Integrated control of strawberry powdery mildew

Strawberry powdery mildew (Podospheara aphanis) is a major disease of protected strawberry crops. The disease can cause losses of between 20 and 70%. Many cultivars are susceptible to the disease but are widely grown because other factors for example fruit quality, ease of picking, etc. are very important factors for growers when they choose the cultivars to plant. Work at the University of Hertfordshire has shown that a 'continual, integrated' approach to disease control gives satisfactory results. The over wintering stage of the fungus, the chasmothecia, play an important role in disease carry over but their viability and number can be greatly reduced by the use of a fungicide in August/September. All crops, whether overwintering or planted in spring are likely to have disease on them, and this can be reduced by a fungicide spray used before the fleece/ mulch is put on. The use of a silicon nutrient in the fertigation tubes throughout the growing season delays the onset and severity of disease epidemics. The silicon nutrient modifies the leaf and petiole morphology thus reducing fungus penetration of the leaf. The use of a risk prediction system based on in tunnel temperature and humidity measurement also enables epidemics to be controlled with fewer fungicide sprays. This full season approach to controlling strawberry powdery mildew results in lower disease levels achieved with the use of fewer fungicides.