Podosphaera aphanis

    Alternative names
    Strawberry Powdery Mildew, Sphaerotheca aphanis
    Description

    Podosphaera aphanis infects leaves, flowers, and fruit. Early foliage infections are characterised by small white patches of fungus growing on the lower leaf surface. On susceptible plants, dense mycelial growth and numerous chains of conidia (spores) give these patches a powdery appearance. Under favourable conditions, the patches expand and coalesce until the entire lower surface of the leaf is covered. In some strawberry cultivars, relatively little mycelium is produced, making it difficult to see the white patches. Instead, irregular yellow or reddish-brown spots develop on colonized areas on the lower leaf surface and eventually break through to the upper surface. The edges of heavily infected leaves curl upward. At times, dark round structures (cleistothecia) are produced in the mycelia on the undersides of leaves. These cleistothecia are initially white but turn black as they mature. The fungus also infects flowers, which may produce aborted or malformed fruit.

    Habitat

    Although sometimes known as Podosphaera aphanis affects a range of plants including Lady’s-mantle, Cinquefoil, Eucalyptus and Rubus species and may be found where any of these host plants are present.

    When to see it

    When the host plants are in leaf.

    UK Status

    Widespread in Britain.

    VC55 Status

    Status in Leicestershire and Rutland not known.

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    Leicestershire & Rutland Map

    MAP KEY:

    Yellow squares = NBN records (all known data)
    Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

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