VIEW ARTICLE

Ecology and Epidemiology

Comparison of Antagonists of Sclerotinia Species. P. B. Adams, Biocontrol of Plant Diseases Laboratory, Plant Science Institute, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705; Phytopathology 79:1345-1347. Accepted for publication 24 July 1989. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1989. DOI: 10.1094/Phyto-79-1345.

Eight reported antagonists of Sclerotinia spp. were evaluated for their ability to destroy sclerotia of Sclerotinia minor in soil. When sclerotia of S. minor were soaked in concentrated spore suspensions of the antagonists for 3 hr and added to moist natural soil, Teratosperma oligocladum caused a 94% reduction in the inoculum density of S. minor within 10 wk. Dictyosporium elegans and Coniothyrium minitans were intermediate in reducing the number of sclerotia after 30 wk, whereas Penicillium citrinum, Talaromyces flavus, a Trichoderma sp., and Gliocladium virens were ineffective. When sclerotia of Sclerotinia sclerotiorum were soaked in concentrated spore suspensions of the antagonists for 3 days and then added to moist natural soil infested with sclerotia of S. minor, only T. oligocladum reduced the inoculum density of S. minor. When various concentrations of spores of the antagonists were added to moist natural soil infested with sclerotia of S. minor, only Sporidesmium sclerotivorum and T. oligocladum reduced the inoculum density of S. minor. These two mycoparasites were effective at rates of 10–14 spores per gram of soil, whereas the other antagonists were ineffective at rates as high as 10⁶-10⁷ spores per gram of soil. It was concluded that S. sclerotivorum and T. oligocladum are aggressive mycoparasites, whereas the other antagonists are passive mycoparasites.