ISOLATION OF SEED-BORNE AND SEED ASSOCIATED FUNGI OF Lablab purpureus (L.) SWEET AND THEIR BIOLOGICAL CONTROL

Abstract

Lablab purpureus (L.) Sweet is one of the most important and nutritious vegetables as well as pulse in Bangladesh and is grown extensively all over the country. It suffers from various fungal infections, which reduce greatly its quality and quantity. Seed-borne and seed associated fungi are one of the factors of substantial damages of the bean genotypes. Seed- borne and seed associated fungi of eleven genotypes of L. purpureus (L.) Sweet and their various controlling methods were studied. From eleven bean seed samples, seven types of fungal pathogens were isolated and identified. The most predominant fungi species were Aspergillus spp. followed by Fusarium sp. and Rhizopus sp. Comparatively less frequent fungi were Penicillium sp., Curvularia sp., Colletotrichum sp. and Alternaria sp. Plant extracts (Lawsonia inermis, Azadirachta indica and Allium sativum), cow urine, hot water and chemical fungicides (Bavistin, redomil and dithane M-45) were used to observe the efficacy of them against different species of fungi and their effect on germination rate and vigour index of bean seeds. Among the controlling measures, considering fungal infection controlling capacity, germination rate, vigour index as well as cheap, easy, environment friendly, easily available and easily applicable controlling measures, Azadirachta indica leaf extract was the best. Genotype GBLB-6, GBLB-11 and GBLB-13 showed more better performance through all the controlling measures and these genotypes may be used in the breeding program for their higher germination rate, higher vigour index and comparatively lower susceptibility to fungal pathogen.