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.”