Field Management of Anthracnose (Colletotrichum lindemuthianum) in Common Bean through Foliar Spray Fungicides and Seed Treatment Bioagents

Abstract

Common bean anthracnose is a major production constraint in bean growing regions of Ethiopia. This study aimed to determine whether foliar sprays of mancozeb, folpan and mancolaxyl or antagonistic bioagents; Trichoderma harzianum, Trichoderma viride and Pseudomonas fluorescens could reduce anthracnose symptoms and consequently, increase yield and yield components. A total of seven treatments were arranged in a randomized complete block design with three replications. Statistical analysis showed significant differences among treatments. Anthracnose incidence, severity, infected pods per plant and the area under disease progress curve were highest in the control plots compared to the fungicide sprayed and bioagent treated seed plots. The highest percentage of infected pods per plant, 78.9 and 55 were recorded on the control and mancozeb sprayed plots respectively. The highest AUDPC value resulted in the lowest yield of 1.01 t/ha in the control plots compared to a highest yield of 3.33 t/ha from the sprayed plots with folpan and 1.79 t/ha from plots treated with Pseudomonas fluorescens. Relative yield losses of 69.67, 46.25 and 22.82% were recorded from the control, seed treated plots with P. fluorescens and sprayed plots with mancolaxyl respectively. Economic analysis revealed that the highest rate of return of 8,740 was obtained from Pseudomonas fluorescens seed treatment and the highest net benefit; 43,154 on folpan foliar spray treatment. The results of the present study support the novel possibility of using folpan foliar spray and Pseudomonas fluorescens seed treatments to decrease anthracnose symptoms in bean plants and consequently, achieve greater yield.

Keywords: Bioagents; Folpan; Pseudomonas fluorescens; Mancolaxyl; seed treatment