WITHDRAWN: Split release of egg parasitoid, Trichogramma japonicum Ashmead for biocontrol of rice yellow stem borer, Scirpophaga incertulas in Chhattisgarh plain of central India

Abstract

Abstract Yellow stem borer (YSB), Scirpophaga incertulas Walker is considered as major pest of rice. An egg parasitoid, Trichogramma, is used for management of lepidopteran pests of rice worldwide. In order to optimize the time and number of releases of Trichogramma under field condition in Chhattisgarh plains, three different schedules of releases (each consisting of four split releases of wasps) of Trichogramma japonicum Ashmead were tested to manage YSB during rainy season 2017 and 2018 (June to October) under field condition. Each schedule was split into four releases of wasps (50,000 wasps/ha/release × four releases or 500 wasps/100 m2/release × four releases). The statistical analyses of two seasons data revealed that four split releases of T. japonicum at weekly interval on the 32nd, 39th, 46th and 53rd day after transplanting of rice had resulted the reduction of damage caused by YSB over control of 52.8% (2.51%) dead heart and 66.1% (0.62%) white ear in comparison with control (5.32% dead heart; 1.83% white ear). The results suggest that the time-specific four split releases of T. japonicum @ 50,000 wasps/ha/release × four split release can be the useful to attain biocontrol of YSB.