Powdery Mildew Assessment Tool

PMapp is designed to assist the grape and wine industry to assess the disease powdery mildew on the surface of grape bunches. Powdery mildew affects wine quality and many Australian wineries have thresholds for tolerance, based on severity as indicated by the proportion of the bunch surface showing symptoms. PMapp comprises an assessment function, which allows the user to enter severity scores for powdery mildew as they assess each bunch. The screen shows a running total of bunch count, and cumulative incidence of disease (i.e. the percentage of bunches with any symptoms) and severity. Assessment results can be sent to a nominated email account for subsequent analysis. To assist assessment of powdery mildew severity, the user can access an image browser containing 139 images of grape bunches with areas shaded to represent a range of severity scores from 0 to 100%. The app also contains a key with increments in severity of 2% in the range 0-12% to assist users who wish to refer to a key. A self calibration facility is included to allow the user to assess their skills in estimating area and practise repeatedly to improve. Detailed instructions are provided and a contact email to send feedback.