Bacillus-based biological control of cotton seedling disease complex

To formulate an efficient and eco-friendly strategy for the management of cotton seedling disease complex, pot experiments were conducted and the efficiency of eight Bacillus strains against seven fungi involved in the disease were determined. A greenhouse evaluation of the interaction between fungal isolates and Bacillus strains was carried out. The evaluation revealed a very highly significant Bacillus strains x fungal isolates interaction for all the following parameters: preemergence damping-off, postemergence damping-off, survival, plant height, and dry weight. This interaction implies that a single strain of the Bacillus sp. can be highly effective against a fungal isolate, but may have only minimal effects on other fungal isolates. The results of the present study demonstrated that Bacillus circulans and B. coagulans were the most effective strains in controlling cotton seedling disease. Therefore, strains of Bacillus spp. should be tested against as many fungal isolates as possible. The testing will improve the chance of identifying Bacillus strains effective against several fungal isolates.