Validation of biocontrol technology for suppression of sugarcane top borer, Scirpophaga excerptalis (Fabricius) with Trichogramma japonicum Ashmead in Punjab

The efficacy of Trichogramma japonicum released @ 50, 000 per ha at 10 days interval for the management of sugarcane top borer, Scirpophaga excerptalis, was validated at four locations in Punjab during 2009 and 2010. The mean incidence of top borer in T. japonicum released fields (6.2%) was at par with chemical control (5.8%) but lower than no release (control) (13.7%). The mean parasitism of eggs of S. excerptalis in released field was 32.1 per cent as compared to 2.5 percent in chemical control and 3.0 per cent in no release (control) plots. The mean yield in released plots (717.6 q/ha) and insecticide treated plots (725.1 q/ha), were significantly higher than the control plots (645.8 q/ha). The cost: benefit ratio for T. japonicum (1:21.5) was wider than for chemical control (1:6.8).