Exploitation of Biocontrol Potential in the Management of Insect Pests of Pulse Crops

Abstract

Advancement in the field of biological control of pests of pulses especially against the pod borer, Helicoverpa armigera has been considerable in the recent past. Of the 112 natural enemies reported, 83 are parasitoids and rest are predators in various crop environments. Egg parasitoid, Trichogramma spp. is claimed to have a little potential on pigeonpea and chickpea ecosystem. Larval parasitism by dipterans and hymenopterans is considerable. Exotic dipteran parasitoid, Eucelotoria brayani is a potential one but, its establishment in the field has not met with success. Relatively less is known about the potentiality of predators in pulses. Release of Chrysoperla carnea, a general predator, has been found to be cost ineffective. Among predatory birds, black drongo, plays a commendable role in pigeonpea ecosystems in Gulbarga, Karnataka. Blue jays, rosy pastor, green bee eater and variety of small omnivorous birds are supplementary species. Errecting bird perches, either inanimate or animate provide the birds a suitable site for landing and searching the prey caterpillars. HaNPV has been the most potential microbial pesticide inflicting upto 90 per cent mortality in the field. However, variation exist in dose recommendation from 250 to 500 LE per ha. Efficacy of NPV is enhanced with addition of UV protectants and phagostimulants. Microbial insecticides are recommended and at reduced dosage in combination with insecticide is reported to be effective. Bacterial pesticide, Bacillus thuringiensis has given mixed results, but high cost seems to be the prohibitive factor. Intercropping pigeonpea with groundnut, sorghum, setaria, maize, etc. encourage the build up of natural enemies. Intercrop termination should be earlier to flowering in pigeonpea to enable transfer of bioagents. Recent findings reveal that conservation of natural enemies is possible by providing a continuous cropping environment especially in short duration pigeonpea.