Effectiveness of Trichogramma Chilonis Ishii in the Suppression of Chilo partellus (Swinhoe) in Summer Maize

Studies on the effectiveness of Trichogramma chilonis Ishii in the suppression of Chilo partellus in summer maize were carried out at Punjab Agricultural University, Ludhiana during summer 2006 and 2007. The mean total incidence of maize stem borer was minimum in maize plot with single release of T. chilonis @ 100,000/ha on 12-day-old crop (14.3%) followed by 15-day-old crop (153%) and incidence in these two was significantly lower as compared to untreated check (33.0%) and proved effective in reducing the incidence of maize stem borer and subsequently increased the maize yield. However, the pest incidence in all biocontrol treatments was higher than the maize plot treated with deltamethrin 2.8 EC @ 200 ml ha^-1 (10.5%). The yield obtained from maize plot with single release of T. chilonis @ 100,000/ha on 12-day-old and 15-day-old crops (25.9 and 25.4 q ha^-1 , respectively) was significantly higher than all other treatments except maize plot treated with deltamethrin 2.8 EC @ 200 ml ha-1 (26.2 q ha^-1 ). The parasitism rate of C. partellus eggs on maize plants was significantly higher in releases of T. chilonis @ 100,000 ha^-1 on 12- and 15-day-old crop (44.8 and 43.1%, respectively) as compared to untreated check (4.4%) and plots treated with deltamethrin 2.8 EC @ 200 ml ha^-1 (1.0%).