Question
leaf pictures
We planted an October Glory Maple tree last year in the fall. I recently noticed the leaves have spots on them making them look similar to a watermelon. In addition, some of the newer leaves are turning brown around the edges. What is causing this and can we do anything to help prevent it from harming our tree? We live in Central Indiana. Thanks for your help!
AnswerThis is Leaf Blister of Maple. The culprits are fungi in the genus Taphrina. One species has caused spectacular symptoms on silver and red maples over the past month or so. Grayish brown, sometimes rounded spots often cluster around the main veins of leaves. Heavily spotted leaves can become twisted and drop off the tree, which is when the blister problem may become obvious. The blister effect may not always be clear on these spots, but the spots are sometimes raised or curved.
The leaf blister fungi spend the winter in the scales of the leaf buds, so they are ready to rumble as soon as the leaves peek out in the spring. When you have spring weather as wet as in 2009 , it抯 a perfect setup for a leaf blister outbreak.
Despite their unpleasant appearance, the leaf blisters are not a threat to the health of trees. There are no repeated cycles of infection during summer rains, and the trees pretty much shrug off the annoyance of some blistered leaves. In fact, fallen leaves are usually replaced by trees within a few weeks. Even though 2009 was a banner year for blister spot diseases, they are fairly rare in so-called normal springtime weather.
The bottom line for management is that there almost never a need to do anything. The leaf blister diseases can run their course without chemical warfare or other homeowner responses.
If you have a beloved specimen tree on which you refuse to allow a bit of cosmetic damage, you can apply a single fungicide spray in the spring, just before bud break, to prevent the spots. A number of products containing the fungicide chlorothalonil will be effective and are available in most garden centers.
If this disease becomes a problem several years in row, or in three of the last five years, homeowners may wish to plan ahead and apply a preventative fungicide just prior to budbreak next year. Several fungicides that are labeled for home use for control of Taphrina diseases and include: ?Lime sulfur
?Chlorothalonil (Bravo, Daconil)
?Bordeaux mixture
?Fixed Copper (Kocide, Top Cop)
