Sclerotinia disease control in oilseed rape: disease forecasting, key risk factors and fungicide timing

摘要

Sclerotinia disease caused by the fungus Sclerotinia sclerotiorum is a recurring problem in the UK. Control relies mainly on foliar fungicides which prevent infection by spores. A simple weather-based infection model that produced 'alerts' for infection risk conditions up to 48 hours ahead, combined with crop growth stage assessments, was tested for control of sclerotinia stem rot in oilseed rape. Foliar fungicides were applied at times according to forecast alert dates during the susceptible crop phase (flowering: first flowers open through to end of flower) for four or five oilseed rape experiment sites each year, 2010 to 2012. Use of this model gave 76-96% control of sclerotinia stem rot disease, equivalent to the best control determined in retrospect with a standard fungicide timing. Other key risk factors were assessed for their importance as sclerotinia infection risk indicators. Within an individual field, the key factors were: forecast alerts from the weather-based infection model, rainfallintensity, and the percentage of petals with sclerotinia present.