As samples come into the office, I make a point to highlight a few to keep a record and populate a website such as this with information local to our area. These pictures are from the central leader of a white pine collected locally from a tree that was infested by the White Pine Weevil. This is a less well-known pest but has been present in our area for several years now.
The short story here is that the weevil will over-winter in the duff and detritus under a tree and the following spring will find its way to the top of the tree where it feeds on the tissues of the central leader. This behavior is harmful and leads to the eventual demise of that portion of the tree but allows the tree to survive. “Cabbage top” results when new growth emerges often in the form of several new smaller leaders. Insecticidal treatments are available.
Other conifers besides white pine are susceptible. For tree farms, this can represent a commercial threat. Additional links for information are provided: http://bygl.osu.edu/node/368 and a fact sheet.
