Light leaf spot in oilseed rape

Producing more than one infection cycle per season, light leaf spot is an important disease of winter oilseed rape. Although chemistry is available, sufficient control often depends on a combination of cultural measures and well-timed sprays.

Light leaf spot is an important disease of winter oilseed rape in the UK, as well as in Germany, France and Poland. The pathogen is usually more serious in Scotland and the North of England. However, incidence varies considerably between years and regions, driven largely by weather. Infection may result in leaf loss/distortion, stunting and pod shatter. In the absence of fungicides, yield losses may be as high as 1 t/ha. The disease also affects vegetable brassicas and related weed species.

Leaves, flowers, stems and pods may all show symptoms of light leaf spot infection. With management centred on timely detection and understanding disease pressure, recognising the tell-tale signs of this disease is essential.

Understanding the factors that influence disease risk is the first step in light leaf spot management. Through cultural control, monitoring and carefully considered fungicide applications, it is possible to suppress the threat from this major foliar pathogen.