Field Evaluation of Exotic Larval Parasitoid, Allorhogas pyralophagus Marsh Against the Larvae of Scirpophaga excerptalis Walker

Field evaluation of the exotic larval parasitoid, Allorhogas pyralophagus Marsh was carried out under field conditions at the Indian Institute of Sugarcane Research (IISR) farm (Lucknow), Simbhaoli (Gbaziabad) and Majethia Farm (Sardarnagar) against the larvae of the top borer, Scirpophaga excerptalis Walker. The recovery of the released parasite was poor and only a few cocoon masses of released parasite were recovered at IISR farm and Simbbaoli. The parasite, in spite of repeated releases for many years could not be established in the released areas. Parasitation and emergence behaviour of the wasp was also studied under laboratory conditions using field-coHected top borer - Infested canes. The wasp parasftised the top borer larva In the cane through the silken covering present over the slit formed during feeding of host larva. The wasp, after completing its development on host larva, emerged through tbe same silt.