Identification based on images in this section of the Guide.

This is image 1 of 4.

Image 1 shows a living individual as it moves about on the trunk of a young sassafras tree, and a bored hole to the lower right. Images 2, 3, and 4 show views from different angles of an individual from the same tree where the living individual in image 1 was found.

On August 29, I noticed that a young, 10 to 12 foot tall sassafras tree in my back yard had suddenly wilted even though we have had a season with plenty of rain. It was the fourth and largest sassafras tree in my yard to wilt within a couple of months. I went online looking for information on dying sassafras trees, and was quickly provided with links to information on Laurel Wilt disease and the involved bark beetle, Xyleborus glabratus. Armed with that information, I went out to the tree with a hand lens and camera. I found several small, round holes in the trunk. Most appeared to be occupied. Eventually I noticed a single individual crawling around on the trunk. Unfortunately, it was after 7:00 PM, it was a moving target, lighting was poor, and I had to use the flash which is tricky in macro mode with my camera. I got enough images that were good enough for me to rule out Xyleborus glabratus, but not good enough for me to make a good, but inexperienced, attempt at identification.

Since the sassafras tree was doomed anyway, I decided to cut the trunk into short sections that I would put into a jar and wait for individuals in the occupied holes to emerge. When I first started cutting the sections it appeared that holes that had been occupied were vacant after the cut, but after a while the holes would appear occupied again. I took a thin piece of straw and gently tapped on an individual in one of the holes and watched it disappear deeper into the hole. After a short period, maybe less than a minute, it slowly moved back up to the surface, rotating back and forth through a small angle as it went. I put several short sections of the tree trunk with occupied holes in a jar. On September 1 a single individual appeared moving around in the jar, but soon died. I poured it out of the jar and took pictures and measured its length to help make an identification.

As I write this it is now September 5. I have not seen any other individuals in the jar moving around, but two or three previously occupied holes now appear empty, and new holes have been bored and sawdust piles have appeared in other places. I don’t know when the beetles are normally active. I check the jar frequently, and keep the jar in the bathroom overnight for convenient overnight checks.