Hello, Angela!

In order to prevent damage from the White Pine Weevil you will need to be on the lookout for early signs of infestation. Depending on the infestation level, you have options to prune and destroy the damaged shoots or to use pesticides.

Starting in late April through late May the female weevil moves up the tree, after overwintering in the leaf litter on the ground, and feeds on the terminal leader. She lays her eggs in the wounds she makes as she eats. If a tree is infected, you will see that the leader has numerous small holes in the bark with leaking sap/pitch.

Pruning – Inspect all pines and spruces for dying leaders in April and May. Remove damaged tops and destroy them by burning them. It is important not to drop them on the ground as the weevils will then continue their life cycle at a lower elevation on the tree. Infested leaders can be pruned out taking care to prune as soon as you see a problem to prevent more extensive the damage. More information about pruning can be found here:

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

Chemical Application/s – Using a contact insecticide can be used as a preventative and is especially helpful for large infestations. Timing is key. Pesticides are applied in late March/early April in order to kill the adult weevil before it lays the eggs.

Soil drench – For smaller trees, a soil drench using a product with the active ingredient of imidacloprid

Contact pyrethroid insecticides – For larger trees, a spray using a product with the active ingredient of bifenthrin, permethrin or cyfluthrin. This is directly sprayed on the leader, avoiding the rest of the tree to conserve beneficial insects. A second application is applied 2 weeks later.

Insecticides containing Dimilin – This product is less harmful to pollinators and beneficial insects but is a restricted use pesticide and is only available to certified pesticide applicators. Find these professionals by zip code search here- http://www.treesaregood.org