Management of chocolate spot of Faba bean (Botrytis fabae) through fungicides and host resistance in North Shewa, Central Highland of Ethiopia

摘要

Abstract Faba bean (Vicia faba L.) production is limited by chocolate spot which can decrease yield up to 61%. Field experiments were conducted at Sayadebrnawayu district, Abaya Kebele during the 2018 and 2019 main cropping seasons with the objectives of identifying effective control measures for chocolate spot and to assess the effect of chocolate spot on faba bean productivity. The treatments included were four faba bean varieties with three fungicide sprays including one control. The 16 treatment combinations were arranged in a factorial randomized complete block design with three replications. On an average of variety and fungicide spray basis, higher final disease severity index (29.56%) was recorded during 2018 cropping season compared to 27.48% recorded during 2019 cropping season. On an average of year and fungicide basis, the final severity indices of 33.04, 29.21, 26.42, and 25.42% were recorded on the varieties of Wolki, Hachalu, Degaga, and Gebelicho, respectively. In addition, the final severity indices of 38.75, 28.04, 25.58, and 21.71% were recorded from control, Copper Hydroxide, Mancozeb, and Copper Oxychloride respectively. Areas under disease progress curves (AUDPC) were significantly (P < 0.001) affected by the interaction effect of variety with fungicide. The highest (1079.8%) mean AUDPC value was recorded from control plots of Hachalu while the lowest mean (601.4%-days) AUDPC value was recorded from the Degaga variety treated with Copper Oxychloride. Farmers need to use the integration of Degaga variety with Copper Oxychloride fungicide to combat the effect of the chocolate spot.