Field efficacy of Chrysoperla cornea (Stephens) in combination with biopesticides against Helicoverpa armigera (Hiibner) on cotton under rainfed condition

摘要

The present investigation was carried out to study the field efficacy of Chrysoperla cornea (Stephens) in combination with biopesticides against Helicoverpa armigera (Hiibner). The lowest mean larval population of H. armigera, minimum damage on shed squares, squares (intact), bolls and loculi and higher yield were recorded in two releases of C cornea and two sprays of Bacillus thuringiensis var: kurstaki (B.t.k.) treated plots followed by C. cornea in conjunction with HaNPV and B.t.k alone treated plots, The field recovery of C. carnea, HaNPV infected, Bacillus thuringiensis var. kurstaki infected and Beauveria bassiana mycosed larvae was more in their respective alone treated plots. The incremental cost benefit ratio was obtained maximum in chlorpyriphos 20 EC alone (1: 3.66) followed by HaNPV alone (1: 3.50), two releases of C carnea with two sprays of HaNPV (1: 2.88) and two releases of C, carnea with one spray of HaNPV (1: 2.48).