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    Farming & Crop Protection Powdery mildew (grapevine)

    Powdery mildew (grapevine) [Uncinula necator]

    A heavy infection may lead to shedding of the affected leaves and bursting of grapes. There may be up to a 60% harvest loss. When the first infection is visible, the disease become difficult to control.

    overview

    Powdery mildew (grapevine) - image 1

    Powdery mildew (grapevine) - image 1

    Powdery mildew (grapevine) - image 2

    Powdery mildew (grapevine) - image 3

    Powdery mildew (grapevine) - image 4

    Pest Profile

    • Symptoms & Diagnosis

      Occurence

      The fungus is very common in Europe but does not occur every year or with equal intensity at every site. Warm weather and dense, leafy populations enhance the risk of infection, the first infections can occur in mid-May.

      Pattern of damage

      Upper sides and undersides of leaves are covered with a mealy gray-white fungal layer (Picture 1). A whitish fungal cover can also be seen on the green grapes (Picture 2). All green plant parts may be affected. In the course of the summer, the affected spots turn dark gray.

      Treatment

      Combat

      Pruning of vines (removal of affected wood) and an early fungicide treatment prior to and during florescence are necessary to control the fungus.