The most commonly-sold predatory and parasitic insects include ladybugs and the tiny, nonstinging Trichogramma wasp. Because predatory and parasitic insects attack specific prey, know what pests are present before buying a particular batch of beneficial insects. Avoid using insecticides where beneficials have been released. Once beneficial insects have eaten their prey, they will abandon a site in search of more food. The shards abrade soft-bodied insects, causing them to lose fluids and literally dry up.
Diatomaceous earth works best on dry days because humid weather helps damaged insects retain fluids.
Insects controlled by diatomaceous earth may take up to 12 hours to die. Prolonged exposure to diatomaceous earth will irritate lungs and other tissues of people or pets. Because it also kills honeybees, avoid applying the product to crops in flower. Insecticidal Soap . This liquid contains fatty acids derived from plants or animals.