Question

Cherry Tree Disease   QUESTION: As you can see in the attached photo the cherry tree has a white powdery (not sticky)disease covering the branches and trunk and causes the leaves brown and drop. This problem has occured for the last couple of summers but this year it is worse than ever.  We have sprayed for fungus and insects and used a granule insect killer but it has not stemmed the spread of the disease.  Can you identify this problem and give a possible solution?

ANSWER: Trees with powdery mildew have a white, moldy coating on leaves, flowers, buds and fruit. Young plants and trees are at an increased risk of powdery mildew, as this disease prefers tender, young shoots. Infected leaves can become distorted or curled and small flecks may appear in the leaves.I think you do not have a disease but an insect. More than likely cottony aphids or it could be cottony scale. IF the insect moves when touched it is an aphid if not than it is a scale. Treat either one with an insecticide called Orthene IF you can reach the infested areas. IF the tree is too large to spray with the Orthene then treat the soil around the tree with an insecticide called Bayer Advanced Tree and Scrub Insect Control. This is applied to the soil and the tree will take it to the leaves and twigs. and when the insect feeds it will be killed. It will take a couple of weeks for the insecticide to get into the tree's system and then another week or so for the control to take effect.  The spraying with the Orthene will be as soon as the spray hits the insects. The Bayer product will last for about 12 months. Check with your local garden type store for these products.

Here is a web link to the Bayer product.  http://www.bayeradvanced.com/tree-shrub-care/products/12-month-tree-shrub-insect

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QUESTION: Thank you so much for your response.  We do not see any insects anywhere on the tree.  We only see this white powdery substance.  if this is due to an insect then what is this substance - do the bugs create it as they ingest?

Answer
If you do not see any visible insects I would say you have a scale insect problem. Scales are tiny insects that live unde a shell (shell similar to a turtle). The white is a waxy substance produced by the insect. It in itself does not cause a problem but the scale can suck the energy out of the tree. I would treat the tree.