Investigations on tritrophic interaction in integrated management of okra pod borer complex

Abstract

Investigations on tritrophic interaction, screening of okra accessions against pod newlineborers, bio-efficacy of biorationals, evaluation of marigold as trap crop and development of newlineIPM modules for the management of okra pod borer complex were carried out at Agriculture newlineResearch Station, Main Agriculture Research Station and Narendra village of Dharwad district newlineduring 2004-05 and 2005-06. newlineIn tri-trophic relationship, parabhani kranti, Shakti-303, Shagun and Rasi-5 were least newlinepreferred hosts for oviposition for all three pests and permitted greatest parasitisim by the egg newlineparasitoid, thereby resulted in least per cent egg hatching. However, on the contrary newlineMahalaxmi-Amisha, Ankur and L-177 supported highest oviposition and least parasitism by newlinethe parasitoid due to their higher trichome density. Irrespective of accessions trichome density newlinewas positively correlated with oviposition preference while parasitism was negatively newlinecorrelated. newlineAmong different accessions screened, accessions shakti-303, Shagun and Rasi-5 newlinewere recorded lowest pod borer incidence and produced 33.38, 26.41 and 22.95 per cent newlineincrease in yield over commercial check Arka Anamika. newlineAmong different bio-rationals, NSKE 5%, econeem plus (1000 ppm), Beauveria newlinebassiana + econeem plus (1000 ppm) and B. bassiana at 2g/l were found to be superior by newlineregistering less number of eggs and larvae of Earias vittella (Fab.) and Helicoverpa armigera newline(Hubner) which resulted in lowest per cent pod damage and highest yield of 68.91, 67.78, newline67.44 and 60.57 q/ha, respectively and were comparable with the standard check malathion newline50 EC (71.17 q/ha). newlineAmong different row proportions used, okra + marigold at 10:2 and 10:1 proved to be newlineeffective in reducing the pod damage and produced highest yield of 61.28 and 54.97 q/ha, newlinerespectively. newlineAdaptable IPM (M2) module involving biorationals and selective insecticide was found newlineto be effective and resulted higher net profit of Rs.57926 compared to rest of the modules newlinetested.