Effect of Propiconazole and Tebuconazole on Seed Production of Tall Fescue

When stem rust (Puccinia graminis Persoon) invaded a tall fescue (Festuca arrundinacea Schreb.) stand a fungicide, propiconazole, applied at 250 g ai/ha, increased seed yields by more than l000 kg/ha compared with untreated plots. Propiconazole applied at ear emergence increased seed yields more than when applied at anthesis or at both times. Propiconazole significantly (P<0.05) increased seeds/spikelet and reduced leaf senescence during seed development and at harvest compared with untreated plots. Stem rust (Puccitiia graminis Persoon) severely infected the control plots but not the plots treated with propiconazole at ear emergence. In a second trial, when only a minor trace of stem rust was observed, propiconazole and tebuconazole did not affect seed yields of tall fescue.