Integrated disease management (IDM) strategies to check the late blight (Phytophthora infestans) disease apart from boosting the yield of potato crop

Late blight caused by the fungus Phytophthora infestans is the most important disease of potato that can result in crop failure within a short period, if appropriate control measures are not adopted. Despite the introduction of chemical, biological and host resistance strategies over years for controlling the disease, severe losses still occur largely because the effectiveness of these approaches is variable and often short lived. So, the present study was taken up by integrating or combining these strategies to control the disease. The different management components viz., tuber dressing with Dimethomorph, soil amendment with Trichoderma Viride and FYM, and foliar application of SAR chemical benzothiadiazole (BTH) and fungicides Dimethomorph 50WP and Mancozeb75WP alone as well as in alternation with each other were integrated and evaluated on two different varieties of potato i.e susceptible cultivar Kufri Jyoti as well as on a moderately resistant variety Shalimar-1 planted at two different locations in Kashmir viz Shalimar and Yarikha separately during 2017 cropping season. The results revealed that all the treatments proved effective in reducing the late blight incidence and intensity in comparison to control. The treatment with foliar application with either dimethomorph 50 WP or mancozeb 75 WP alone or in alternation with each other +foliar spray of BTH+ soil amendment (FYM+ T.viride) exhibited least blight incidence, intensity and A value (AUDPC) with concomitant higher yield gains and improvement in tuber grades followed by treatments which received foliar application of BTH +soil amendment (FYM + T. Viride) or soil amendment alone, whereas highest disease intensity, incidence and A value (AUDPC)with lowest yield and inferior grade tubers were observed in case of untreated control. Moderately resistant variety Shalimar 1 exhibited very less disease intensity, incidence and ‘A’value compared to susceptible cultivar kufri jyothi when provided with similar treatments at both locations i.e Shalimar and Yarikha in Kashmir.