VIEW ARTICLE

Disease Control and Pest Management

Effect of Soil Fungicides on Macrophomina phaseolina Sclerotium Viability in Soil and in Soybean Stem Pieces. M. B. Ilyas, Graduate Student, Department of Plant Pathology, University of Illinois, Urbana, IL 61801; M. A. Ellis(2), and J. B. Sinclair(3). (2)(3)H. G. Wright Graduate Research Fellow, and Professor, respectively, Department of Plant Pathology, University of Illinois, Urbana, IL 61801. Phytopathology 66:355-359. Accepted for publication 22 September 1975. DOI: 10.1094/Phyto-66-355.

The effectiveness of 10 soil fungicides in reducing viability of Macrophomina phaseolina sclerotia in soil depended upon the concentration of the fungicide used and exposure time. The most effective fungicides in laboratory tests in descending order were: benomyl, thiophanate-methyl, thiram, thiabendazole, triforine, and captan. There was greater reduction of sclerotium viability by all fungicides in low than in high organic-matter-containing soils. In laboratory tests, benomyl, thiophanate-methyl, thiabendazole, and thiram were effective in reducing sclerotium viability in soybean stem pieces placed in fungicide-treated soil. The reduction in viability was greater when free sclerotia were used, least when sclerotia were in fresh stem pieces, and intermediate when sclerotia were in partially decomposed stem pieces.