Abstract

The ability of the antagonists Epicoccum nigrum, Gliocladium roseum and Trichoderma harzianum to reduce sporulation of Botrytis cinerea when applied after infection was investigated in bean-leaf-disc assays under a variety of environmental conditions. G. roseum significantly reduced sporulation of B. cinerea when applied up to 120 h after the pathogen, whereas E. nigrum and T. harzianum suppressed sporulation when applied up to 72 h after infection. When applied 48 h after infection, all antagonists reduced sporulation of B. cinerea at temperatures of 15–25˚C. G. roseum was highly effective at reducing sporulation of B. cinerea throughout this temperature range, but not at 10˚C, whereas E. nigrum and T. harzianum showed their greatest relative effects on sporulation at 25˚C. Antagonism by G. roseum was favoured by relative humidity of 98%, while the effect of relative humidity onE. nigrum and T. harzianum was equivocal. Under the conditions of the assay system, antagonist concentration did not have a consistent effect on reduction of sporulation.