Integrated management of late blight of potato

Abstract

Late blight of potato is the major biotic constraint responsible for reduction in yield and quality of the pota-to crop. Globally, late blight is managed through application of multiple fungicidal chemical sprays affecting both human health and environment. Now a days, methods of biological control are gaining importance as these are non-toxic and also environment friendly. However, Phytophthora infestans multiplies very fast; therefore, biological con-trol method alone is not a viable option to manage late blight. Hence, integration of both methods is essential. Eleven treatments consisting of biocontrol agents and fungicides were evaluated against the late bight in three consecu-tive seasons (2011-12, 2012-13, 2013-14) at ICAR-CPRIC, Modipuram. Meerut. The results revealed that the treat-ments ( T1 to T10) are effective for managing the disease up to certain level; however, lowest average disease se-verity (27.89%) was recorded in treatment when Bacillus subtilis (B5-0.25%) + Trichoderma viride (TV-0.7%) was applied before disease appearance followed by cymoxanil8+mancozeb 64%WP (0.3%) at onset of late blight and one more spray of B5+ TV after seven days. The next best treatment was application of B5+ TV before appearance of disease followed by metalaxyl 8+mancozeb 64%WP (0.25%) at onset of late blight and one more spray of B5+ TV against control (average disease severity 91.94%) with higher yield also except the treatment of three spray of mancozeb 75% WP (0.2%). These treatments could be integrated in farmer practices.