Management of late blight of potato by spraying botanical leachates and fungicides in southern dry zone of Karnataka

Late blight of potato caused by an oomycete Phytophthora infestans (Mont.) de Bary is the most destructive disease of potato in hills and plain regions of India. It is mainly managed through application of multiple fungicidal sprays which affecting both human health and environment. Hence, economic and environment friendly approach for the management of potato late blight is need to be explored. Phytophthora infestans causal organism multiplies very fast and management through botanicals alone may not be that much effective. Therefore, an integration of both chemical and botanical methods is very essential. With the objective of identification of suitable integrated management practices for the management of late blight of potato by spraying different botanical leachates, oils and chemical fungicides in southern dry zone of Karnataka. The following experiment was initiated at HRES, Hassan with fifteen different botanical and chemical treatments during Kharif season 2015-17. The pooled data of three years indicated that, out of fifteen different treatments Fenamidone + Mancozeb @ 3 g/l documented highest marketable tuber yield of 16.09 t/ha with lowest late blight disease index of 11.21 per cent followed by Cymoxanil + Mancozeb @ 3 g/l with 14.45 t/ha of marketable tuber yield and 19.01 per cent of light blight disease index. However, treatment with combination of Neem cake leachates @ 20 g/l + Mancozeb @ 2.5 g/l spray was also found effective for the management of late blight of potato with 13.66 t/ha of marketable tuber yield and 21.33 per cent of late blight disease index.