and branches and trash them. Try collecting some of the galls and storing them in a plastic bag in a shady place and watch for when the adult insects emerge. Then spray the affected tree if it not too large. Synthetic Insecticides for Trees and Shrubs
Leaves stippled, yellowing or bronze, dry out and (drop)may be webbing visible, sometimes galls form on leaves
Oak Mites - Oak mites are about 1/50 inch long, barely visible to the unaided eye. Resembling tiny spiders, they have four pairs of legs, piercing-sucking mouth parts, and very compact bodies. They may be yellow, green, red or brown. If the top surfaces of the lower leaves on the Oak tree are stippled with small yellow dots or red spots, it is likely that mites are the cause. Look for fine webbing over leaves, their stalks and adjacent stems. For more information see the file on Controlling Mites
Leaves turn bronze, wilt, drop
Oak Wilt, A Fungal Disease -
Most Oaks are susceptible to this systemic fungal disease, although members of the Red Oak group are hit harder than White Oaks. It is spread mostly by insects such as beetles or borers, by man, or even by squirrels. It enters the tree through wounds in the bark. Often it is inadvertently carried by arborists or foresters on their tools. Trees are most vulnerable during their early spring growth period as they develop new wood. The fungus causes the leaves to turn a sickly bronze color. Soon they wilt and eventually fall off.
This disease is prevalent in the north-central, mid-Atlantic and mid-Western regions of the United States. There is, as yet, no reliable treatment. Researchers are working on a promising fungicide.
Dealing With Oak Wilt
Of special concern these days is anyone owning one or more oak trees. Usually oak trees need no pruning except when they are damaged in a storm. The very serious concern is to do any repairs to storm damage on your oaks before April 1st. If an oak is pruned even just a little bit from April through July or even August, it is exposed to the very serious threat of a disease called “oak wilt”.
This fungal disease very often occurs in oaks if they have been pruned in the warm months. The stakes are very high. Any oak infected by oak wilt will die in one or two months. It is a disease found in every county in Michigan and is easily as serious as the Dutch elm disease that wiped out most of America’s elm trees in the last century.
The red oak family is the most vulnerable to oak wilt. That includes red oak, scarlet oak, black oak, and pin oak. The white oak family is a little less vulnerable but can still contract this disease. The white oaks include white oak, swamp oak, and burr oak. If any of these trees are in your yard and are in good health, they are not likely to have any problems with oak wilt. The fungus does not enter a tree with no damage. A good reason to have your oaks checked by a professional arborist every three or four years is to ensure ongoing health of those very valuable shade trees.
growth spurt--roughly April through July. Take care not to bring firewood into the yard which may be infested with insects that are carrying the fungus.