Parasitoids are small to tiny animals that search for hosts that are themselves small or tiny animals in a very complex environment. Insect parasitoids have been shown to be effective in suppressing a limited number of pest species both in bulk grain storages and in food-processing facilities and warehouses.
One of the more effective parasitoids is Theocolax elegans, a small pteromalid wasp (1–2 mm) that attacks primary grain pests, whose immature stages develop inside the grain kernels, including the weevils, Sitophilus spp., lesser grain borer, Rhyzopertha dominica (F.), drugstore beetle, Stegobium paniceum (L.), cowpea weevil, Callosobruchus spp., and Angoumois grain moth, Sitotroga cerealella.
The use of insect parasitoids and predators to control stored product insect pests has many advantages over traditional chemical controls. These natural enemies leave no harmful chemical residues.
When released in a storage facility, they continue to reproduce as long as hosts are available and environmental conditions are suitable. Unlike chemicals that need to be applied to a wide area, natural enemies can be released at a single location. They will actively spread, find, and attack pests located deep inside crevices or within a grain mass.
Grain stored pests: Parasitoids
