Gary W. Moorman, Professor of Plant Pathology
|Crown gall||Rough galls form on stems at the soil line or on roots. If the galls engulf the stem or root, that tissue will be killed.||Agrobacterium tumefaciens||Remove severely affected trees. Do not replace them with herbaceous or woody plants susceptible to crown gall.|
|Black canker||Black areas form on leaves and spread to engulf and kill larger woody twigs in the summer. If the weather is wet, pink spore masses form on blackened twig cankers. This disease often occurs on trees with blight. See below.||Phyalospora miyabeana||Do not plant highly susceptible cultivars in the landscape.|
|Blight or scab||Newly formed leaves and twigs are quickly browned in the spring during wet weather. Infected leaves fall. Olive-brown spores form on the surface of infected tissue.||Venturia saliciperda||Applya fungicide to protect the foliage of highly valued trees.|
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Warning! Pesticides are poisonous. Read and follow all directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams or ponds.
Issued in furtherance of Cooperative Extension work, Acts of Congress, May 8 and June 30, 1914, in cooperation with the U. S. Department of Penn State College of Agricultural Sciences research and extension programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture.
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