Safer's Trounce Yard & Garden Insecticide combines pyrethrins and potassium salts of fatty acids to kill insects on contact. The pyrethrins attack the insect's nervous system and potassium salts weaken the insect's protective outer shell. It controls a variety of insects including aphids, whitefly, scale, spider mites and mealybugs. Trounce can be used on fruit trees, landscape trees, ornamentals, flowers, shrubs, and vegetables.