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Subject: New North American record for Sawadaea bicornis, a powdery mildew, on Norway maple (Acer platanoides)
Date posted: March 26, 2003
Source: Plant Disease 87:451
In September of 2002 the first North American report of Sawadaea bicornis was found on Norway maple, Acer platanoides, trees along the Idaho-Washington state border. The powdery mildew was only found on young trees. This fungus has been recorded on many species of maple throughout Europe but never in North America. Norway maple is a hardy urban shade tree that is widely planted in the United States and Canada. Damage by powdery mildews is not usually fatal but heavy infestations will hasten defoliation and reduce overall plant vigor.