Diatomaceous earth for crawling insects

Food-grade diatomaceous earth (DE) is a natural powder made from fossilized diatom shells that kills crawling insects (slugs, snails, earwigs, cutworms, ants, and flea beetles) through mechanical action: the microscopic sharp edges lacerate insect exoskeletons, causing dehydration within 24-48 hours. Apply a 2-inch wide ring of DE around plant bases or along bed edges. Dust lightly onto foliage where insects are feeding. Use only food-grade DE (brands: Harris, Safer Brand, Earthborn Elements), never pool-grade DE which contains crystalline silica harmful to lungs. Important limitations: DE becomes ineffective when wet, so it must be reapplied after every rain or overhead watering. This makes it impractical in wet climates or with sprinkler irrigation, but it works well in dry climates or under row covers. Wear a dust mask during application as fine particles can irritate lungs. DE is non-selective and will harm beneficial insects (ground beetles, earthworms) in the application area. Use targeted application around specific vulnerable plants rather than broadcasting across entire beds.