Tritrophic interaction of Helicoverpa armigera (Hubner) in major pulses ecosystem

The seasonal incidence of Helicoverpa armigera (Hubner) and its parasitization in pigeonpea and chickpea under rainfed cropping system of Akola (MS) were assessed during 2004–05 and 2005–06. In pigeonpea ecosystem, early instar H. arrnigera larvae were parasitized by Eriborus argenteopilosus (Cameron) to the extent of 23.5 per cent. Bracon sp. and Campoletis chlorideae (Uchida) had achieved parasitization to the extent of 14.3 and 10.2 per cent, respectively. Tachinid fly could parastize 9.4 per cent late instar larvae and 33.3 per cent H. armigera pupae. Under chickpea ecosystem, E. argenteopilosus parasitized H. armigera larvae up to 16.1 per cent and C. chlorideae registered parasitization up to 14.3 percent, whereas, Tachinid fly could inflict parasitization to the tune of 10.0 and 33.3 per cent in late larval and pupal stages, respectively. Neither larval incidence of H. armigera nor the parasitization by natural enemies were found to have consistent significant relationship with the weather parameters. Present study revealed that the H. armigera incidence was more closely associated with host phenology rather than the weather parameters and the parasitization showed density dependent relationship.