The Incidence and Seventy of Eyespot on Winter Wheat Variety Hereward Grown as a Monocrop and as a Bicrop With White Clover

Abstract

In a three-year field trial, the level of eyespot on cv. Hereward winter wheat was recorded from cereal monoerops and cereal-clover bicrops receiving standard farming practice and reduced levels of input. Disease incidence (for years one, two and three) and severity (years two and three only), increased with each season in all treatments. In the third wheat crop the area under the disease progress curve (AUDPC) for disease incidence (mean of all treatments) was 3.30 times higher than that measured for the first wheat crop. The average AUDPC for disease severity in year three was l.78 times greater than that for year two. In year three the eyespot incidence AUDPC for bicrops was 1.12 times greater than in monocrops. Disease severity AUDPC in year three was MS times greater in bicrops than in monocrops. For all treatments there was a significant correlation between AUDPC and the rate of disease increase. The results are discussed in terms of those factors that are likely to affect eyespot levels within bicrops, especially microclimate changes, spore production on crop residues, and spore dispersal by rain-splash.