Bugs in Osage Orange

A bowmaker troubleshoots tiny bug holes in his stock of Osage Orange. January 8, 2010

I have some osage orange that has clearly been infected with some bugs. I don't know what kind though. This surprises me as I have never had bugs get in my osage before. I cut and use a lot for bow staves. I have actually even heard people say that bugs can't even get to the stuff on account of its hardness.

So what are these bugs? They have fairly small holes, a little bigger than the point of a ballpoint pen. They got in mainly on portions where I didn't get the bark stripped off (I was in no hurry, as I have never had this problem before). Most of their holes are in the sapwood, but a few go quite deep into the heartwood, some maybe an inch or so. They also seem to have stopped now that the wood has sat around for about two years.

Forum Responses
(Sawing and Drying Forum)
From contributor D:
If I remember correctly Gene has mentioned a certain type of beetle that leaves holes similar to a Powder Post Beetle (around the size you mentioned) but that prefers wetter wood (I can't recall the name right off). I know PPB's prefer dryer wood, so I doubt it would be them.

I have heard of other bowyers having what they call grubs (supposedly some kind of wasp larvae) to infest their osage while it’s drying. Typically they eat the sapwood and only go a couple of growth rings into the heartwood (which sucks for bowmaking of course), but I don't know of the size hole they leave. Have you seen any of the bugs?

From the original questioner:
All I ever saw was some larva of something else just under the bark, but those were too big to leave these holes. I think they were just eating the bark. The tiny holes were accompanied by piles of very fine yellow dust (osage is bright yellow fresh). I admit my error on this. I didn't get the wood taken care of in time -it sat out for too long. I try to get the wood inside right away usually, and that may be why I have never had this problem before.

I would still like to know just what these guys are though. Fortunately the trees I have are large enough that I can cut down far enough to avoid the holes and the wood is useful yet for bows. I was very worried at the first, because this tree is undoubtedly the best osage I have ever seen, three 8-10 foot sections of clear log on the trunk! That never happens – you’re lucky to get one section completely clear and rarely get two, at least around here.

From contributor D:
I'm jealous. At least you have osage up there! Down here in ‘Bama they're few and far between. I do have one nice osage stave I cut two years ago that I'm looking forward to using when I get time. We do have plenty of hickory, though. Glad to hear the damage is not too deep.

From contributor S:
It could be Flat head Borers (Buprestidae), also known as metallic wood borers. Or it could be Bark Beetles (Scolytidae), also known as shot hole borers. Both of these bugs get into the sapwood and lay eggs. I think the Bark Beetles would be a more likely situation in that their tunnels when they emerge looks like small shot holes.

From Gene Wengert, forum technical advisor:
Another beetle is the ambrosia beetles. Also, anobiid beetles.

From contributor W:
Until recently we had little experience with osage orange (Bois d'Arc). We are in central Texas and do not have a lot available. Late last year we got a fair sized tree which was milled and then a couple months ago we got a utility trailer full from close to a neighboring town, so I can say we have had experience with both wet wood and dry wood. The first was milled in cool weather so borers didn't have a shot at it. The sap wood in the dry wood is riddled with powder post and the logs we haven't had a chance to mill are full of the painted hickory borer.

So ID'd by a pHD in entomology - I first thought it was the Locust Borer and then we both thought it was the Mesquite Borer but microscopy and autopsy of the critter says it's Painted Hickory Borer (all three species look identical to the naked eye). It's the same bugs as get in the mesquite here and if it's possible the bois d'arc has a heavier infestation than mesquite. You can stand eight feet away from the logs and it sounds like a bowl of Rice Krispies with hundreds of little mounds of dust on the ground.