Evaluation of bio-agents and neem based products against late blight disease (Phytophthora infestans) of potato

Abstract

Late blight disease incited by Phytophthora infestans (Mont) de Bary is a major limitation for potato cultivation. Organic based products are vital in organic cultivation; because these are non-hazardous and eco-friendly in nature. Few bio-products were evaluated against late blight on two popular potato cultivars in India like Kufri Bahar (highly susceptible) and Kufri Mohan (moderately resistant) in two consecutive years (2018–19 and 2019–20). All the seven treatments were found effective up to certain extent for managing the late blight disease. Among the bio-based products neem oil @ 6.0% showed lowest average terminal diseases severity (46.67%), followed by 64.67 and 66.67% with Pseudomonas fluorescens @ 1.0% and Trichoderma viride @ 2.0%, respectively on Kufri Bahar. The highest tuber yields was 28.23 t/ha with neem oil @ 6.0% followed by 28.10 t/ha with Trichoderma viride @ 2.0% against control (24.40 t/ha). Similarly, the lowest average terminal disease severity (27.25%) was recorded with copper hydroxide 53.8% DF @ 0.2%, followed by 28.50% with copper oxychloride 50% WP @ 0.2% on cv. Kufri Mohan. Among the bio-based products, minimum average terminal disease severity (30.92%) was recorded with neem oil @ 6.0% followed by 46.17% with Trichoderma viride @ 2.0% and 47.84% with fermented neem giri @ 1.0% on cv. Kufri Mohan. The highest tuber yields was 40.14 t/ha with copper hydroxide 53.8% DF @ 0.2%, followed by 39.68 t/ha with fermented neem giri @ 1.0% against control 34.64 t/ha. These evaluated treatments could be applied for managing late blight disease in organic cultivation of potato.