Today, pesticidal soaps are making a comeback. Soaps are virtually non-toxic to the user and they degrade rapidly in the soil.
Soaps can cause eye irritation, so wear goggles and follow the safety precautions on the label.
In order to kill a pest with soap, the material must come in contact with the pest's body. Caterpillars, beetles, wasps, flies, and grasshoppers are less affected by soaps. Slow-moving insects are more susceptible than highly mobile ones that can fly away from the spray. Because soaps can harm beneficial insects, check your plants before you treat. If you find a number of beneficials feeding on the target pest, wait for several days.