Agricultura (Dec 2018)
EFFICACY OF FUNGICIDES AGAINST LATE BLIGHT OF POTATO
Abstract
Potato varieties grown in Nepal have low levels of general resistance to late blight. Mostly the commercial potato farmers rely on fungicide applications for control of Phytophthora infestans, the causal agent of late blight. Field study was conducted in winter 2017 at research field of Institute of Agriculture and Animal Science, Lamjung Campus, Sundarbazar, Lamjung, Nepal to evaluate the efficacy of commercially available fungicides against late blight of potato. Experiment was laid in randomized complete block design with five replications. Treatments consisted of Dimethomorph 50% [email protected]/L, Cholothalonil 75% WP @ 2g/L, Mancozeb 75% WP@ 2.5g/L and Trichoderma @ 2ml/L as recommended for field use and a variant with no application of fungicide (only tap water) was used as a control. Spore suspension of respective plant pathogen was inoculated twice @ 500 ml per plot (4m2). Treatments were applied after the appearance of first blight symptom and level of disease development was followed. The best control was obtained with application of Dimethomorph with significant reduction in AUDPC (139 dsu) while the control treatment gave the highest AUDPC of 223.2 dsu. Same pattern was seen for tuber production where application of Dimethomorph gave 170.8 g tuber/plant, which was significantly higher than that of control treatment (73.7 g). Chlorothalonil and Mancozeb gave the intermediate level of disease control still significantly superior than control treatment. However; the application of Trichoderma showed the AUDPC of 228 dsu with 89.7 g of tuber yield per plant which was statistically indifferent with the control treatment. Thus, this study recommends Dimethomorph 50% [email protected]/L in controlling the prevailing strain of P. infestans and multi-location trial is necessary in future for general validation.
Keywords
