Evaluation of Fungicides and Bio-Agents against Ascochyta Blight (Ascochyta rabiei) of Chickpea under Dryland Conditions of Kashmir, India

Abstract

Five non-systemic fungicides: chlorothalonil, carbendazim (12%) + mancozeb (63%), captan 50WP, dodine 65WP and copper oxychloride 50WP and four systemic fungicides viz., difenoconozole 25EC, carbendazim 50WP, hexaconozole 5EC and mycobutanil 10WP were evaluated against Aschochyta blight of chickpea caused by Ascochyta rabiei. The in-vitro evaluation of non-systemic fungicides through poisoned food technique at five different concentrations: 50,100, 250, 500 and 1000 µg ml-1 fungicides showed that carbendazim (12%) + mancozeb (63%) proved most effective and resulted in highest mycelial growth inhibition (82.27%) of the pathogen followed by dodine with mycelial growth inhibition of 67.99%. The least efficacious fungicide was copper oxychloride with only 29.81% mycelial growth inhibition. Among the systemic fungicides evaluated at concentrations of 25, 50, 100, 200 and 500 µg ml-1, carbendazim proved to be the most effective and caused highest mycelial growth inhibition of 90.23% followed by difenconozole (71.24%). Myclobutanil 10WP was least efficacious among the systemic fungicides and resulted in only 52.76% of mycelial growth inhibition. Among the three methods used for evaluation of efficacy of fungicides and bio-agents, revealed that the seed treatment with carbendazim (12%) + mancozeb (63%) proved most effective with lowest disease incidence (15.0%) and disease intensity (4.02%). Among the biological control agents used, seeds treated with Bacillus subtilis proved the most effective which resulted in disease incidence and intensity of 32.25 and 20.04%, respectively. Combination treatment comprising of seed treatment with Bacillus subtilis at concentration of 109spores ml-1 and foliar spray with mancozeb 63% WP+ carbendazim12%WP at the concentration of 2.5% was most efficacious and resulted in lowest disease incidence (7.80%) and disease intensity of (4.82%) while seed treatment with Bacillus subtilis at the concentration 109 spores ml-1alone was least efficacious and resulted in highest disease incidence of 53.80% with disease intensity of 37.25%. It was, however superior than control where disease incidence and intensity was 80.00% and 51.34 %, respectively.