Assessment of the efficacy of powdered formulations of Bacillus spp. for the control of Alternaria sp., the pathogen responsible for leaf spot disease in cruciferous crops

Abstract

The efficacy of powder formulations derived from Bacillus spp. was evaluated using nine Bacillus spp. isolates: B1-19, B2-2, B2-6, B2-21, B2-32, A1-2, A1-5, A1-12, and A1-15. Each isolate was prepared in three different forms: cell suspensions, culture filtrate, and a combination of cell suspensions and culture filtrate, which were then developed into powder formulations. The results revealed that all three powder forms-cell suspensions, culture filtrate, and the combination of cell suspensions and culture filtrate were able to inhibit the colony growth of Alternaria sp., with inhibition rates ranging from 45.85–71.88%, 48.08–70.07%, and 47.52–70.07%, respectively.