Enhancing in vivo foraging activities of Trichogramma chilonis Ishii and Chrysoperla zastrowi sillemi (Esben- Peterson) on eggs of Corcyra cephalonica Stainton through kairomonic activity of Helicoverpa armigera (Hubner)

Abstract

Bioassay of hexane extracts (1000 ppm) of male and female whole body, frass and larval wash of host Helicoverpa armigera (Hubner) against Trichogramma chilonis Ishii and Chrysoperla zastrowi sillemi (Esben-Peterson) revealed their kairomonal activities under in vitro condition. Treating irradiated eggs of Corcyra cephalonica Stainton with hexane extract of adult female whole body of H. armigera (1000 ppm) recorded the parasitization of 17.34 per cent by T. chilonis on third day after inoculation which increased from 50.64 to 64.28 per cent on fifth and seventh day after inoculation and they were 7.94, 21.76 and 32.58 per cent when the eggs were treated with hexane alone on third, fifth and seventh days after inoculation, respectively. Maximum emergence (48.16%) was observed with H. armigera female whole body extract followed by male whole body extract (39.33%). The highest predation by C. zastrowi sillemi on hexane extract of H. armigera female whole body treated eggs of C. cephalonica was recorded (61.13%) whereas it was 37.85 per cent in hexane treated eggs.