Seed Mycoflora of French Bean and its Control by Means of Fungicides

Abstract

Seeds of two varieties of French bean (Phaseolus vulgaris L.) Pusa Parvati and Lakshmi were examined after harvesting for external and internal mycoflora using agar plate and blotter methods. Overall 26 species were isolated from all varieties by both techniques. The most common fungi were noted to be Alternaria alternata, Curvularia lunata, Cladosporium cladosporioides, Rhizopus nigricans, Aspergillus niger, A. flavus, Penicilliun citrinum, Trichoderma viride and Dark sterile mycelium. The blotter technique proved to be better in comparison to the Agar plate technique. The prominent field fungi recorded were Alternaria sp., Curvularia lunata, Drechslera avanacea, Cladosporium cladosporioides, Fusurium sp., Aspergillus spp. and Penicillium spp. during the summer season from fresh seeds. Most of these field fungi were replaced by the storage fungi in winter season e.g. Aspergillus niger, A. flavus, Trichoderma harzianum and Penicillium. The effect of different concentrations of four common fungicides viz. Dithan M-45, Bavistin, agrasan, GN and PCNB was studied on seed mycoflora and seed germination of two varieties of French bean. All the fungicides used were found to be effective in reducing the seed mycoflora. The percentage of all the treated seeds which germinated was higher than the untreated ones, so the fungicide enhanced the seed germination rate by controlling the seed mycoflora.