Alternaria leaf spot control using soil-derived Bacillus spp biological agents in GLP 2 Phaseolus vulgaris L
Phaseolus vulgaris L is considered one of the most essential legume crops in Kenya. Alternaria alternata is an economically significant plant pathogen that causes Alternaria leaf spot which accounts for over 70% yield losses of beans in Kenya. Chemical fungicides based on copper and sulfur are used to control Alternaria leaf spot in bean plants, but prolonged use has adversely affected the environment and the health of workers. Herein we tested the biocontrol potential of bacterial agents from soil planted with Rose Coco bean plants infected with A. alternata. Using biocontrol suspensions at different time intervals, we evaluated the putative bacterial biocontrol activity against A. alternata under greenhouse conditions. B. subtilis and B. velezensis bacterial biocontrol agents significantly suppressed disease severity of 20% and 21.2% on the 45th day respectively. Our study demonstrates that B. Subtilis and B. Velezensis are promising biocontrol agents that could be integrated in the management of Alternaria leaf spot.