Made from the potassium salts of fatty acids, insecticidal soaps cause desiccation and death on direct contact with susceptible insects. The acids disrupt the structure and permeability of their cell membranes. Most effective on soft-bodied insects, including beneficial insects, these soaps have a minimum impact on ladybug larvae and parasitic wasps. Aside from causing mild eye and skin irritation, they have low mammalian toxicity and are biodegradable. Once dry, however, they are no longer effective.