Efficacy of Selected Bioagents against Alternaria Leaf Spot of French Bean (Phaseolous vulgaris L.)

Abstract

French bean (Phaseolous vulgaris L.) is a significant food, legume crop utilized as a pulse and green vegetable crop, belongs to family fabaceae. The French bean is a cool-season, day- neutral vegetable that can withstand extreme temperatures. Area, production and productivity on French bean in India (2019-20) were 22.1 Mha, 2226 million Tonnes and 7-10 t/ha. They are high in protein and have a similar texture to meat. Green pods have 1.7 g protein, 0.1 g fat, 4.5 g carbohydrate, 1.8 g fibre, and are high in minerals and vitamins in a 100 g serving. Several diseases affects French bean crop majorly and cause yield loss Alternaria leaf spot (Alternaria alternata), Angular leaf spot (ALS) (Phaeoisariopsis griseola), Bean rust (Uromyces appendiculatus), Anthracnose (Colletotrichum lindemuthianum), Aschochyta leaf spot (Ascochyta phaseolorum) and Cercospora leaf spot (Cercospora canescens). Among them, Alternaria leaf spot of French bean is one of the most severe disease, which is caused by A. alternata in the French bean. An experiment was conducted in the Zaid season to check the efficacy of bioagents against A. alternata on field conditions. Bioagents viz.,Trichoderma viride, Pseudomonas fluorescens, Bacillus subtilis as seed treatment. An untreated replication served as control. Among the treatments, the maximum germination percentage maximum plant height (cm) at 90 DAS , maximum no. of primary branches and secondary branches at 60 DAS was recorded in T4 – T. viride @2.5%+ P. fluorescens @ 2.5% followed by T1 – T. viride @ 5% as compared to untreated check control T0 . The minimum disease intensity (%) at 75 DAS was recorded in T4 – T. viride @ 2.5% + P. fluorescens @ 2.5 %, followed by T1 – T. viride @ 5% as compared to untreated check control T0.