Prune out witches brooms when they form. Powdery mildew causes a white powdery growth on the leaves. If the disease occurs late in the season, no chemical control will be needed. Try to prevent cankers by keeping trees healthy through watering during dry weather and regular fertilization. Avoid wounding the trees unnecessarily and prune out weak or dead branches.
Verticillium wilt kills individual branches or sometimes entire sections of the tree.
Foliage on affected branches wilts and later turns brown. Keep trees healthy and prune out small infected branches. This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. This information becomes public property upon publication and may be printed verbatim with credit to MSU Extension.