The maps displayed on this site are generated through a reliable computer model based on accurate weather data collected from serveral sites throughout each region. The powdery mildew index is an indication of climatic conditions which may be conducive to development of powdery mildew disease. It is possible to have the disease present and active at economically damaging levels even when the powdery mildew index indicates a low likelihood of conditions favoring rapid development of the disease. Frequent field scouting by a qualified PCA is recommended.
Disease Model Database Control of Powdery Mildew Using the UC Davis Powdery Mildew Risk Index