The Release of Trichogrammatoidea armigera parasitoid for the Parasitization of Helicoverpa armigera Eggs in Maize

Background: Helicoverpa armigera (Hübner) is a common polyphagous pest on corn cob. H. armigera that is controllable through Trichogrammatoidea armigera (Nagaraja) parasitoid release. Successful inundated release of parasitoids depends on parasitization and parasitoid dispersal. Methods: The experiment consisted of 2 parasitoid release plots and 1 no release plot. T. armigera parasitoid was released twice, at 45 DAP and 52 DAP (Day after planting) in the middle of the experimental plot. The dose of parasitoid released during the corn generative phase was 1000 individuals per 254 m2 (~ 40000/ha). Evaluation was carried out by collecting the eggs of H. armigera 3 days after release at radius 1, 3, 6 and 9 m in all cardinal directions from the release point. Result: The release of parasitoids increased the eggs parasitization of H. armigera in 45 DAP tot he tune of 51.91% and 52 DAP was 38.57%. The wind direction did not affect the parasitoid movement which is active and almost uniform in all cardinal directions. Parasitoid movement was slightly similar in all distances and cardinal directions. The distribution of parasitoids reached 9 m from 40 release points ha-1 in colonies. T. armigera parasitoids were grouped hence, the monitoring in corn was carried out systematically.