Abstract
In view of the ecological hazards of fungicides, a greenhouse study was conducted to determine the efficiency of seven Bacillus isolates against 32 isolates of Macrophomina phaseolina. Bacillus isolates, M. phaseolina isolates, and their interaction were all highly significant sources of variation in infection (damping-off), plant height, and dry weight. The highly significant (p=0.0000) of Bacillus isolates x M. phaseolina isolates interaction implies that a single isolate of the antagonist can be highly effective against an isolate of M. phaseolina, but may have minimal effects on the other isolates ofM. phaseolina. Therefore, isolates of the antagonist should be tested against as many isolates of M. phaseolina as possible, as this will improve the chance of identifying antagonist isolates effective against several isolates ofM. phaseolina.