Evaluation of fungicides for management of late blight (Phytophthora infestans) of potato

Late blight disease of potato, causal agent, Phytophthora infestans (Mont.) de Bary, is one of the serious diseases for potato production. Application of fungicides is an effective management option to control late blight. Field experiment was conducted during winter season of 2018 for evaluation of the efficacy of fungicides on late blight management and potato yields in research field of Prithu Technical College, Institute of Agriculture and Animal Science, Gadawa, Lamahi Dang, Nepal. Six fungicides i.e. Relaxyl (Metalaxyl 8% + Mancozeb 64 %), Antracol (Propineb 70 %), Sectin (Mancozeb 50% + Fenamidone 10%), Dithan M 45 (Mancozeb 75 %), Targon (Metalaxyl 35%), Bavistin (Carbendazim 50 %) and a nontreated control (NTC) were replicated three times in a randomized complete block design planted with late blight susceptible potato variety Cardinal. Fungicide application considerably reduced late blight progress, with a corresponding increase in tuber yield. The least disease severity (18.67%), least disease incidence (5.33%), least mean AUDPC (85.56) and highest tuber yield (9.49 kg/plot) were recorded on application of Sectin @ 2 g/L. The disease incidence and AUDPC value was negatively corelated with the tuber yield. The result revealed that the fungicide Sectin was most effective in controlling late blight disease of potato and to increase tuber yield.