Role of Natural Enemies in Pest Management

Using natural enemies for managing pests is an ecological approach for pest management which helps in preventing insects from reaching the damaging stage.

The basic relationship among organisms is food. Hence, all organisms are related through a food web. In the case of insects, there are predators and parasites that act as natural enemies. Predators could be insects, birds etc. while parasites (parasitoids) are mostly insects belonging to wasp and fly families. The basic difference between a predator and parasitoid is – for predators it is a part of a single meal whereas for a parasitoid part of its life (egg or larva or both) is spent on the host. Various predators are – among insects: carabid beetles or ground beetles, Ladybird beetles, praying mantis, dragonfly etc.; among birds: owls, bats, drango, etc. Among parasitoid insects, egg parasitoids like Trichogramma wasp; larval parasitoids like Bracon wasp, Apanteles wasp; pupal parasitoids like Tetrastichus wasp, Trichospilus wasp etc. are present naturally in the crop ecosystem based on the crop and the crop pest. Spraying chemical pesticides will drive away these beneficial insects. Some of them are available in the markets for releasing in the field.

a. Braconid wasp and Cotesia glomerata (a White Butterfly parasite)

b. Apechthis ontario (Ichneumonid parasitoid wasp)