The adult white pine weevil is dark brown with white and tan patches on their backs and is approximately 8 mm long. They attack evergreen trees that are between 6– 25’ tall and there is only one generation per year.
What’s The Problem?
The weevils lay eggs on the leader of evergreen trees from late April to early June. The eggs hatch in 10 -14 days, the larvae eat their way downwards cutting off the water flow, and cause the leader to die. They remain in the stem for 5 – 6 weeks and emerge as adults from late July until early September. They will feed on branches and then move to the soil beneath the tree to overwinter.
What Can I Do?
Naturalized trees have a canopy protection and are less likely to be attacked than trees that are planted in the open. Providing shade and well drained soil results in a healthier environment. There are sticky substances available that can be applied to a band on the bottom of the trunk. This will trap some of the adults when they emerge from the litter at the base of the tree to crawl up the main stem. This does not provide complete control because the adults can also fly. As soon as you notice that the leader has been attacked (it will fall over like a shepherds crook) prune it off where the exit holes end and burn all pieces. You can train a new leader by attaching a stick or bamboo to the top foot of the tree and extend it past the top. Use a piece of Velcro, survey tape or other stretchy material to gently pull up the dominant side branch to be the new leader. The other lateral branches should be pinched back so there aren’t multiple leaders.