Pathogenicity of Trichoderma spp. on the sclerotia of Sclerotinia sclerotiorum

Abstract

One isolate of Trichoderma viride, 12 of T. koningii, 5 of T. harzianum, 11 of T. pseudokoningii, and 9 Trichoderma spp. obtained from 15 soils by baiting with the sclerotia of Sclerotinia sclerotiorum were tested for pathogenicity and aggressiveness in vitro and in field soil against the latter. Five isolates of T. koningii, two of T. harzianum, three of T. pseudokoningii, and one of an unidentified species killed 62–100% of the sclerotia within 25 days when tested in vitro. Two isolates of T. koningii killed 100% of the sclerotia within 7 days. One isolate of T. koningii killed 100% of the sclerotia within 60 days under field conditions, when soil was infested with 104, 106, or 108conidia/g. The rate of decline was more rapid at inoculum level of 106 and 108conidia/g of soil than at 104.