Effects of several fungicides on theLoliumendophyte in ryegrass plants, seeds, and in culture

Abstract

The Lolium endophyte is the cause of ryegrass staggers in livestock. A range of fungicides, mostly systemic and many in the ergosterol-biosynthesis inhibiting group, was tested against the Lolium endophyte. Fungicides were sprayed on infected plants or applied as seed treatments to infected seed, and were also tested for their ability to inhibit growth of the fungus in culture at concentrations of 2.5-5000 ppm. The endophyte was resistant to many fungicides, and only propiconazole (Tilt) reduced the level of endophyte after foliar application. In culture, the fungus was most sensitive to prochloraz (Sportak), but showed some sensitivity to propiconazole and imazalil (Fungaflor). Prochloraz completely controlled the fungus in seed, and propiconazole gave good, but not complete, control. Both chemicals produced some phytotoxic effects. No control was obtained with seed treatments of triadimenol + fuberidizol (Baytan F17) or carboxin + thiram (Vitaflo 200).