Archive for Wednesday, July 2, 2008

Fruit-tree borers produce problems for area growers

July 2, 2008

If you've grown peach trees and other stone fruits, then you are likely familiar with the following scenario. You look in the orchard the morning after a windstorm and see a tree or two broken off just above the ground.

As a fruit grower, there can't be much more of a sick feeling. We should note that the tree is not to blame, as the likely culprit is the peach tree borer.

The peach-tree borer is a serious pest for any stone fruit producing tree as well as for ornamental, nonfruit-bearing varieties of those trees.

Today, I'll discuss the damage borers do and ways to prevent that damage from happening to your trees.

First I want to talk about what the borers do to the trees. The main reason borers are so damaging is, they tunnel in between the inner bark and the sapwood of the tree and feed on the bark. Their feeding stops the flow of water and nutrients through the tree, which eventually will injure or even kill the tree.

As if having your tree die isn't bad enough, the situation is more aggravating because borer damage is hard to detect. Unfortunately, it's likely the first time the damage is noticed is when the tree breaks off, and at that point, it's obviously too late to do anything to save the tree. The most important thing you can do for your tree is regularly check and spray for borers.

Don't depend on looking for holes in the tree where they entered, as borers like to use pre-existing cracks and wounds to enter the tree. This is why it's important to keep your trees healthy.

Avoid damaging trees with mowers and weed-eaters, keep the tree pruned, and water regularly during dry times of year. You should also control any other diseases and insects because these problems can make the tree more vulnerable to attack.

Even with insecticides, the peach-tree borer is hard to control because the adult borer is a moth that flies around looking for a place to lay eggs. The eggs eventually will hatch and turn into the actual borer that will damage your tree.

The lack of a control method proves especially problematic once they get into the tree, because the bark provides such good protection for them.

If you spray for borers, the time to do so in most of Kansas is in late June and then again in the last week of July. The spraying is targeted toward stopping the initial entry of borers into the tree. June and July are when the new hatches of borers are searching for a tree to enter and call home, so chemical application during that time is crucial in preventing infestation.

There are several choices of insecticide to use against borers, but most of the more effective ones are no longer available to homeowners. Permethrin is the best one that is still available to buy without a license.

Any insecticide that contains permethrin and is labeled to use on borers should be effective. "Hi-Yield Garden, Pet, and Livestock Insect Control", "Bonide Borer-Miner Killer", and "Gordons Bug-No-More Yard & Garden Insect Spray" are all labeled to work against borers.

Spray the lower 12 inches of the trunk and soil surrounding it until the tree and soil are wet with the spray. You should spray this portion of the tree because this is where the borers do their damage.

They work right at the soil surface a lot of the time, if not just beneath the soil surface in some cases.

Remember, you can contact me for questions at the Leavenworth County Extension Office on the corner of Hughes and Eisenhower roads in Leavenworth, or call (913) 250-2300. I can also be reached via e-mail at mepler@ksu.edu.

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