The effect of propiconazole on foliar fungal diseases, herbage yield and quality of perennial ryegrass

Abstract

The fungicide propiconazole, applied as a foliar spray to swards of perennial ryegrass ( Lolium perenne) at four sites in England from 1990 to 1992, reduced the incidence of powdery mildew ( Blumeria graminis), Drechslera leaf spot ( Drechslera spp.) and Rhynchosporium leaf blotch ( Rhynchosporium spp.), increased the number of leaves per tiller and reduced the proportion of dead leaves. Propiconazole increased yield, by 6–7%, at harvests in mid-May, but had no effect at harvests in late June, when the cut herbage was dried to produce hay, although in one hay crop, in vitro organic matter digestibility was increased from 575.6 to 588.5 g kg −1 ( P < 0.05). Further research is required to determine the rationale and optimum timing of fungicide application to grassland.