Fungicide Effects on Acremonium Endophyte, Plant-Parasitic Nematodes, and Thatch in Kentucky Bluegrass and Perennial Ryegrass. P. H. Dernoeden, Associate Professor, Department of Agronomy, The University of Maryland, College Park 20742. L. R. Krusberg, and S. Sardanelli. Professor, Department of Botany, and Laboratory Scientist, Department of Botany, The University of Maryland, College Park 20742. Plant Dis. 74:879-881. Accepted for publication 2 May 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0879.

Foliar applications of benomyl, chlorothalonil, iprodione, thiram, and triadimefon were assessed for possible nontarget effects on Acremonium loliae, plant-parasitic nematodes, thatch accumulation, and soil pH. Fungicides were applied monthly from April to September during 1983–1987 to field plots of Regal and Fiesta perennial ryegrass (Lolium perenne) and South Dakota, Merion, Sydsport, and Vantage Kentucky bluegrass (Poa pratensis). None of the fungicides significantly affected soil pH and only thiram enhanced thatch significantly when compared with untreated plots. Fungicides did not significantly affect population densities of plant-parasitic nematodes. Nematode species showed significant cultivar preferences: Xiphinema americanum and Hoplolaimus galeatus for Fiesta and Regal, Pratylenchus penetrans for Sydsport, Helicoty-lenchus pseudorobustus for South Dakota and Merion, and Tylenchorhynchus spp. for South Dakota and Vantage. Fungicides did not significantly reduce the percent of perennial ryegrass plants infected with A. loliae.

Keyword(s): turfgrass