Parasitization of Helicoverpa armigera (Hubner) on Pigeonpea

The parasitization of Helicoverpa arinigera (Hubner) larvae and pupae was studied during 2004-05 and 2005-06 from field collected life stages on pigeonpea. The ichneumonid, Eriborus argenteopilosus was found to be the most effective and active parasitoid of early instar larvae from 45^th Meteorological week (MW) till 51^st MW and recorded the highest parasitization in 46^th MW (25.00 per cent). The other ichneumonid, Campletis chlorideae was observed to be active in December (16.67 per cent). Parasitism by a Braconid, Bracon sp., noticed from 45^th to 47^th MW and 50^th MW, was up to an extent of 7.89 per cent. On pigeonpea, these parasitoids contributed to approximately two-third of the total mortality of early instar H. armigera larvae. Tachinid parasitoids were found to be associated with the late larval instar and pupae. The parasitization of late larval instars was noticed from 47^th MW to 52^nd MW and the population reduction was estimated to be 17.86 per cent, which was highest in 48^th MW. Similarly, HaNPV disease infection also played an important role in population suppression of early and late instar larvae to an extent of 7.69 and 3.57 per cent, respectively. Pupal mortality by a tachinid was noticed from 46^th MW to 52^nd MW in the range of 8.33 to 26.32 per cent.