Cepas autóctonas de Bacillus subtilis como agente de biocontrol in vitro de Alternaria spp. en Brassica oleracea var. italica

The disease caused by the phytopathogenic fungus Alternaria spp., is one of the main causes of damages in broccoli crops in Ecuador, inducing losses of up to 30%. This research was carried out in order to determine the antagonistic capacity of native strains of Bacillus subtilis against Alternaria spp. by the means of in vitrotechniques. In the study, we used strains of Bacillus subtilis isolated, belonging to the main broccoli producing areas in Ecuador. Both pathogenic strains and antagonists were isolated and identified from soil samples randomly taken from broccoli crops in the provinces of Cotopaxi, Imbabura and Tungurahua. The antagonistic capacity was measured using the Bell's Scale. The results obtained indicate that the strain ATCC 6633 and strain AB-4 identified and characterized biochemically as Bacillus subtilis subsp. licheniformis, exhibit antagonistic activity with an average value of 45.21 cm Class 2 according to the Bell's Scale. These observationsestablish that Bacillus subtilis has a potential to act as a biological control against Alternaria spp.