Isolation and characterization of entomopathogenic fungi and their effectiveness

Abstract

An attempt was made to isolate and characterize native entomopathogenic fungi. newlineNine insect mycopathogens, belonging to seven genera were found naturally occurring in the newlinenine districts of Northern Karnataka. Morphological variation among the field collected isolates newlineof M. anisopliae (Ma2) and V. lecanii (Vl1) for various parameters like, hyphal and conidial newlinecharacters, sporulation and spore yield were recorded. Pathogenicity of V. lecanii to aphids, newlinewhitefly and mites and that of M. anisopliae to American bollworms and rhinocerous beetle newlinewas proved in laboratory. Among different carbon sources tested, starch proved superior for newlineboth the mycopathogens NH4 (SO4) and KNO3 were superior as nitrogen source. Bajra and newlinerice grains served as most productive media for conidial growth of Ma2 and Vl1 with an yield newlineof 22.77x108 and 24.59x108 conidia per g of media, respectively. Among pesticides tested, newlinefungicides showed maximum inhibition followed by insecticides and weedicides. The newlinepersistence of mycopathogens was higher in soil (upto 16 months) than in phylloplane (upto 3 newlinemonths). In general, all the carrier material had more conidial viability when stored in newlinerefrigerated and deep freezer condition and a reduction of more than 10 per cent and 8 per newlinecent in refrigerated and deep fereezer was observed after 150 DAS respectively. Oil newlineformulations proved better than wettable powder. newlineAmong the different concentrations of V. lecanii evaluated in laboratory against B. newlinebrassicae and Aleurodicus disperses, higher dosage of V. lecanii (1.2x109conidia/ha) was newlinefound effective with highest mortality of 92.30 per cent and 80.93 per cent on the 10th day newlineafter spraying respectively. A comparative account of efficacy of different isolates of V. lecanii newlineunder field conditions were evaluated against B. brassicae and A. crassivora. At the highest newlinedosage of all isolates (2x1012conidia/ha), Vl1 proved most potent against B. brassicae newline(61.16%mortality), whereas Vl3 showed better control against A. crassivora (66.50%). newline