Fungicide Application Frequency and Wheat Varietal Response to Yellow Rust ( Puccinia Striiformis f.sp. tritici ) Disease in Western Amhara, Ethiopia

Abstract

Wheat is a major staple crop in Ethiopia, but its productivity is severely constrained by yellow rust ( Puccinia striiformis f.sp. tritici ), the most economically important wheat disease. A rain-fed field experiment was conducted in 2019 in the mid-highlands of East Gojjam ( Goncha Siso Enesie district, Enesie Qole Kebele ) to evaluate integrated management options combining fungicide application frequency and varietal resistance. Three bread wheat varieties (Tay, Picaflor, and Kubsa) with differing reactions to yellow rust were tested under four Tilt 250 EC (propiconazole) application frequencies (0, 1, 2, and 3) in a randomized complete block design with three replications. Terminal disease severity was recorded at 18.2% for Tay, 23.0% for Picaflor, and 44.0% for Kubsa under untreated conditions. When fungicides were applied three times at 10?day intervals, the highest percent disease control (PDC) achieved was 59.2% in Tay, 52.9% in Picaflor, and 71.9% in Kubsa. Yield and thousand kernel weight increased significantly (p<0.01) with three applications: up to 40.9% and 27.7% in moderately resistant Tay, 48.3% and 55.2% in moderately susceptible Picaflor, and 41.2% and 70.4% in highly susceptible Kubsa. These results demonstrate that combining host resistance with optimal fungicide frequency effectively manages yellow rust in bread wheat. Further research is needed to deploy eco-friendly management strategies.