Homemade Formula

• According to Al Ferrer, residential horticulturist at Seminole County Extension, to make your own insecticidal soap spray, "mix 2 tablespoons of vegetable oil, 2 tablespoons of liquid dish soap to one gallon of water and spray liberally on affected plants." The University of Colorado extension recommends experimenting with increasing dilution rates until the least possible amount of soap is used that is still effective.
  
  

Application

• Spray the tops and undersides of orange tree leaves with insecticidal soap to coat all pests on the tree. Apply the spray again in five to seven days to kill any hatching pests. Avoid spraying beneficial insects such as lady beetles, green lacewings and pollinating bees.
  
  

Risks

• Although considered a mild insecticide and approved for organic use on orange trees, insecticidal soaps can damage trees when applied incorrectly. Ferrer cautions, "dish washing liquids and laundry detergents are designed to dissolve grease and for this reason, they may cause plant injury by dissolving the waxy cuticle that covers the leaf surfaces." He recommends rinsing dried soap from plant surfaces shortly after application. In temperatures higher than 90 degrees, insecticidal soaps can cause phytotoxicity, sensitivity to light, in orange trees.
  
  

Garlic and Chili

• Some gardeners advocate the addition of garlic oil and chili pepper flakes to insecticidal soap to deter larger pests, such as crickets and caterpillars and even mammals, such as rabbits, deer and squirrels. These products may also deter beneficial insects. Steep a few crushed garlic cloves and a few tablespoons of chili pepper flakes in diluted insecticidal soap overnight before application.