What bug is this in my wood?

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Forum topic by Elizabeth posted 07-20-2013 07:21 PM 2579 views 0 times favorited 21 replies Add to Favorites Watch
View Elizabeth's profile


823 posts in 4602 days

07-20-2013 07:21 PM

I just got out to the shop for the first time in at least a month. I have some housekeeping projects to do, so one of the first things I did was pick up a dry chunk of log that has been sitting near the garage door for, oh, over a year, with the intent of moving it farther into the shop. It had been standing on its end.

I picked it up, and noticed a pile of sawdust around the edges of it. ...That can’t be good.

I pulled it out into the driveway, and saw some of the bark was loosened. I chopped it away and found some little white grub-like things, at least four of them in the pieces I removed, eating holes along where the bark and wood meet. Here’s my quick attempt at some pictures:

Live grub on left, squished one on right

Trail on the inside of a piece of bark:

Pulled up another piece of loose bark and found this guy at the top:

What are these?

There were other logs stored near this one, but not touching it. None of the nearby logs are showing sawdust signs, as far as I can tell. I don’t remember how long ago I got this particular piece but I’d guess over two years and it has been air drying since. I probably got it with others. The others are in various spots around the shop. This piece wasn’t always here. It used to be in the back for a while. In its current location, if a bug were to come through the edge of the garage door it would encounter this piece of wood first.

Most of my cut lumber is stored on wall racks. Only the logs are stored on the floor.

How screwed am I?

Secondary question, if I completely debark this piece and get rid of all the grubs, is it okay to keep, or should I just chuck it into the yard waste bin right now?

21 replies so far

View lew's profile


13534 posts in 5214 days

#1 posted 07-20-2013 07:30 PM

Not sure but might be a powder beetle grub
Check here-

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Elizabeth's profile


823 posts in 4602 days

#2 posted 07-20-2013 07:37 PM

Hm. That piece is going in the waste bin now. It’s nothing special and I don’t want this to spread.

View coachmancuso's profile


259 posts in 3390 days

#3 posted 07-20-2013 07:54 PM

You can put it in a black bag tie it tight and leave it in the sun for a couple days

-- Coach Mancuso

View Elizabeth's profile


823 posts in 4602 days

#4 posted 07-20-2013 07:56 PM

Will that work? I thought only kiln drying would kill them.

I checked some other pieces that looked the same (Apparently I didn’t treat the ends of this batch) and found one more piece with bored exit holes and another piece with at least one grub. All next to each other.

Also checked a piece of Sweetgum lying nearby, with anchorseal on the ends. ...No, that one is just going moldy underneath the bark. FFS.

View zwwizard's profile


215 posts in 5168 days

#5 posted 07-20-2013 10:24 PM

Looks like you have a piece of walnut there. Strip the bark off and just scrap the log off, You should get all the grubs off that way, they just work under the bark.
Power post beetles are tiny little things that like the sap wood mostly.

-- Richard

View David Coburn's profile

David Coburn

24 posts in 4150 days

#6 posted 07-20-2013 10:30 PM

Yea, I agree.. I don’t think that is a powder post beetle. The dust is like talc not at all what your pictures look like.. and like zwwizard said, they are tiny… that grub is way too big.

-- david

View Blackie_'s profile


4883 posts in 3972 days

#7 posted 07-20-2013 10:55 PM

It is a beetle larvae, one of many species it looks real close to the longhorn beetle larvae and yes they tunnel through wood, Elizabeth if it can fit into a microwave that will also kill them anything with heat such as your oven for a short bit but not to long, the loose wood that the beetles cause can add character to the wood and you can harden it up by dripping super glue on it, the super glue finishes great it never leaves any sign.

-- Randy - If I'm not on LJ's then I'm making Saw Dust. Please feel free to visit my store location at

View bondogaposis's profile (online now)


6183 posts in 3810 days

#8 posted 07-20-2013 11:34 PM

They look like roundhead borers otherwise known as longhorn beetle. I’m pretty sure once you strip the bark they will be gone. Because it was standing on end it allowed the wood to wick moisture up into it. Those beetles work on the moist sapwood just under the bark. Once the bark is gone it will be too dry for them.

-- Bondo Gaposis

View David Dean's profile

David Dean

608 posts in 4358 days

#9 posted 07-20-2013 11:42 PM

hey guys down here in missouri we got like 6 countys that cant sale fire wood becouse of some Green bug that is eating ash and sawmills cant cut or sale any ash etherso you my what to look around its about a 1” long and green.

View spunwood's profile


1202 posts in 4295 days

#10 posted 07-21-2013 12:49 AM

I don’t know but I think I see one coming out of my nose!

-- I came, I was conquered, I was born again. ἵνα ὦσιν ἓν

View crank49's profile


4032 posts in 4430 days

#11 posted 07-21-2013 02:21 AM

I thing I read somewhere that 140 degrees F would kill bugs in lumber.
Due to the mass of those logs it might take a few days to soak the heat through from sitting in the sun, but I suspect it would work.

View jumbojack's profile


1691 posts in 4083 days

#12 posted 07-21-2013 01:26 PM

The black plastic bag method, with bark stripping will do the trick. Im in California and I see this in wood piles all the time. Ive only seen them on wood with bark intact.

-- Made in America, with American made tools....Shopsmith

View Blackie_'s profile


4883 posts in 3972 days

#13 posted 07-21-2013 06:55 PM

Nice to know Michael.

-- Randy - If I'm not on LJ's then I'm making Saw Dust. Please feel free to visit my store location at

View MT_Stringer's profile


3183 posts in 4690 days

#14 posted 07-21-2013 07:06 PM

You could put it on the dash of your car. 140 deg is easily obtainable when it is sitting out in the hot sun. I measured several places inside my truck once years ago when I was at work and had access to a high temp digital thermometer (used to measure tube temps in furnaces).

Actually, I am just kidding about putting it in your car but serious about the temps. The glass window adjacent to where my head normally would be when driving was 131 deg F. The console was about the same. The dash was 141. It was 98 outside.

-- Handcrafted by Mike Henderson - Channelview, Texas

View Elizabeth's profile


823 posts in 4602 days

#15 posted 07-22-2013 04:47 PM

Thanks guys. Feeling a bit better about all this now. I’ve pulled out the afflicted logs – since I hadn’t sealed the ends they all cracked heavily anyway, so I decided to ditch them. Not seeing any loose bark on any pieces that had had sealed ends, but I’ll keep an eye on them, and I have taken a bunch of air dried western red cedar boards (a couple of them showed similar trails) and black-bagged them in the driveway on Saturday. One of the bags appears to be melting so I guess they’re getting pretty hot!

I also found this little guy in my shop, chilling out behind a piece of plywood that my bandsaw came in a few months back. He doesn’t appear to be either a powder post or an asian longhorn beetle; not sure who he is. Forefinger for scale.

He was somewhere else in the shop entirely so I am hoping he’s not a troublemaker.

I’m spending as much time as possible over the next few days cutting up the remaining sweetgum. I got through two pieces yesterday. Fun side note; yes they were starting to get a bit moldy, but some pieces have also got some interesting spalting from it. So I guess there’s that. I haven’t been running my dehumidifier because it appears to have broken. I guess that is why they started to mold.

showing 1 through 15 of 21 replies

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