Foraging for escargots

I grow many of my own vegetables, but find it harder to get protein. I have corresponded with someone in Washington State who raises escargots, and he mentioned Cornu aspersum was edible, easy to raise, AND invasive. I’ve noticed that there seem to be more snails than slugs as our climate changes.

I would love to volunteer at UW Botanic Gardens and help reduce the snail population. I was on a recent walk and was told that some of the dedicated gardeners come at night with flashlights to find snails, and I would be happy to assist.

Our manager of horticulture says that slug/snail baits are occasionally used as control methods, but there is no such practice as gardeners going out after hours with flashlights seeking slugs and snails in the Arboretum. Your observation about the increasing snail population, and the role of climate change seems to be substantiated. Here is an excerpt from an article in the Everett Herald, which quotes local malacologist David George Gordon: “‘Snails can endure droughts better than slugs because they can pull back into their shells,’ Gordon said. The general warming of the climate, with milder winters, also means there are fewer mass killings during cold snaps.”

The concern when foraging for anything, including invasive snails, is that what you harvest may contain toxic substances. If you want to collect snails, you can try to gather them only from your own garden or a garden you know does not use metaldehyde or iron phosphate-based bait, but even then, they may have been in a landscape nearby and consumed who knows what, including slug bait and poisonous plants.

The USDA APHIS (Animal and Plant Health Inspection Service) has guidelines about quarantine of Cornu aspersum and other non-native mollusk species. This includes not breeding them, and not using them in classrooms or nature facilities. Those who want to cultivate escargots have a different perspective. Perhaps Ric Brewer, the article’s author, is the Washington snail farmer you mention. He doesn’t address concerns about snails in an urban setting, and what they may have consumed beyond the borders of one person’s small city garden, which is not a closed system.

A safer and more ecologically sound way to introduce protein sources into your garden would be to grow sunflowers for their seeds, and if you have space, a couple of nut-bearing trees.

Food safety, Invasive species, Snails

About diatomaceous earth and slugs

Someone suggested that I could use diatomaceous earth to get rid of slugs in the garden. Is this a good idea? Any drawbacks I should consider?

First, here is a definition of what diatomaceous earth is, from the National Pesticide Information Center: “Diatomaceous earth is made from the remains of diatoms, which are tiny organisms that lived in rivers, streams, lakes and oceans. Diatom skeletons are made up of silicon dioxide, a combination of silica and oxygen. Silica is very common in nature and it makes up 26% of the earth’s crust. Diatomaceous earth is very abrasive to an insect’s exoskeleton, causing them to dry out and die.”

Slugs are not killed by diatomaceous earth, though it may slow them down. It is mainly used to control insects with hard exoskeletons. According to the book Mason Bee Revolution (Dave Hunter and Jill Lightner, Skipstone Press, 2016), the abrasive dust can damage the bodies of butterflies, spiders, and some bees by causing severe dehydration; it can also kill beneficial hard-shelled bugs. It is considered a relatively low toxicity method of pest control, usually sold as a dust. However, it is not entirely risk-free: wearing a respirator is recommended. Prolonged exposure can cause serious problems like silicosis).

Using submerged saucers of beer will take care of slugs without adverse consequences for non-target species. A potential alternative slug and snail control method that has yet to be researched thoroughly is using wool as a compost or in pelletized form. Excerpt: “Wool may also be included in mulch or mats where it has been shown to reduce predation by slugs and snails, eliminate weed growth, and reduce soil temperature variation.”

Pesticide safety measures, Pests, Slugs, Snails

snail and slug control

I have a big snail population in my yard. I don’t use pesticides and I want to avoid Sluggo or other iron phosphate type baits.

I have read online that decollate snails (Rumina decollata) eat brown garden snails (Helix aspersa). I’m thinking about ordering some of these as they say the decollate snails don’t eat your plants. Also I’ve read that garter snakes will eat the slugs and snails.

Decollate snails may not be imported into the Pacific Northwest. See this information from Oregon State University on nursery pests, excerpted here:
“Decollate snails, Rumina decollata, have been reared and released as biological control agents to control brown garden and other snails. They are native to the Mediterranean and have been in the US since the 1820s and in southern California since the 1950s. They are commercially available and have been used rather commonly in citrus orchards in California. They can harm native snails and are also plant feeders themselves. Decollate snails are prohibited from shipment to the Pacific Northwest but have managed to slip in at times.”

Oregon also lists Rumina decollata on its 2003 Invasive Species Report Card, and states that it is polyphagous, eating both plants and other snails:
“decollate snail, Rumina decollata (a polyphagous species that consumes both plant material and other snails, promoted as a biological control agent in areas heavily infested with European brown garden snail in California, reported for sale in a Eugene garden center in 2003)”

The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) also states that decollate snails cannot be permitted across state lines:
“Decollate snails (Rumina decollata) and aquatic snails in the family Ampullaridae (e.g., Pomacea canaliculata, channeled apple snail), with one exception, may not be imported or moved interstate except for research purposes into an APHIS inspected containment facility.”

I’m not sure I’d recommend importing garter snakes, though there may be natives already in your garden or surrounding areas. See the Washington Department of Fish and Wildlife’s information about our native species, which includes tips for attracting snakes.

There are much easier methods than the above for controlling destructive snails. The same traps that work for slugs–beer in saucers, upturned melon rinds, or copper barriers around plants–should help. A vigilant eye will catch lots of them, too, and they can be squished if you aren’t squeamish. More information from University of California, Davis Integrated Pest Management is here.

I understand your reluctance to use iron phosphate products like Sluggo. Although it is certified as acceptable for organic use by the Organic Materials Review Institute (OMRI), information published on the website of Oregon State University in May 2013 quotes recent research suggesting that even “less toxic” iron phosphate slug bait can cause iron toxicosis, and should be kept away from animals and children. Here is a fact sheet from the National Pesticide Information Center which explains the risks. Stormwater runoff may also be a concern, although one typically doesn’t use much of the stuff at a time. You might borrow a duck or two to come in and do some serious snail-eating!

on the use of iron phosphate based slug baits

Is there any scientific reason to not use the iron phosphate based slug baits (Sluggo etc.) near bodies of water (streams, ponds, lakes)? I did some preliminary (not exhaustive) Google research and did not find anything to suggest they cause increased algae growth. Please let me know what you can find on this subject. Are other
water-borne organisms harmed?

The Material Safety Data Sheet for Sluggo indicates that one should avoid
disposal of this product near bodies of water (see Section 13), though
there is not definitive information in Section 12 on the ecological
impacts of the product on algae and other life forms. Here is a link to the PDF document.

See also Grow Smart from King County Hazardous Waste Management on dealing with slugs in gardens.

It does not list Sluggo, Escar-go, or any of the other iron phosphate
products as water pollution hazards, but the MSDS sheet makes me think
there is a potential problem with dumping large quantities. It seems not
enough information is out there, perhaps because the research has not
been done. Here is the page from the Pesticide Action Network database, where you can see that iron phosphate’s eco-toxicity has not been
established.

Here is what the Environmental Protection Agency has to say about iron
phosphate slug baits:

Ecological Effects Hazard Assessment

“A number of ecological effects toxicology data requirements were waived
based on the known lack of toxicity of iron phosphate to birds, fish and
non-target insects, its low solubility in water, conversion to less
soluble form in the environment (soil), and its use pattern (soil
application). An acute oral toxicity study in Bobwhite quail (NOEL & LD50
greater than 2000 mg/kg) indicated that iron phosphate was practically
nontoxic to avian species. Based on these factors, the data requirements
for the toxicity studies in Mallard duck, rainbow trout, freshwater
invertebrates, and non-target insect/honeybees are waived. It is likely
that there will be exposure to ground-feeding non-target insects and
earthworms. Submitted studies involving ground beetles, rove beetles and
earthworms demonstrated that the product will not affect these organisms
at up to two times the maximum application rate.

Environmental Fate and Ground Water Data

Exposure assessments on this type of product (biochemical pesticide) are
not performed unless human health or ecological effects issues arise in
the toxicity studies for either of these disciplines. Since no endpoints
of concern were identified, there is no requirement for environmental
fate data.

Ecological Exposure and Risk Characterization

Exposure to daphnids and other aquatic invertebrates would not occur
based on current label use directions. Exposure to honeybees is also not
expected to occur, due to the composition and particle size of the
end-use product and its use pattern (soil application). Non-target
insects, such as ground beetles and earthworms, could encounter the
end-use product; however, in tests of rove beetles, ground beetles and
earthworms, no effects were observed at up to twice the maximum
application rate. Thus, the acute risk to aquatic invertebrates,
non-target insects, and earthworms is considered minimal to nonexistent.”

United Nations Environment Programme has information on the impact of Phosphorus on aquatic life, a process called eutrophication. However, the iron phosphate in Sluggo and similar products binds with Phosphorus, which may mitigate the effects in water.

Garden Tip #72

What unites gardeners from all walks of life? A passionate loathing of slugs and snails. Perhaps if we understood these little slimy mollusks better – their lifecycle, their tastes – we\’d learn to appreciate them for the successful creatures they are. Or at least we could learn how to drive them out of our gardens with the latest science has to offer.
The BBC’s Science and Nature web site once had an in-depth article on snails and slugs that made fascinating reading. https://www.bbc.co.uk/nature/animals/features/291feature1.shtml

This interview with malacologist Mary Seddon may be interesting: https://www.bbc.co.uk/programmes/b01ntj9z

Slugs have memory and will return another night to finish off tasty seedlings until they are all gone.
A few plants slugs find distasteful: foxgloves, many species in the daisy family, Lavateras, hollyhocks, azaleas, Euphorbia, hardy Geraniums.

A long list of “Slug Resistant Plants” is given in a Seattle Times article by local writer Valerie Easton.