Late blight (Phytophthora infestans) management with fungicide and varietal combination of potato at Fagita Lekoma, North Western Ethiopia

摘要

Abstract Phytophthora infestans is a destructive disease in potato growing areas of Ethiopia. The experiment was conducted at Fagita Lekoma district during 2019 main cropping season to evaluate the effect of variety and fungicide combinations for late blight. In the study four potato varieties and two fungicides were used. Fungicide applications was started soon after the appearance of late blight symptom and continued at weekly intervals. The field experiment was laid out in factorial arrangement in Randomized Complete Block Design with three replications. The highest disease incidence (100) at 52 day and PSI (76.68 and 63.92) at 87 day was obtained from unsprayed plots of Key and Zengena varieties, respectively. Whereas, the lowest disease incidence and Percentage Severity Index was obtained from Belete and Gudene varieties both sprayed with Ridomil Gold 68 WG. The maximum disease progress rate (0.0930unit day− 1) was obtained from unsprayed plots of Key variety. On the other hand, the lowest rate (0.0405unit day− 1) were calculated from Belete variety sprayed with Ridomil Gold 68 WG. Maximum yield (31.66 t ha− 1) was gained from Belete variety combined with Ridomil Gold 68 WG. The highest MRR (1631.18) obtained from local Key sprayed with Ridomil Gold 68 WG. The maximum net profit was obtained from Belete variety sprayed with Ridomil Gold 68 WG. Therefore, combination of moderately resistant variety Belete with fungicide applications, especially Ridomil Gold 68 WG is better for the management of late blight and sustainable production of potato for the study area.