The uses for diatomaceous earth are many, but in the garden diatomaceous earth can be used as an insecticide. Diatomaceous earth works to get rid of insects such as:
Aphids, Thrips, Ants, Mites, Earwigs, Bedbugs, Adult Flea Beetles, Cockroaches, Snails and Slugs
To the insects, the diatomaceous earth is a lethal dust with microscopic sharp edges that cut through the insect’s protective covering, causing them to dry out, thus killing them when they are either dusted with the diatomaceous earth or applied in a wet spray form.
One of the benefits of diatomaceous earth for insect control is that the insects it helps to control have no way to build up a resistance to the diatomaceous earth, like with many of the chemical control insecticides.
How to Apply Diatomaceous Earth In The Garden
Most places where you can purchase diatomaceous earth will have complete directions on the proper application of the product. As with any pesticide, be sure to read the label thoroughly and follow the directions thereon! The directions will include how to properly apply the diatomaceous earth (DE) both in the garden and indoors for the control of many insects as well as forming a barrier of sorts against them.
In the garden diatomaceous earth may be applied as a dust with a dust applicator approved for such use; again it is of the utmost importance to wear a dust mask during application of the diatomaceous earth in this manner and leave the mask on until you have left the dusting area. Keep pets and children clear of the dusting area until the dust has settled.
In my opinion, it is better to apply the product in a wettable form to avoid the airborne dust particles problem, even then wearing a dust mask is a garden smart action to take. When using as a dust application, you will want to cover both the top and underside of all foliage with the dust. If it rains right after the dust application, it will need to be reapplied. A great time to do the dust application is right after a light rain or in the very early morning when the dew is upon the foliage as it helps the dust to stick well to the foliage.
For doing the spray application of diatomaceous earth, the mix ratio is usually one (1) cup of diatomaceous earth per ½ gallon or two (2) cups per gallon of water. Keep the mix tank agitated or stir it often to keep the diatomaceous earth powder well mixed with the water. This mix may also be applied as a paint of sorts to trees and some shrubs.