Management leaf spot of field bean (Lablab purpureus L.) caused by Alternaria alternata (Fr.) Keissler

Abstract

In present studies, 18 genotypes of field bean were screened under natural epiphytotic conditions in field against Alternaria leaf spot at Dapoli (M.S) location revealed that, disease intensity was less in DPLW-2010-7-4-1-31 (25.24 %). Maximum disease intensity was observed in DPLW-2010-6-1-1-8 (32.76 %). Remaining germplasm entries recorded the intensity in range of 26.93 % to 31.72 %. All the germplasm lines screened against Alternaria leaf spot were moderately susceptible. Among the fungicides evaluated in vitro, propiconazole 25 % EC @ (0.05 %) recorded complete inhibition of growth of the test fungus. Thiophanate methyl 70 % WP (0.1 %) was found to be less effective and it recorded mean colony diameter of 47.2 mm and also lowest per cent reduction over control (47.55 %). Field evaluation of different fungicides revealed that, propiconazole 25 % EC (0.05 %) was found most effective with least terminal disease intensity (12.57 %) and maximum yield of 11.11 q ha-1. It was followed by difenconazole 25 % EC @ 0.05 % (13.94 %).