Development of imidacloprid tolerant strain of Trichogramma chilonis Ishii

Imidacloprid tolerant strains of Trichogramma chilonis was developed by giving selection pressure to parasitoid at different incremental doses (started from 1/10^th of field dose to 1/4^th of field dose) of imidacloprid. T. chilonis was reared for 10 generations to develop tolerance to 1/10^th of field dose, 16 generations for 1/8^th of field dose, 18 generations for 1/6^th of field dose and 18 generations of T. chilonis were reared to develop tolerance against 1/4^th of field dose of imidacloprid. At F 62 generations T. chilonis developed tolerance to 1/4^th of field dose of imidacloprid with 27.94% mortality at 6 hrs of exposure and 76.67% parasitization and 78.99% adult emergence from the eggs of C. cephalonica. In consistency test, at F 62 per cent parasitization and percent emergence were 76.34% and 76.34% by tolerant strains, whereas, 16.67% parasitization and 19.67% emergence were given by susceptible strain at 1/4^th of field dose of imidacloprid.