Chemical Control of Sclerotium rolfsii on Golf Greens in Northern California. Z. K. Punja, Graduate Research Assistant, Department of Plant Pathology, University of California, Davis 95616. R. G. Grogan, Professor, Department of Plant Pathology, University of California, Davis 95616, and T. Unruh, Golf Course Superintendent, Del Paso County Club, Sacramento, CA 95821. Plant Dis. 66:108-111. Accepted for publication 8 May 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-108.

Eruptive and hyphal germination of dried sclerotia of two isolates of Sclerotium rolfsii on 1% Noble and Bacto water agar was totally inhibited by carboxin, cycloheximide, oxycarboxin, and experimental fungicide CGA-64251 in the agar at rates of 100 and 200 µg a.i./ml. None of the compounds, however, was fungicidal. Cadmium succinate, captan, chlorothalonil, thiophanatemethyl with zinc ion and manganese ethylenebisdithiocarbamate, mancozeb, pentachloronitrobenzene alone or with fertilizer, and furmecyclox in agar reduced germination of sclerotia by 80–95%. Benomyl, 2,6-dichloro-4-nitroaniline, thiram, triphenyltin hydroxide, vinclozolin, and experimental fungicide MF-647 had no significant effect on sclerotial germination. Applications of 2,6-dichloro-4-nitroaniline and cycloheximide in combination, captan, carboxin, pentachloronitrobenzene with fertilizer, ammonium bicarbonate, and ammonium sulfate controlled S. rolfsii under natural conditions when applied at 14-day intervals over a 3.5-mo period. Fungicides and nitrogenous compounds such as ammonium bicarbonate used separately or in combination may control S. rolfsii on turf.

Keyword(s): fungicide screening, southern blight.