Integrated management of okra leaf spot caused by Alternaria chlamydospora

Abstract

Okra (Abelmoschus esculentus (L.) Moench) crop is being affected by several fungal, bacterial, viral and nematode induced diseases. However, leaf spot, caused by Alternaria chlamydospora has been common occurrence, causing quantitative as well as qualitative losses in okra. Therefore, in present study, four fungicides (two systemic, one each contact and combi-fungicide), bioagent T. viride and Neem oil were integrated by giving three srays at an interval of 15 days, for management of Alternaria leaf spot of okra (Hyb. NOH-1684). The experiment was planned and conducted in RBD with ten treatments replicated thrice, at the Department of Plant Pathology, College of Agriculture, Latur, VNMKV, Parbhani (MS), during Kharif, 2017. The results revealed that all the treatments significantly influenced leaf spot disease incidence, intensity, fruit parameters, fruit yield and incremental cost: benefit ratio (ICBR), over untreated control. Based on average disease intensity and its reduction over untreated control, the most effective treatment found was Carbendazim 25% + Mancozeb 50% WS @ 0.25%, with least average disease intensity (15.51%) and its highest reduction (50.09%), followed by Hexaconazole 5% EC @ 0.1% + Neem oil @ 0.2% (16.87% and 45.72%, respectively), Hexaconazole 5% EC @ 0.1% (17.45% and 43.85%, respectively) and Mancozeb 75% WP @ 0.25% + Neem oil @ 0.2% (17.58% and 43.43%, respectively). Rest of the treatments were found also effective. All the treatments also improved fruit parameters and fruit yield. Based on ICBR, the most economical and effective treatment found was Carbendazim 25% + Mancozeb 50% WS @ 0.25%, and Hexaconazole 5% EC @ 0.1% + Neem oil @ 0.2% (2.70), followed by Hexaconazole 5% EC @ 0.1% (2.60); whereas, it was least with Neem oil @ 0.2% (1.79).