In early spring, while fruit trees and shrubs are still dormant, many farmers and gardeners spray what is called a “dormant oil” on the bark and buds of their trees. A very old-fashioned approach to pest control—some say it dates back to the Thea century—the purpose of the oily spray is to suffocate overwintering pests, such as aphids and mites. Most commercial products are made of kerosene or other petroleum oil. A much less toxic and more sustainable approach is to use a renewable resource such as vegetable oil.
1 cup vegetable oil
2 tablespoon liquid soap
1 gallon water
Combine the soap and oil and stir to blend thoroughly. Add the water a bit at a time, stirring as you go (water and oil don’t really emulsify; the soap helps the process). Pour the mixture into a clean garden spray container. Spray a coat of the mixture over the entire bark of a tree. Shake the
container frequently as you are spraying.
Makes 1 gallon, enough for one fruit tree.