Knowledgebase

Pest boring into top leader of pine #798424

Asked June 29, 2022, 6:11 AM EDT

Please help with identifying a boring pest who damages the top leader of pine trees.

Allegan County Michigan

Expert Response

Hello Jaclyn

What you describe sounds like damage from white pine weevil.

Here is what you can do now-

“It is important to inspect all pines and spruces for dying leaders now. Remove those damaged tops immediately and destroy them by burning or burying them. Do not drop them on the ground for the weevils to continue their life cycle at a lower elevation. The reason for the haste in removing dead leaders is that the longer they remain on the tree, the more damage can occur to those whorls below the dead leader.”


You can train a new leader by selecting a healthy shoot just below the pruned damage and splinting it to an upright position:

“Cut the terminal leader off 1 to 2 inches below the area damaged by the weevils. When you prune out the infested leader, make sure not to leave the cut terminals lying in the field because the larvae will continue to develop. After the dead leader is removed, select a healthy lateral shoot on the uppermost whorl to become the new leader. Trim the rest of the shoots back to one-half of their original length. This will enable the tree to recover its apical dominance and good form faster.”

Reference: https://www.canr.msu.edu/news/leader_damage_from_birds_and_weevils_showing_up_on_spruce_and_other_conifer

Pictures of splinting from Purdue Extension-


https://www.purdue.edu/fnr/extension/question-is-there-a-way-to-repair-the-tree-tip-of-my-pine-tree/


Here is prevention information for next spring-


https://www.canr.msu.edu/news/control_white_pine_weevil_in_early_spring


https://www.canr.msu.edu/news/white_pine_weevil_and_your_spruces_and_pines

If you cannot reach the top,safely, you can find certified arborists wih the equipment to do this for you- http://www.treesaregood.org


When using pesticides,please read and follow all precautions and directions.

Laura Sheffer Replied June 29, 2022, 9:21 AM EDT

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