Biocontrol of brown blotch of cowpea caused by Colletotrichum truncatum with Trichoderma viride

Trichoderma viride isolated from cowpea phylloplane hyperasitised the mycelium of Colletotrichum truncatum, causal agent of brown blotch disease of cowpea in vitro. T. viride treatment in the form of a seed dip in a spore suspension (10(8) conidia/ml) and soil drenching with a spore suspension were very effective in reducing infection from brown blotch infected seeds. Seed treatment with dry spores of the antagonist did not significantly reduce disease incidence compared to the control. T. viride as a spore suspension foliar spray applied once or twice weekly from three days after inoculation of cowpea seedlings with C. truncatum, significantly reduced brown blotch incidence in the field. These two treatments increased grain yield compared with inoculated unprotected plants. The yield from plots sprayed twice weekly with the antagonist was statistically comparable with inoculated plants sprayed weekly with benomyl. Copyright (C) 1996 Elsevier Science Ltd