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    Farming & Crop Protection Powdery mildew (apple)

    Powdery mildew (Apple) [Podosphaera leucotricha]

    Mildew is one of the most important diseases in fruit-growing, mainly occurring in dry, warm regions. In case of a severe infection, yield losses of 40% and above must be anticipated.

    overview

    Powdery mildew (apple) - image 1

    Powdery mildew (apple) - image 1

    Powdery mildew (apple) - image 2

    Powdery mildew (apple) - image 3

    Powdery mildew (apple) - image 4

    Pest Profile

    • About the pest

      Description

      Leaves and growing tips covered with a mealy-white, later with a gray-green mycelium layer (Pictures 1 & 2). Infected leaves point straight upwards and are rolled up (Pictures 3 & 4). Early shedding of leaves results in a balding of the shoots.

      Symptoms & Diagnosis

      Occurence

      The fungus overwinters in the growing tips and infects the newly formed leaves and inflorescences from there. The visible mycelium layer is the secondary infection during summer. Rains inhibits the fungi development.

      Treatment

      Combat

      The combination of mechanical and chemical measures is most effective. Affected shoots must be cut continuously. When the first symptoms occur, a fungicide program must be applied.