Diatomaceous Earth (DE) is an effective, non-chemical pest control agent that can be used to manage earwig populations. This fine, naturally occurring powder is the fossilized remains of diatoms, a type of microscopic aquatic algae with silica-based shells. Diatomaceous earth is primarily composed of amorphous silica and works as a mechanical insecticide, offering a highly reliable, non-toxic option for household and garden pest management.
How Diatomaceous Earth Kills Insects
Diatomaceous earth functions as a physical means of pest control. The tiny, sharp fragments of the fossilized diatoms are abrasive to insects that crawl over them. This action causes microscopic damage to the insect’s protective outer layer, known as the exoskeleton.
The exoskeleton of an earwig is coated in a waxy, lipid-based layer that is crucial for retaining internal moisture. Once the DE particles scratch this barrier, the powder begins to absorb the lipids and moisture from the earwig’s body. This process of moisture loss is called desiccation, and it leads to the insect’s dehydration and eventual death.
The physical nature of this mechanism means that insects cannot develop a biological resistance to it, unlike many chemical pesticides. While the product begins working immediately upon contact, it may take up to 48 hours for the earwig to fully succumb to the effects of desiccation. Since earwigs possess a segmented exoskeleton, they are highly susceptible to the physical damage caused by the silica particles.
Applying DE Specifically for Earwig Control
Effective control involves applying the diatomaceous earth as a fine, dry barrier in the areas where the pests hide and travel. Earwigs are nocturnal and seek dark, damp environments during the day, so application should target these hotspots. Key areas include under stones, mulch, flower beds, and along the foundation of a home.
Sprinkle a thin, almost imperceptible layer of the powder around garden beds to create a perimeter that earwigs must cross. Applying a fine layer is more effective than a thick pile, as earwigs will simply walk around excessive mounds. A powder duster can help ensure a light, even spread, which increases the likelihood of contact with the particles.
Indoors, focus on dusting areas like baseboards, window sills, and around cracks or crevices that serve as entry points. Since earwigs are attracted to moisture, applying DE in damp basement corners or under sinks can be particularly effective. Diatomaceous earth loses its effectiveness when it becomes wet because the moisture causes the fine particles to clump together.
Re-application is necessary after rainfall or heavy watering in outdoor areas to maintain the protective barrier. Apply the product in the evening before earwigs become active and when the powder can remain dry for several hours. Consistent re-application ensures the mechanical barrier remains active against the crawling pests.
Safety and Handling Precautions
When selecting diatomaceous earth for pest control, choose a product labeled as Food Grade. This designation means the product contains a low amount of crystalline silica (typically less than 1%) and is largely composed of amorphous silica. The amorphous form is considered safe for use around humans, pets, and plants for insecticidal purposes.
Conversely, Filter Grade or Pool Grade DE has been heat-treated and contains a significantly higher concentration of crystalline silica (sometimes up to 60%). This type of DE is intended only for industrial uses, such as water filtration, and is toxic to inhale, making it unsafe for home pest control. Always confirm the product is uncalcined food grade for home use.
While Food Grade DE is safe, inhaling any fine powder can cause respiratory irritation, so wearing a simple dust mask during application is a precaution. The powder is non-toxic to touch but can cause temporary drying of the skin due to its moisture-absorbing properties. By taking these simple steps, you can safely apply this natural product to manage earwigs in your environment.