oak mildew
(Erysiphe alphitoides)
A fungal disease of the soft tissues (recent leaves and shoot tips) of oaks (Quercus spp.) originating in the USA and first noted in England at the beginning of the 20th C. The fungus has a white powdery appearance.
This definition is abridged from A – Z of tree terms: A companion to British arboriculture.
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