Ideas on a borer pest in pine tree nursery stock? NW Oregon

I have a conifer tree nursery. I grow several varieties of pine in northwestern Oregon, in the Willamette Valley. I have noticed pitch balls approximately 1.5-2" in diameter, close to the base. I see them predominantly on Shore and Austrian pines.

Under closer examination, I have found an insect entrance and what I think is pupae. It was brown and about half an inch long.

The trees are usually 2-3 inches in caliper. The trees were grown in pots, then planted in the field. I have noticed some twirling of the roots (rootbound), which may be stressing the plants.

I suspect it is some type of borer but I'd like help in ideas on figuring out which borer it could be. The trees are not dying and the infestation is very light.

Thanks in advance!

 

I would suggest you try to contact your local county extension office, they may have some insight. A good picture with size reference (a dime or penny) can be a great help to ID your pest. I am sure some of the members that are near to you will have some suggestions.

 

Oregon State University has an online guide to insect pests. Uncorrected binding of roots may become a problem later.