The Q&A Archives: tree problem

Question: I have two apple or cherry blossom trees. Not exactly sure what type of tree it is. Maybe a japanese apple or cherry tree. They have small pink flowers that grow in clusters when they bloom. They seem to be rotting from the inside but are still very much alive. I dont want to have to cut the trees down...they are so beautiful in the spring. Is there something I can use to reverse this damage? I did notice the trees always have large black ants...could this be the problem?

Answer: It sounds as though you have cherry trees rather than apple trees. And, from your description of the problem, I suspect you're dealing with a disease called brown rot. The brown rot fungus can attack blossoms, fruit, leaves, twigs and branches. Disease symptoms appear in the spring after the blossoms open. Diseased flowers wilt, turn brown and are covered with masses of spores. The disease spreads into twigs causing small branch dieback. Profuse gumming may appear on infected branches. Fruit infections appear as soft brown spots and can engulf the whole fruit. Infected fruit and flowers shrink into "mummies" and may persist on the tree until next year.

Brown rot is caused by a fungus that over winters on infected plant parts. In the spring during wet weather masses of spores are produced that can infect the blossoms and young shoots. The disease will continue infection cycles during wet periods in the spring.

A combination of cultural methods and treatments are needed to control this disease in our wet rainy northwest climate.

Sanitation is very important. Remove and destroy all infected twigs and branches. Remove all rotted fruit.

To control, use wettable sulfur or copper during periods of wet weather. Or, apply three to four treatments of an approved fungicide (some are systemic) starting at bud break in the early spring and continue at regular intervals during the spring until dry weather. Thoroughly treat all leaf and twig surfaces. Treatments during blossoming are essential for good control. The wetter and rainier the spring, the worse the disease problem is. Also apply a dormant treatment before fall rains.

With a proper spray schedule you'll be able to control the disease and enjoy your lovely trees.

Black ants are most likely not part of the problem. They are feeding on the sap exuded by your cherry trees.

Best wishes with your trees!

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