- Attached are some questions regarding the use of metaldehyde for snail and slug control in agriculture, home and gardens, and public lands. Please forward these on to the people in the know. I will also include a brief description of the concerns EPA has with metaldehyde just for your information. It is always helpful to understand why the questions are being asked. Please direct responses directly to the Chemical Review Manager, Jill Bloom ( Bloom.jill@epa.gov ), and please cc any correspondence to me as well. Deadline: I am late getting this out so instead of April 24th which is what EPA asked for how about April 28th. As always, thank you in advance. Jill Bloom, Review Manager US Environmental Protection Agency Office of Pesticide Programs Special Review and Reregistration Division 703-308-8019 fax: 703-308-8041 Wilfred Burr USDA/OPMP 1400 Independence Ave. SW Washington, DC 20250-0315 202-720-8647 Wilfred Burr USDA/OPMP 1400 Independence Ave. SW Washington, DC 20250-0315 202-720-8647

Responses
Responder: Darrell Hensley
State: KY
Date Requested: Apr 17, 2006
Response: QUESTIONS FOR USDA DATA-GATHERING ON USE/USAGE OF METALDEHYDE AND OTHER SLUG/SNAIL CONTROLS How serious a problem are snails and slugs in your Region for the following situations: In agriculture (by crop, if possible please), specifically, are snails and slugs economic pests? Slugs are common pests in the early spring and can serious damage field corn, tobacco, strawberries, cucurbit crops, and some others. But there is often little yield loss associated with attack on field crops. However, with horticultural crops there can be significant loss in some years/situations. Home/garden? Yes, they are a problem with home gardens both in terms of plant damage, nuisance, and mess (slimy trails). Pubic lands (particularly parks)? Don't know How is metaldehyde (ex. Slugit, Deadline, Corry’s Slug and Snail Death) used your in the Region? Not used much do to the expense and the need to reapply. Slugs are common during rainy periods, but the rain also ruins the slug baits. The high cost of the treatments also limits their use. Rates? How often is it used per season or crop cycle? What are the intervals between applications? How is it applied? What are the uses and usage of metaldehyde alternatives in the Region? Examples may include: Methiocarb (Mesurol) Iron phosphate (ex. Sluggo, Escar-go, Schultz Garden Safe Slug and Snail Bait, Worry Free Slug and Snail) Coconut oil soap (Concern SlugStop) Copper sulfate slurry or Bordeaux mixture Metallic copper strips or foil (ex. Snail-Barr) Decollate snails How efficacious are the chemical controls for snails and slugs? Only partially effective. How effective are nonchemical controls in reducing snail/slug damage? Homeowners have used the beer traps with some inconsistent results. What cultural controls are used if any and how effective are they in the agricultural settings? Are there any use sites for which growers/users view metaldehyde as critical to production or aesthetics? If so, why? Yes, u-pick strawberries. If applicable, please provide research contacts in your Region who have looked into relative efficacy of slug/snail pesticides (or other aspects of slug/snail control). RISK SUMMARY FOR METALDEHYDE Prepared by Jill Bloom, 4/6/06 No conventional dietary exposures result in risks of concern. No residential handler or post-application risks of concern have been identified. No worker risks of concern have been identified. Domestic animals (usually dogs) can be attracted to and ingest metaldehyde granules; poisoning typically results in death. Formulators now incorporate a bittering agent in home/garden products, but empirical evidence of its effectiveness in preventing domestic animal incidents is lacking and poisoning data are not conclusive. Ecological risks of concern have been identified. Risks to wildlife are calculated as Risk Quotients (RQs), and compared to Levels of Concern (LOCs) for acute, chronic, and endangered species risks. RQs above these LOCs represent risks of concern. For metaldehyde, there are no toxicity data on which to estimate: chronic risks to freshwater invertebrates acute and chronic risks to estuarine/marine fish, acute and chronic risks to estuarine/marine invertebrates, risks to aquatic plants (for plants in general, risk is expected to be low), risk to freshwater and estuarine/marine mollusks (because metaldehyde is a mollusicide, these risks are likely to exceed LOCs) Acute risks to freshwater fish do not exceed the LOC. Acute risks to freshwater invertebrates were not estimated as metaldehdye was practically non-toxic in a submitted study on Daphnia. Acute risks to birds exceed levels of concern for one or more food sources, and one or more sizes of bird, in all use sites: RQs range from 0.02-13.3 (compared to the LOCs for acute risk at 0.5 and for acute endangered species risk at 0.1). The highest risks are associated with smaller birds, watercress, grass grown for seed, and ornamentals. Acute risks to mammals exceed levels of concern for one or more food sources, and one or more sizes of mammal, in all use sites: RQs range from 0.03-2.89 (compared to the LOCs for acute risk at 0.5 and for acute endangered species risk at 0.1). As above, the highest risks are associated with smaller animals, watercress, grass grown for seed, and ornamentals. Chronic risks to birds exceed levels of concern for most food sources in watercress: RQs range from >0.5->18.1 (compared to the LOC for chronic risk at 1). Chronic risks to mammals exceed levels of concern for most food sources, and for all sizes of mammal, in watercress: RQs range from 0.06-5.9 (compared to the LOC for chronic risk at 1). Chronic avian and mammalian risks were not assessed for granular applications (other use sites), but are expected to be high.

Responder: Henry Fadamiro
State: AL
Date Requested: Apr 25, 2006
Response: We have had to treat for snails in our greenhouse here in Southern Alabama with bait formulations of this product. Snails will eat moderate amounts of citrus foliage if they get established and go untreated. I'm sure sanitation and watering practices play a role in their control also. It is my understanding that it is a fairly common garden and greenhouse pest in Alabama.

Responder: Ronald Oetting
State: GA
Date Requested: Apr 26, 2006
Response: QUESTIONS FOR USDA DATA-GATHERING ON USE/USAGE OF METALDEHYDE AND OTHER SLUG/SNAIL CONTROLS How serious a problem are snails and slugs in your Region for the following situations: In agriculture (by crop, if possible please), specifically, are snails and slugs economic pests? In the ornamental industry slugs and snails are a serious problem with few alternatives for management. They are a problem in greenhouse production and in outdoor nursery production.. Home/garden? They are definitely a problem in the home landscape and garden. Pubic lands (particularly parks)? How is metaldehyde (ex. Slugit, Deadline, Corry’s Slug and Snail Death) used your in the Region? Rates? The majority of the people use one of the grandular baits. Some use the paste. How often is it used per season or crop cycle? It is used often when slugs and snails are a problem . What are the intervals between applications? I am not sure and it varies a lot from grower to grower and homeowner to homeowner. I would guess that it is applied as often as every few days but definitely at least once a week when the problem is noticeable. How is it applied? Primarily as granules spread in the area of heaviest infestation. Not usually as a general preventative application over the entire area. What are the uses and usage of metaldehyde alternatives in the Region? Examples may include: Methiocarb (Mesurol) Used as a foliar spray on ornamental plants primarily for thrips but some for slugs. Iron phosphate (ex. Sluggo, Escar-go, Schultz Garden Safe Slug and Snail Bait, Worry Free Slug and Snail). I don’t know anyone that uses it and I don’t know if it is even available. Coconut oil soap (Concern SlugStop) I do not know of any use nor availability. Copper sulfate slurry or Bordeaux mixture Used on a very limited scale. Metallic copper strips or foil (ex. Snail-Barr) Not used at all Decollate snails Not used at all. How efficacious are the chemical controls for snails and slugs? Marginal. It required persistence and repeat applications. How effective are nonchemical controls in reducing snail/slug damage? None that I am aware of. What cultural controls are used if any and how effective are they in the agricultural settings? In ornamental production it is hard to keep things dry so the only cultural management is the elimination of sites for them to hide during the day. Are there any use sites for which growers/users view metaldehyde as critical to production or aesthetics? It is critical in all ornamental areas. If so then why? It is the only compound that is readily available and works. If applicable, please provide research contacts in your Region who have looked into relative efficacy of slug/snail pesticides (or other aspects of slug/snail control).

Responder: Mark Mossler
State: VI
Date Requested: Apr 27, 2006
Not Important/Relevant to my state(s)
Response:

Responder: Mark Mossler
State: PR
Date Requested: Apr 27, 2006
Not Important/Relevant to my state(s)
Response:

Responder: Mark Mossler
State: FL
Date Requested: Apr 27, 2006
Not Important/Relevant to my state(s)
Response: Florida has very minor use of metaldehyde since are soils are sandy and moisture does not accumulate historically. There is a small amount documented in avocado production (5% treated) with the bait. The watercress grower we have here does have slug/snail problems, but the bait would not work. They are currently trying to get the flowable formulation (Slugfest) registered for that crop.

Responder: Mark Mossler
State: FL
Date Requested: Apr 27, 2006
Not Important/Relevant to my state(s)
Response: Florida has very minor use of metaldehyde since our soils are sandy and moisture does not accumulate historically. There is a small amount of use documented in avocado production (5% treated) with the bait. The watercress grower we have here (large national producer) does have slug/snail problems, but the bait would not work. They are currently trying to get the flowable formulation (Slugfest) registered for that crop.

Responder: John Van Duyn
State: NC
Date Requested: Apr 28, 2006
Response: Here are some answers to the slug/snail questions relevant to my situation: 1. Slugs are an occasional problem in conservation tillage planted corn and cotton, during periods of cool, damp weather (not uncommon in early spring). 2. Deadline bullets are sometimes recommended in corn and the product is applied at a label specified rate, usually 10 lb/acre. It is usually applied by aircraft. 3. Mesurol is not labeled for cotton or corn. I have no experience with iron phosphate, but if it were adequately effective it may be a possible substitute for metaldehyde in corn. The others listed are also not alternatives for cotton or corn at present. 4. Deadline bullets are reasonably effective but in most cases it is hard to tell because slug problems are often short-lived, disappearing after a few days of sunny weather (did the Deadline kill them or was it the weather?????). 5. As indicated, the usual cultural control recommendation is to wait for some hotter, drier weather (which can usually be accommodated, except in situations of high populations and very small seedlings). 6. In field crops it is hard to tell if the preservation of metaldehyde is critical due to the low frequency of the problem. However, this does not mean that preserving metaldehyde is not important. I believe it should be retained as an insurance factor for the preservation of conservation tillage practices and the many benefits associated with this concept. Conservation tillage corn is, on average, much more affected by seed and seedling pest problems, including slugs,that act in concert to reduce final plant populations. This situation is continuing to evolve. John Van Duyn Extension Entomologist North Carolina State University

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