Controlling of Maize Grey Leaf Spot by Interacting Host Resistance and Fungicide Spray Frequency at Bako, Ethiopia

Abstract

Grey leaf spot (Cercosporazeae-maydis) is major disease affecting maize in western Ethiopia. At Bako National Maize Research Center, a field condition study was conducted to examine the interaction between maize varieties and fungicide spray frequencies on maize GLS and yield, to assess maize yield loss due to GLS, and to conduct cost-benefit analyses of using various fungicide frequencies on maize GLS. The experiment was set up as a factorial combination of 3 maize varieties with 3 tilt 250 EC spray frequencies in a randomized complete block design with 3 replications. The difference between the mean yield of protected plots and unprotected plots of each variety was used to calculate grain yield losses. Finally, correlation and economic analysis were done. Unsprayed variety BH543 had the highest AUDPC value (1676.27%-day), terminal PSI (68.33%), and disease progress rate (0.044500 units-day-1) scored. GLS caused grain yield losses of up to 52.82 % on untreated variety BH543. PSI, AUDPC, incidence and disease progress rate were negatively correlated with yield. The highest marginal benefit (ETB 60486 ha-1), and marginal rate of return (ETB 18.05) were obtained from variety SPRH with once application of propiconazole. Based on current results, one-time tilt 250 EC application was found effective to manage GLS on SPRH1 variety. However, additional experiments should be carried out to verify the current results.

Keywords

• cercosporazeae-maydis,,
• ,،fungicide spray frequency,,
• ,،interaction,,
• ,،varieties,,
• ,،yield