How to Use Diatomaceas Earth As an Insecticide

J. Lang Wood

Many people are looking for new ways to get rid of insecticides without using toxic pesticides that endanger children and pets and cause runoff that pollutes lakes and streams. Diatomaceous earth is a substance composed of fossilized shells of tiny marine creatures called diatoms.

These remains, which are made of silica sand, are mined for use in agriculture and manufacturing. It is a light, fine powder that is safe and effective when used as an insecticide. Diatomaceous earth works by drying out the protective cover on insects, causing them to desiccate.

  1. Purchase diatomaceous earth from your local nursery or garden supply. It can also be acquired from the large chain hardware stores or farm supply stores, or from a number of organic lawn and pest product supply companies online. Do not use the diatomaceous earth used for pool filters--it is processed with chemicals. Use "food grade" diatomaceous earth for insecticide purposes.

  2. Use gloves and a dust mask when working with diatomaceous earth because, though safe, it can be an irritant when in contact with skin or when inhaled into the lungs.

  3. Apply the diatomaceous earth by dusting on the area. Dust on plants after they are wet from a recent rain to kill destructive insects. Sprinkle over your lawn to control grubs, cinch bugs and ants.

  4. Use diatomaceous earth as a spray. Dissolve 1 to 4 tablespoons in a gallon of water and add a teaspoon of dishwashing soap to make it stick. You can use this in a sprayer to cover high portions of trees and to protect fruit trees. A thicker paste of diatomaceous earth can be used to paint a tree wound to prevent borers. Spraying a solution of diatomaceous earth is a good way to cover a large area like a whole lawn. Remember to regularly shake up the solution to keep the diatomaceous earth suspended in the water or it may clog your sprayer. The diatomaceous earth will begin to work when it has dried.

  5. Reapply after heavy rains. Diatomaceous earth must be dry to be effective.

  6. Use diatomaceous earth as a safe indoor insecticide when use in small amounts. Dust around areas where ants, roaches and silverfish enter your home, around pipes, window frames, doorways, under sinks, into crevices, and behind refrigerators. Dust around the feet of the bed so bedbugs are sure to walk across it and pick it up on their bodies. Sprinkle lightly in attics and basements to prevent termites. Use your hands to dust a handful of diatomaceous earth onto pets to kill mites and fleas. Sprinkle around pets’ sleeping areas. Do not apply heavily. Diatomaceous earth can irritate the lungs when airborne but is safe when settled.

  7. Warning

    Do not use on flowering plants. Diatomaceous earth also kills beneficial insects like pollinators.