Evaluation of Different Strains of Trichogramma chilonis Ishii for the Suppression of Sugarcane Early Shoot Borer, Chilo infuscatellus Snellen

The efficacy of high temperature tolerant (PDBC strain) and Ludhiana (Punjab) strain of Trichogramma chilouis Ishii against early shoot borer Chilo infuscatellus Snellen was evaluated in farmers' field during 2004 and 2005. The PDBC strain was released from April to June @ 50000, 40000 and 30000 parasitoids/ha. and the Ludhiana strain @ 50000 parasitoids/ha. Nine releases of PDBC strain and Ludhiana strain @ 50000 parasitoids/ha were as effective as application of cartap hydrochloride (Padan 4G) @ 25 kg/ha in reducing the incidence of C. infuscatellus by 52.7 and 50.5% over untreated control, respectively. At lower two doses, the reduction was 29.03 and 34.7 per cent over untreated control and was significantly better as compared to untreated control and mechanical control (removal of dead hearts). The maximum parasitoid recovery (10.71% parasitization) was recorded with PDBC strain @ 50,000 parasitoids/ha and was on par with Ludhiana strain (9.88% parasitization) and significantly higher than that with lower doses of PDBC strain and control. Based on reduced pest incidence, higher parasitism and yield, the releases of T. chilonis (PDBC strain/Ludhiana) @ 50000 parasitoids/ha at 10 days interval from April to June can be successfully used for the suppression of early shoot borer.