Efficacy of Trichogramma chilonis Ishii in combination with biopesticides against Helicoverpa armigera (Hiibner) in rainfed cotton ecosystem

摘要

A study was undertaken to observe the combined effects of Trichogramma chilonis with some biopesticides viz., HaNPV, Bacillus thuringiensis var. kurstaki (Halt~(R) WP) and Beauveria bassiana (Bev Bas). Two releases of T. chilonis with two sprays of B.t.k recorded less mean larval population (0.33/plant), less damage on shed squares (42.78%), intact squares (9.12%), bolls (14.20%) and loculi (10.68%) and recorded higher yield (782 kg/ha). Two releases of T, chilonis with two sprays of HaNPV was the next best treatment regarding less mean larval population and damage on fruiting parts. Application of B. bassiana alone and in conjunction with T. chilonis proved less effective compared to other treatments. Two releases of T, chilonis with one spray of B.t.k or HaNPV and T. chilonis alone performed moderately in reducing the larval population and damage on fruiting parts.