Effects of fungicide rates and timing on control of stripe rust in wheat

Abstract

A field trial was conducted to evaluate control options of stripe rust in a 1997/98 crop of spring sown Otane wheat near Methven. Three fungicides were evaluated for disease control, at half and label recommended application rates and at three timings. Disease levels were assessed at five dates. Plots were harvested and yield components recorded. In this trial where stripe rust appeared relatively early, the first spray had the greatest effect on disease severity. All three fungicides reduced disease severity compared to the untreated plots but azoxystrobin reduced disease more than epoxiconazole or tebuconazole. A full application of any of the three fungicides at application time 1 gave similar disease control to two half rate applications (Time 1 plus Time 2 or Time 3). Yield was significantly increased by both azoxystrobin and epoxiconazole at application Time 1.