Identify Insect

Question: What insect makes this circular object under the bark of Pondersoa Pine trees?

responder: An Ask Extension Expert Replied April 17, 2023, 1:27 PM EDT
response: Hi there,  We are hoping to get some more information so that we can try to answer your question: What is the history of the tree? Approximate age, size, location. Could you please provide another photo from a bit further back so that we can get a sense of scale? Where is this issue located on the tree? Was there a branch at that site at any point in time?  Thank you.  Best regards, Cindy Master Gardener Apprentice

responder: The Question Asker Replied April 17, 2023, 6:49 PM EDT
response: Thank you for your reply.  Here is some background information.  The trees involved are mature Ponderosa pine, living at 8,000 feet elevation in the foothills west of Boulder, CO.  Tree diameter of around 12" at 6 feet above the ground.  Trees around this size are maybe150 years old or older.  I find them on the largest, lower sections of the trunk, but they might be elsewhere too I don't know.  They seem to be rather common.   I don't believe there is any association with branches, they can be in close proximity to one another but are usually solitary.  The "structures" are about 1" and more in diameter. Sometimes they are "messy" i.e., just a random assortment of the grass-like material that otherwise forms the circle.  In one case I found white "grub-like" bodies about 1 mm in diameter and 2 mm in length around the structure.  There may be a borehole where they entered and there is always some "sawdust."  Could the circular grass-like material be their excrement?   The reason I find these is because when I split old wood the bark will sometimes peel off.  If you were shaving the bark off the tree they would probably be destroyed.   I have some good photos that may help with identification.  Is there an e-mail address or text for phone that I could send them to?   Thanks for your help, Tedd Beegle<personal data hidden>.      -----Original Message-----From: Ask Extension <<personal data hidden>>Sent: Apr 17, 2023 11:29 AMTo: teddngwen <<personal data hidden>>Subject: Re: Identify Insect (#0095718)

responder: An Ask Extension Expert Replied April 19, 2023, 7:42 PM EDT
response: Hello Ted,  Thank you for writing back to the CSU Extension HelpDesk with the additional information. You can send photos attached to your response to the question you sent via "Ask Extension." It's hard for me to tell what the insects might be from the photo already attached.  I've included the link to CSU Extension Fact Sheet 5.528 (Mountain Pine Beetle or MPB). These beetles are frequent attackers of many types of mines, but in particularly ponderosa, lodgepole, Scotch and limber pine. Bristlecone and pinyon are less commonly attached. The fact sheet includes information about the signs and symptoms of MPB attack, its life history and habits, infested trees, control and prevention. It also includes pictures of the MPB.  https://extension.colostate.edu/topic-areas/insects/mountain-pine-beetle-5-528/  If the photos you see in this fact sheet aren't the same as the ones you see with your ponderosa pine, please do send photos by attaching them to your response to my answer.  Best,  Colorado Master Gardener CSU Extension Boulder County