~ 3030 ~ International Journal of Chemical Studies 2018; 6(3): 3030-3035 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2018; 6(3): 3030-3035 © 2018 IJCS Received: 20-03-2018 Accepted: 23-04-2018 Prasad PS Aicrp On Potato, Horticultural Research And Extension Station Hassan, Karnataka, India Amarananjundeswara H Aicrp On Potato, Horticultural Research And Extension Station Hassan, Karnataka, India Vishnuvardhana Aicrp On Potato, Horticultural Research And Extension Station Hassan, Karnataka, India Soumya Shetty Aicrp On Potato, Horticultural Research And Extension Station Hassan, Karnataka, India Sandhya GC Aicrp On Potato, Horticultural Research And Extension Station Hassan, Karnataka, India Correspondence Prasad PS Aicrp On Potato, Horticultural Research And Extension Station Hassan, Karnataka, India Management of late blight of potato by spraying botanical leachates and fungicides in southern dry zone of Karnataka Prasad PS, Amarananjundeswara H, Vishnuvardhana, Soumya Shetty and Sandhya GC Abstract 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. Keywords: Late blight, botanical leachates, fungicide and tuber yield Introduction 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 and caused yield losses up to 95 per cent in epidemic conditions (Lal et al., 2015) [6] . Late blight of potato is the major biotic constraint responsible for drastic reduction in yield and quality of the potato crop. An increasing severity of late blight in many potato growing areas, a shift in pathogen population towards increased specific virulence and an increasing tolerance to the most effective late blight specific fungicides suggests a need to develop an appropriate disease management strategy (Lal et al., 2017) [7] . Conventional control of late blight disease has mostly been tried by using synthetic fungicides, but repeated use of these chemicals has led to ecological hazards in addition to development of fungicide resistance in fungal pathogens. Globally, late blight is managed through application of multiple fungicidal chemical sprays affecting both human health and environment. Hence, economic and environment friendly approach for the effective management of potato late blight is need to be explored (Mirza et al., 2000) [8] . An use of different botanicals including neem (Azadirachta indica A. Juss) based preparations is innovative approach for the management of potato late blight. Keeping in view of the environment friendly nature, fungicidal properties and cheap availability of neem, its products were evaluated for their effectiveness against different growth stages of potato late blight pathogen Phytophthora infestans. Biological activity of the oil against P. infestans is probably because of this complex mixture of terpenoids like azadirchtin and its derivatives (Anonymous, 1991) [1] . But, Phytophthora infestans multiplies very fast under adverse weather conditions 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 practice for management of late blight of potato by spraying different botanical leachates, oils and