Diatomaceous Earth

Diatomaceous earth is a naturally occurring, soft, siliceous sedimentary rock. It is harvested from sediments at the bottom of oceans, lakes, and rivers around the globe. It comes from diatoms – a type of single-celled algae with microscopic, geometric shells made of silicon dioxide. Over millennia, diatoms accumulate in aquatic sediments as fossils that can be harvested and dried into a fine white dust.

Diatomaceous earth is very cost effective but has some limitations:

  • DE is not target specific. 
  • There is wide variation in insect susceptibility depending on soil moisture.
  • Can not be used with beneficial predator mites in soil.
  • Dramatically looses efficacy when soil becomes wet.
  • Undesirable residue makes foliar applications impractical.


Target Pests

  • Fungus gnats, various insects

Mode of Action: Diatomaceous earth (DE) kills insects by dessication - meaning it draws the moisture out of the insects, dehydrating them to death.

Application Tips: While DE is inert and harmless to skin contact, there is an important health issue regarding respiratory exposure to crystalline silica dusts. Excessive inhalation may result in silicosis or other respiratory diseases. Exposure to excessive amounts of air-borne dusts, even inert dusts, is not advisable and the use of a disposable dust mask and goggles is recommended when handling the product.

DE becomes much less effective when wet. This poses problems to soil

Impact on Beneficial Insects: Moderate to High

Selected References: