VIEW ARTICLE

Ecology and Epidemiology

Potential of Gliocladium roseum for Biocontrol of Verticillium dahliae. A. P. Keinath, U. S. Agricultural Research Service, Plant Sciences Institute, Biocontrol of Plant Diseases Laboratory, Beltsville, MD 20705; D. R. Fravel, and G. C. Papavizas. U. S. Agricultural Research Service, Plant Sciences Institute, Biocontrol of Plant Diseases Laboratory, Beltsville, MD 20705. Phytopathology 81:644-648. Accepted for publication 3 December 1990. 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, 1991. DOI: 10.1094/Phyto-81-644.

A bioassay system was developed to evaluate fungi for biocontrol potential against Verticillium dahliae. Microsclerotia of V. dahliae were embedded in squares of nylon mesh. The squares were buried in nonsterile soil amended with preparations of the test fungi grown on vermiculite/wheat bran (3:1, w/w). After recovery from soil, viability of the microsclerotia was assessed by observing growth of V. dahliae on agar medium. Gliocladium roseum was the most effective species among 11 fungi tested. No viable microsclerotia were recovered from soils amended with G. roseum at a rate of 1.0% (w/w). The isolate of G. roseum used, the ratio of vermiculite to bran in the preparation, and the rate of antagonist preparation added to soil all significantly affected the viability of microsclerotia. The most effective isolate, G. roseum 632, significantly reduced the viability of microsclerotia by ?36% when grown on vermiculite/bran and added to soil at a rate ?0.01% (w/w). Three isolates of G. roseum, 632, W14, and Std, were effective in three different soils at –10 and –100 kPa soil matric potential. G. roseum has potential as a biocontrol agent of V. dahliae.