I sent a note to Russell P. Kidd
District Extension Forestry Agent asking for something on why the white oaks around this area were losing thier leaves. I thought it was simply a frost event. NOT!
CONTACT: MSU Extension office, 275-5043
DATE: June 13, 2001
RELEASE: Immediate
MOTHER NATURE CAUSING CONFUSION
ABOUT LOCAL OAK TREE PROBLEMS
Within the last few weeks, area newspapers have carried articles alerting area residents about a new, potentially threatening disease called oak wilt. This disease, which attacks mainly Red Oaks, causes a very rapid shutdown and wilting of an oak tree within a week or so – especially noticeable in early July or so. It is such a difficult problem to deal with after a tree becomes infected with oak wilt, that a dedicated effort was made this year to start educating area residents about this disease. The main message of those news articles was that people can help limit spread of oak wilt by NOT pruning or injuring their oak trees from April through July.
Unfortunately, this spring, Mother Nature has dealt the area with ANOTHER tree problem that is much more widespread than the oak wilt disease. This problem is called oak anthracnose which is caused by a fungus that attacks the leaves of primarily White Oak trees. Once attacked, a portion of a leaf becomes blighted, curls up and shrivels in some cases. The most severely blighted leaves may actually fall off the tree and litter the ground.
Oak Anthracnose is particularly severe this year because of all the rainfall we had this spring. Development of this disease is highly favored by wet, cool temperatures which is exactly what the area has experienced this spring. The fungal spores that carry this disease to newly expanding leaves thrive under wet, cool conditions. The Anthracnose disease has essentially “run its course” for this year. No new leaves should become infected at this point in time. Chemical fungicide control is possible, but trees should have been sprayed at budbreak in
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in anticipation of this problem. Therefore, spraying is not an option at this point. While anthracnose does stress trees slightly, the best course of action now is to give these trees some additional “TLC” by watering if it ever becomes droughty and to fertilize trees or lawn areas under trees soon if you haven’t done so this year. Also, residents may be able to help minimize possible infections next year but doing a good job of raking up the leaves of these infected trees this autumn and composting them off-site away from these trees.
The severity of Oak Anthracnose closely follows the weather patterns that exist each spring. If people recall what the weather has been over the last five years or so, they might remember that the springs of 1997 and 1998 were overall warm, dry springs. Anthracnose was not a widespread problem during those “El Nino”-like years. Last year, anthracnose began to build-up in the area because the weather last year was wetter than the previous years. This year it has become worse because of the presence of disease spores coupled with the prolific rainfall we experienced this spring. In other words, this disease will cycle and not be continuously bad each year.
For more information about either Oak Anthracnose or Oak Wilt, please contact the MSU Extension office at 275-5043.
