Light leaf spot forecast
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.
Issued each autumn by AHDB, the preliminary light leaf spot (LLS) forecast shows the proportion of the oilseed rape crop (disease resistance rating of 5) estimated to have more than 25% of plants affected by LLS in the spring for the current season. The forecast uses previous season pod incidence data and deviation from the 30-year mean summer (July and August) temperature. It also uses historic average winter rainfall data. In spring, the forecast is updated to reflect deviation in actual winter rainfall data from the 30-year mean.
The forecast provides a guide to seasonal risk levels. However, as local risk varies, it is important to inspect crops on a field-by-field basis, with prioritisation on early-sown susceptible varieties.
Light leaf spot final forecasts (2013–20)
Customised light leaf spot forecast (temporarily unavailable)
Also considers variety, sowing date and autumn fungicide applications,