Integrated management of faba bean gall ( <i>Physoderma viciae</i> ) disease using fungicide, host resistance and intercropping in northwestern Ethiopia

Abstract

Faba bean is an important food legume crop that is consumed in various forms of diets across the world, including Ethiopia. However, productivity of the crop is affected by faba bean gall (<i>Physoderma viciae</i>) disease in the highlands of Ethiopia. Field experiments were conducted to evaluate an integrated effect of fungicide applications, moderately resistant varieties, and intercropping on gall disease epidemic and yield of faba bean at Farta, Ethiopia, during the 2019 and 2020 cropping seasons. Three Bayleton (triadimefon) fungicide applications (foliar spray, seed treatment, foliar spray + seed treatment) plus a control, three faba bean varieties, and two intercropping systems with sole cropping were used as treatments and arranged in a split-split plot design with three replications. Significant (<i>p</i> &lt; 0.01) variations in gall disease components and faba bean yield were observed among treatments. Intercropping and the use of Bayleton applications in combination with the varieties Degaga and Tumsa reduced disease development and increased grain yield. The gall disease severity was reduced by spray applications at 90 days after planting. Intercropping of moderately resistant varieties Degaga and Tumsa with wheat and mustard significantly lowered the gall disease progression as compared to Bulga 70-wheat and -mustard intercropping in seed-treated plots. Integration of three sprays of Bayleton with Degaga provided the highest yield (5.27 t ha⁻¹), followed by integrating foliar sprays + seed treatment with Degaga (4.97 t ha⁻¹), and both treatments had higher net benefits than others in both years. Thus, integrating Bayleton as a seed treatment (1.5 g kg⁻¹ of seeds) with moderately resistant varieties Degaga and Tumsa in both sole and intercropping systems could be used as cost-effective and environmentally safe management options.