Apple tree damage

Asked August 26, 2019, 7:10 PM EDT

This damage is visible on the top of every limb on our Braeburn tree. It is also present on three other apple trees. Are trees are planted at about 1,600 FT elevation on a south-facing slope near Lyons Oregon. Any help will be greatly appreciated

Linn County Oregon apples

1 Response

Hi and thanks for contacting Ask an Expert.
Your picture looks like wood borer damage. The two wood borers that attack apples in this area that are most well known are shothole and Ambrosia wood borers. They are two different wood borers but go by both names.
The best advice would be to remove all the damaged wood, down to the good wood (cut on an angle so water doesn't sit on the newly cut limb) and burn all damaged wood. Clean up any debris on the ground including apples and limbs - burn them as well.
You can also spray with 100% Neem oil, do not use a mix as they may have added toxic chemicals. Follow the directions on the bottle. One quart will make gallons of spray.
I am attaching two articles for your review. The one from Washington State shows a trap that you can make which may help. The best thing to do is keep your trees as healthy as possible. Adding compost around the base of the tree (but not covering the trunk) and watering sufficiently will improve the health of the trees.
http://treefruit.wsu.edu/crop-protection/opm/shothole-borers/
https://pnwhandbooks.org/insect/tree-fruit/apple/apple-shothole-borer-ambrosia-beetle
If you find the shot holes in the bark, you can be pretty sure it is a wood borer, however, bacteria and fungi also may be living in the wood. Since you are at 1600 feet, did you have a freeze this last winter or the winter before 2019? That could have killed the limbs inviting disease into the tree tops. Whatever has caused this damage the diseased or pest infested limbs need to be removed and burned. Woodpeckers are your friends, pecking out the larva and beetles beneath the outer bark. Be careful with Neem oil, it will kill any insect it touches, but this time of year you shouldn't have pollinators in the apple trees. And, make sure you disinfect your cutting tools after removing the wood so you do not infect healthy wood should there be fungal or bacterial contamination. A cup of bleach in a bucket with some water works as a disinfectant. If you have any further questions, please do not hesitate to re-contact us.