Insecticidal Soaps for Garden Pest Control | Home & Garden ...
Dry dish detergent and all clothes-washing detergents are far too harsh to use on plants because of all the additives in them. Some soaps and detergents are poor insecticides, and other additives in these products may be phytotoxic (i.e., they may damage the plant). Some plants are sensitive to soap sprays and may be seriously injured by them.