Potato Late Blight (<i>Phytophthora infestans</i>) Disease Management and Yield Loss Assessment in East Gojjam, North Western Ethiopia

Late blight potato disease (<i>Phytophthora</i> <i>infestans</i>) is the most devastating and causes 50–70% potato yield loss under favorable environmental conditions. Fungicide application is among the effective management options to control the disease. The experiment was conducted at Debre Markos agricultural research center station (Aneded) in 2023/24 main cropping season to evaluate the efficacy of fungicides to manage late blight disease of potato and to quantify the losses incurred duo to the disease in the area. Randomized complete block design with three replications was applied using Jalene variety to the experiment. Banjo forte 400 SC, Ridomil Gold MZ 68 WG, Electis 75% WG, Funguran-OH and Mancozeb 80% WP fungicides were used to execute the experiment. The highest 71.67 percentage severity and the lowest (12.69 t ha<sup>-1</sup>) marketable tuber yield were obtained from untreated plots, whereas the lowest (20.00%) percentage severity and the highest (27.54 t ha<sup>-1</sup>) marketable tuber yield were obtained from treatments treated with Redomil gold MZ 68 WG fungicide. Also the area under disease progress curve (AUDPC) was significantly reduced in treatments and the highest 1591.7% and the lowest 545.8% AUDPC value were recorded from untreated control and Redmil MZ 68 WG fungicide treated plots, respectively. This study showed the susceptible variety Jalene treated with Ridomil Gold MZ 68 WG and Banjo forte 400 SC fungicides were more economical and feasible for the management of late blight potato disease and increased yield.