Pine Weevil readying for attack: time to fight back
Published at | Updated atWhite pine weevil, also called spruce weevil, is a very common pest in East Idaho. This beetle-like insect especially likes to prey on ornamental spruce trees, like Colorado blue spruce and others. While you may see damage any time of the summer, it is treated in the spring so if you have damage it is important to think about treatment right now.
How much damage can a little bug do?
Pine weevils feed on the bark around the very top of the tree (called the terminal shoot). They also lay their eggs about 18 inches from the top of the tree and the larvae will feed under the bark during the summer, causing the top to wilt into a shepherd’s crook-like shape. This is a key indicator that you may have pine weevils.
If left unchecked, other buds will compete to fill the void, causing a forked top. Two or more leaders (the vertical stem at the top of the trunk) on a spruce tree weakens its structure and can create a hazard tree that will need to be removed or it could break. If those new leaders are continuously attacked by pine weevil, it will result in a stunted and bushy tree instead of the natural tall, narrow form.
What can you do about pine weevil?
In the fall, adult pine weevils crawl down the tree and burrow into the soil around the base of infected trees. When temperatures warm up in the spring, they will emerge and crawl up to the top of the tree to feed. If treated with an insecticide early in the spring you can kill the adults before they get up the tree and have a chance to lay eggs for the next generation.
Timing is very important, as is selection of the right insecticide. If you apply insecticide yourself, make sure that the label mentions pine weevils specifically. However, the most effective products to treat pine weevil are only available to licensed applicators, so hiring a professional may be easier than treating it yourself.
If you are unsure if you have pine weevil, you can contact an ISA Certified Arborist to diagnose the problem and recommend a course of treatment. Many trees will respond well if it is caught before too much damage has been done.
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