Effects of several fungicides on the Lolium endophyte in ryegrass plants, seeds, and in culture

Abstract

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 of the fungicides tested, 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 (‘Bay tan FI7’) or carboxin + thiram (‘Vitaflo 200’).

Key Words:

• Ryegrass
• Lolium endophyte
• fungicides
• propiconazole
• imazalil
• prochloraz