Old Cobblers Farm™ Wicked Repellent
Diatomaceous Earth Insect Killer

Diatomaceous earth is effective against virtually any crawling insect with an exoskeleton. This includes ants, fleas, ticks, bed bugs, cockroaches, earwigs, silverfish, crickets, centipedes, millipedes, pill bugs, mites, aphids, and most beetle species including Japanese beetles, flea beetles, and Colorado potato beetles. It also deters slugs and snails as a barrier (though it does not kill them). DE is NOT effective against caterpillars (their mucus layer protects them) or flying insects that do not come into contact with treated surfaces. Earthworms are also unaffected due to their protective mucus coating.

Yes — food-grade diatomaceous earth is non-toxic to all mammals including dogs, cats, and livestock. It is commonly used as an anti-caking agent in animal feeds and can be applied directly onto pets to kill fleas, ticks, and mites. Work the dust gently into your pet's fur, avoiding the eyes, nose, and mouth as it can cause mechanical irritation to mucous membranes. For flea control, treat the pet AND their bedding, carpets, and resting areas simultaneously to break the flea life cycle.

No. Diatomaceous earth is ONLY effective as a dry powder. When wet, the microscopic diatom shells cannot abrade insect exoskeletons and the silica cannot absorb moisture from insect bodies. If you apply DE mixed with water (for foliar coverage), it must dry completely on the surface before it becomes active — typically 1-2 hours. After rain, heavy dew, or irrigation, all outdoor DE must be reapplied. Indoor applications in dry locations (wall voids, cracks, behind appliances) remain effective indefinitely.

Yes — DE is non-selective and will harm any insect with an exoskeleton that contacts it, including bees, ladybugs, lacewings, and parasitic wasps. To protect pollinators: never dust open flower blooms, apply in early morning or evening when pollinators are inactive, target soil surfaces and plant stems rather than flower heads, and mow lawns before application to remove blooming clover. DE settles into the soil surface within 24-48 hours, significantly reducing risk to flying beneficial insects after the initial application.

Outdoors: reapply after every rain event, heavy dew, or irrigation cycle — DE is useless when wet. In dry conditions, outdoor applications can remain effective for several weeks. Indoors: applications in dry areas like wall voids, behind baseboards, and under appliances last indefinitely and do not need reapplication. For active infestations of life-cycle pests (fleas, bed bugs), reapply every 7-10 days for at least 3 cycles to kill newly hatched insects that emerge from eggs.

This is critical: ONLY use food-grade DE for pest control. Food-grade DE contains amorphous (non-crystalline) silica and is safe for humans, pets, and food contact. Pool-grade (filter-grade) DE is heat-treated (calcined), which converts the silica to crystalline form — crystalline silica is a known carcinogen and extremely dangerous to inhale. Pool-grade DE should NEVER be used for pest control, in gardens, around pets, or anywhere near living spaces. Always verify the label says 'food grade' before purchasing.

Yes. Food-grade DE is OMRI Listed for organic crop production and can be applied directly on edible plants including tomatoes, peppers, squash, herbs, leafy greens, and fruit. There is no pre-harvest interval — you can harvest and eat the same day you apply. The FDA approves food-grade DE as a direct food additive at up to 2% concentration. Simply wash produce normally before eating to remove visible dust residue. Apply DE on soil around plant bases and on leaf surfaces (especially undersides) where pest insects feed.