Fungicide control of stripe rust in wheat protection or eradication

Abstract

A springsown field trial at Lincoln in the 2001/2002 growing season assessed the relative protectant and eradicant activity of the fungicides azoxystrobin and epoxiconazole for control of wheat stripe rust caused by the fungus Puccinia striiformis The fungicides were applied at different stages of a stripe rust epidemic nil disease trace of disease or moderate disease on five wheat cultivars which differed in susceptibility to the disease Disease severity and host reaction were also measured The mean area under the disease progress curve (AUPDC) of flag leaves of the susceptible cultivar Tiritea was reduced by 65 after application of azoxystrobin and by 37 after application of epoxiconazole The AUDPC for the moderately susceptible cultivar Karamu was reduced by 4150 by both of the fungicides The more resistant cultivars Impact Sapphire and Otane had very low AUDPCs and would probably not benefit from an application of fungicide to control stripe rust unless the pathotype present was highly virulent against these cultivars Depending on disease pressure fungicides on susceptible cultivars should be applied at or near flag leaf emergence