Chemical control of Sclerotium rolfsii Sacc.

José Henríquez S.1 y Jaime Montealegre A.1

The degree of in vitro chemical control of Sclerotium rolfsii utilizing the fungicides carboxin + thiram, iprodione, mepronil, oxicarboxin, pencycuron, procymidone, tolclofos methyl, triadimefon, triadimenol, tridemorf and vinclozolin was determined. The agar dilution method was employed and the effect of the fungicides was measured through the radial growth of the fungus mycelium, at 48; 72 and 120 hours after incubation at 27 ºC. The fungicides pencycuron, procymidone, tridemorf and vinclozolin, did not inhibit the fungus mycelial growth, being it, for the two first ones, just like the test. Iprodione showed an initial inhibitory activity of fungistatic kind, showing a great mycelial growth at 120 hours after incubation. The effective fungicides and its minimal inhibitory concentrations (MIC) were: carboxin + thiram 12.1 ppm a.i.; mepronil 40.5 ppm a.i.; oxicarboxin 40.3 ppm a.i.; tbiclofos methyl1.44 ppm, a.i.; triadimefon 41.7 ppm a.i. and triadimenol 36.6 ppm a.i. The effective fungicides, evaluated at its MIC's, were only fungistatic for the sclerotia of the fungus, it was observed even increasing 10 times such concentrations.

Keywords: fungicides, Sclerotium rolfsii, sclerotia, minimal inhibitory concentrations (MIC).
1 Facultad de Ciencias Agrarias y Forestales, Universidad de Chile, Casilla 1004, Santiago, Chile.