Pruebas Bajo Invernadero de Cepas de Bacillus Subtilis como Agente de Biocontrol de Alternaria Spp. En Brassica Oleracea Var Itálica

Broccoli is one of the most important vegetables in Ecuador, both for its consumption in the domestic market and considering that 65% of production is exported to international markets. The main disease affecting the crop is caused by the fungus Alternaria spp. This research evaluated, in greenhouse trials, two strains of Bacillus subtilis isolated from producing areas that had demonstrated effectiveness in controlling Alternaria spp. in previous in vitro tests. The strains, coded as IB6 and AB4, were activated from the strain bank of the Salesian Polytechnic University, and the pathogen was isolated from the producing areas. Inoculation with the pathogen began five weeks after transplanting at a concentration of 1 x 10⁴, and twelve hours later, B. subtilis was applied at a concentration of 1.2 x 10⁷. Antagonistic capacity was evaluated using a severity scale designed based on the number of lesions caused. A split-plot experimental design was used with a chemical control and an absolute control, quantifying the (ABCPE) until harvest and the severity of Alternaria spp in post-harvest florets, finding no significant difference between the IB6 strain and the chemical control.