Rake up and destroy fallen, diseased leaves and twigs. Make use of biodiversity by planting a variety of species in your landscapes. Biological control makes use of beneficial organisms such as predators, parasites and disease-causing bacteria, viruses, fungi or nematodes to control pests. Ladybird beetles, which feed on soft-bodied pests such as aphids, help keep those pests under control. Caterpillars and many other pests can be kept at bay by parasites such as small wasps and flies.
Bacteria also help control caterpillars and several other pests.
This is sometimes separately called microbial control. Genetic control means using plants that have been selected or genetically manipulated to become resistant or less susceptible to pests. Mechanical or physical control methods involve using barriers or traps to prevent or reduce pest problems. Use traps with baits to reduce or monitor pests such as the gypsy moth and dogwood borer. A more common physical control is the window screening we use to keep pests out of our homes.