Possibilities for Biological Control of Black—Shank Disease in Tobacco with Bacillus Cereus

ABSTRACT

This paper describes the results of trials carried out with a selected isolate of Bacillus cereus which was applied to tobacco seedlings (treatment of roots) in order to assess its effect as a potential tool for black-shank disease control in artificially infected soil. The roots of tobacco plants from several cultivars known to possess different levels of resistance to Phytophthora parasitica var.nicotianae, race O, were pretreated with either bacterial suspension or culture filtrate of B. cereus and then transplanted into soil infected by zoospores and mycelium from the fungus. The experiments were conducted under controlled conditions favouring the induction of disease symptoms. The data were expressed in terms of percentage of surviving tobacco plants. The isolate of B. cereus provided significant and durable protection against black shank disease. The data suggest the potential of B. cereus as an efficient agent in the biological control of black shack disease.