Diatomaceous Earth (DE) or Diatom Flour is not only an excellent insecticide but is often used as a wormer for livestock as well. With its microscopic razor-sharp prisms, it physically kills and deters without the use of harmful poisons. DE can be dusted or sprayed as a control for most leaf-eating insects and used in a band to deter slugs and snails. Mix one cup per gallon of water and pour through sack clothe or fine screen before spraying. DE is a very indiscriminate pesticide and can harm beneficial insects. It should not be used where there is a danger of harming bees or other beneficial insects.
DE is a natural product mined in the American West. It was formed from trillions of microscopic one-celled algae called diatoms that wove tiny shells for themselves out of the silica they extracted from water. As the diatoms died, these shells settled in deposits at the bottom of ancient lakes and lagoons. When the lakes dried up and seas receded the deposits were fossilized and compressed into a soft, chalky rock called diatomaceous earth. After it is quarried, milled, finely ground, and passed through a centrifuge, it looks and feels like flour and can be fed to animals, not only to control worms and other parasites, but also as a feed supplement containing trace minerals.
It is an effective animal wormer because worms and soft-bodied insects are unable to withstand the killing action of diatomaceous earth. Death occurs about 12 hours after insects venture into the product. Their skins are pierced by the sharp edges of the diatom’s shell causing fatal dehydration.
DE can be fed to livestock as a wormer. For larger animals (cows, horses, mature pigs, elephants, etc.), mix with feed at 2 percent by weight. For smaller animals (sheep, small pigs, dingoes, etc.), mix 1 percent with feed. It can also be fed with salt at 20 percent.
DE can also be used to protect stored grains. Use one cup per 50 pounds of grain or one pound per 300 pounds of grain. 50 pounds of DE will protect seven tons of grain for an indefinite period of time.
3% DE in potting mixes protects against fungus gnat and shorefly larvae.
Not all DE is the same. DE made for swimming pool filters is inappropriate for insect and worm control or for the protection of grains. Of the 600 deposites of DE west of the Mississippi River, only four have material with the appropriate characteristics for insect and worm control. Only feed-grade DE should be fed to livestock. Non-feed-grade material may contain contaminants that could harm livestock. Diatomaceous Earth contains less than one-percent quartz crystalline silica.
For more information, download the product label pdf.