Evaluation of interaction effect of fungicides and potato (<i>Solanum tuberosum</i> L) varieties against late blight (<i>Phytophthora infestans</i>), disease in Chilga District, Central Gondar, Ethiopia

Abstract

Potato is the fourth most important food crop in the world. Late blight potato disease is the major bottleneck problem in the Chilga district. This study was designed to find out the integrated use of potato varieties and fungicides for the management of late blight disease. Three improved varieties (Belete, Jalenie, Gudenie) and one local variety combined with two fungicides (Agro-Laxyle MZ 63.5WP, Cozaxyle 72% WP) were used as a treatment combination. The experiment was laid out in Randomized Complete Block Design (RCBD) in factorial arrangement with three replications. Data on first disease symptom appearance date, disease incidence, percentage severity index, and disease progress rate were recorded according to standard procedures. The highest (98.15%) percentage severity index and the lowest (4.53 t ha-1) marketable tuber yield were obtained from the highly susceptible local varieties untreated plots, while the lowest (22.59%) percentage severity index and the highest (41.63 t ha-1) marketable tuber yield were obtained from the relatively resistant Belete variety treated with Cozaxyle72% WP fungicide. This study showed the relatively resistant Belete variety treated with Cozaxyle 72% WP fungicide was more economical and feasible for the management of late blight potato disease and increased yield markedly.