Isolates (21) of the bacterium B. subtilis isolated from local and exotic sclerotia of Sclerotium cepivorum were tested on cornmeal agar (CMA) for antagonism to 6 isolates of P. cactorum, causal agent of apple crown rot. All bacterial isolates produced diffusible antibiotics antagonistic to growth of all P. cactorum isolates on CMA. Antagonists were further evaluated in a replicated greenhouse trial for their ability to control crown rot infection on ''McIntosh'' apple seedlings in sterile soil. Six isolates of B. subtilis provided statistically significant reductions of infection on ''McIntosh'' seedlings. No correlation was observed between width of inhibition zone in vitro and protection from P. cactorum infections in ''McIntosh'' apple seedlings in a greenhouse trial. Significant negative correlations were observed between percent seedling infection and root weight.