Not Asian Ambrosia Beetles Identification

Q: Our 20-plus year-old Japanese Maple has shown signs of Asian ambrosia beetle infestation since last year. On inspection, I removed sawdust and decayed wood and found white, living insects inside the trunk, along with occasional small black/brown beetles. I have not observed the characteristic “toothpick” frass typically associated with the Asian ambrosia beetle. 

A: You don’t see Asian ambrosia beetles because you’re looking at a different boring beetle. According to the pictures you sent, they are working in a wound in the tree trunk. Different beetles specialize in the damage they do to unprotected wood. I suspect these are another kind of ambrosia beetle that bores deeply in sapwood and kicks out lots of sawdust. These beetles can be controlled by soaking the wood where you see the holes with insecticide. This has to be done at least twice a year. The reason your Japanese maple has continued to thrive is that there is still some unharmed bark next to the wound. Moisture and nutrients travel under healthy bark.