Leaf Damage Cause For Concern or Not?
Leaf damage on trees is highly seasonal and the amount of damage can fluctuate greatly from year to year. Insects, fungal diseases, and stress agents such as drought, heat, cold and excessive moisture can all create damage to leaves.
Below are a few things we have been noticing this year that appear to be to be showing up on our local trees more frequently than normal.
Spindle gall insects- This spring and summer we have seen lots of leaves on maples and lindens with small spike likeprotuberances called spindle galls. These are caused by a small insect called a mite. The mite feeds on the leaf and develops within the spindle and eventually hatches. Spindle galls are very noticeable but fortunately they don't cause health concerns to trees. If the unsightly nature of these growths causes aesthetic concern, treatment is available. Foliar applications can be applied in early spring before the spindles develop
Apple scab disease- Scab disease is a chronic problem of some varieties of crab apple trees. Some years are worse than others, and 2015 looks to be a banner year for the disease. Lots of rainy, wet conditions during the fungal spores infection period has created an abundance of fungal spores. This season is still early, yet many crab apples are already showing signs and dropping leaves early. Treatments are available and consist of series of foliar applications. Treatments are preventive, and work best when started before signs of disease. Our Hoppe Tree Service Plant Health Care Team can help you with a treatment program.
Early season leaf drop on ash- We fielded quite a few calls about ash trees dropping their leaves this spring. This has nothing to do with the Emerald ash borer insect. This phenomena is called ash leaf drop and it is actually a fairly common occurrence. Ash are one of the last trees to leaf out in the spring and generally ash leaf drop occurs right after leaf out. This cyclical event appears to be especially noticeable this spring. There is no real consensus from tree experts on why this occurs. Often it is caused by ash anthracnose fungusalong with a genetic response in the trees to drop some of their leaves. Many experts say "It's just what ash trees do." Luckily ash leaf drop doesn't significantly harm the health of ash trees. Most trees affected by early season leaf drop refoliate new leaves. If a tree is hit heavily in consecutive years it may cause problems. But seldom does ash leaf drop occur heavily two or more years in a row.
Other interesting things we have noticed this year
Poor flowering of red bud trees- Two years in a row with cold temperatures lasting into the early spring have caused another season with less than spectacular flowering of red buds. Most red bud trees seem to have rebounded from the slow start to spring though some are still experiencing weakness. General health treatments such as fertilization and soil amendments can help a weaker than normal red bud.
Excellent crab apple flowering- We've noticed wonderfully full, large and vibrant flowers on crab apple trees this spring. No one really knows why, but most likely our environmental conditions were just right to trigger widespread blossoming on these poplar plants. We'll take it!
Numerous silver maple seeds: Some tree species are genetically programed to periodically cast large amounts of seeds or fruit. This is an evolutionary response to keep predator populations out of synch. Spring 2015 has seen large amounts of silver maple seed. This tremendous outburst of helicopter seeds (properly called samaras) takes a lot of stored energy by the trees and some maples have exhibited weakness. We expect most trees to recover, though some silver maples may need additional help such as fertilization or soil amendments to aid in recover.