Bugs in my ash lumber ???

[Karl Andersson]

Judging from the size of the big holes and the fact that it is dry wood, it is more likely powder post beetle or "old house" beetle larvae. The big round holes mean the adults have already left, the small holes look more like some planing or wear on the benchtop has exposed the "high points" of a larva tunnel - but the larva could still be alive, so a boric acid solution applied in these holes would be worthwhile. You may want to swab the surface of the bench with the solution also - the exiting adults may have mated and laid eggs back on the surface. Doubtful unless you have a lot of the larger holes, but just to be on the safe side, it could penetrate enough to stop newly-hatched larvae.

The ash borers are more of a threat to live ash trees - the restrictions on firewood are to try to slow their migration. The larvae live in the bark and sapwood where it is moist enough for them to live - they shouldn't be a problem in dried heartwood.

There are some State recommendations that suggest using a tight tarp in sunlight to achieve the required 160 degrees for several hours needed to kill the borers. I know I killed a large section of lawn by laying black neoprene pond liner on it in bright sunlight (oops) and the neoprene was too hot to handle - maybe you could get some heavy black plastic from a landscape supplier and move the bench into the sun and wrap it up with an accurate oven termometer; kind of a solar kiln.

By the way folks, don't kill the beatles....they're old and there's only two left...and they've both been knighted...

[Ron Conlon]

Sounds like you got a bug up your ash.

This will only confirm that I have a juvenile sense of humor, but this cracked me up!

[Steve Branam]

You can also do the same with chlorox, but the same precautions apply. A snootful of fumes from a concentrated chlorix solution will be just as damaging as a snootful of ammonia vapors.

And as long as we're talking about these chemicals, absolutely DO NOT mix them. I don't know the precise chemical reactions, but chlorine bleach mixed with ammonia (either plain old household strength or more powerful industrial strength) produces toxic chloramine gas. Bleach mixed with acids releases chlorine gas. You may remember these as some of the gases used in chemical warfare during World War I.

Here's a fact sheet on the dangers of mixing household cleaning chemicals: http://www.state.nj.us/health/eoh/cehsweb/bleach_fs.pdf

[ray hampton]

the ammonia do not had to be full strength, using Clorox water to clean up after pets will form the gas because some pets urine contain ammonia

[Bob Jones]

I closely inspected the whole bench and I only found the holes on a few spots on the top of the bench. I decided to mark the holes that i see and pour a bit of clorox on those spots. I will see if more holes develop. I think it is strange that I only see the holes on the top. I would seem to me that if the lumber were infected there would be holes in more locations. Thanks for the advice!

[Paul Bombardt]

Bob,
You have powder post beetles in your ash. The easiest solution is to coat around the holes and as much of the wood with a product called Boracare. It is a boric acid product used to kill powderpost beetles. Look it up on line, I got mine from a place called Do it yourself pest care. They have loads of info about these critters. They can emerge years after boring and are indeed usually killed by kiln drying, so you may have an infestation that started after the lumber was dried. Other writers are correct, they mostly infest hardwoods, pine seems immune. I have lots of problems with them, mostly in maple and ash and a little in oak. Walnut and cherry seem to resist them more. Polyurethane doesn't seem to stop them. As I understand it, if the hole looks hollow, that is no sawdust in it, that is where they have emerged. If the hole looks like it is filled with powdery sawdust, then they are probably still in the cavity. The eggs are miniscule and I have never seen them. The beetles themselves are only about 1 mm in diameter (the biggest ones) and about 2-3 mm long. I have an old barn that I treated multiple times, and when the beetles emerge, they eat the wood that has been treated, and then die, you'll see them lying around. This goes on for years.

Good luck.

[Scott T Smith]

I closely inspected the whole bench and I only found the holes on a few spots on the top of the bench. I decided to mark the holes that i see and pour a bit of clorox on those spots. I will see if more holes develop. I think it is strange that I only see the holes on the top. I would seem to me that if the lumber were infected there would be holes in more locations. Thanks for the advice!

Those are powder post beetle holes, and you typically find them near the surface of the log. I'll bet that your bench top is "bark side up", which is why the holes are predominantly visible there.

David Keller NC's advice about ammonia fuming is rock solid. I followed his advice to fume a 14" thick, 48" wide oak slab last year, and it worked great. I did fume it for a couple of weeks though, in order to allow the fumes to penetrate as deeply as possible into the wood.

Regarding heating the bench to sterilize it, the comments regarding 160F being required are not correct. You need to heat the core of the bench it to 135F for 4 hours (USDA Forestry Service recommendations). You can do this by building a box out of insulation around the bench, and placing a space heater underneath it. You will want to put a vent in the top so as to control the level of heat. I believe that the December 2010 issue of FWW had some recommendations on sterilizing lumber at home by a similar system.

I have also used the boric acid solutions on large timbers, but only on green lumber. Of all of the methods suggested, IMO the ammonia fuming option will do the least amount of damage to the bench.

All reputable kiln operators run a sterilization cycle at the end of the kiln run - including operators of dehumidification kilns. Either this step was skipped, or the wood became infected after it was kiln dried.

[Bart Nadeau]

I hope Bob will keep us up to date on his bench problem. Also, wonder if he ever discussed with his lumber supplier and what the outcome of that was.

[Matt Uchida]

So using ammonia on a finished piece might mess with the finish? Do you know what types of finish it would mess with or might it mess with all types? I often use a danish oil and top with wipe on poly. I ask because a small end table I made for a relative has some sort of bug in it making a mess.

[Scott T Smith]

So using ammonia on a finished piece might mess with the finish? Do you know what types of finish it would mess with or might it mess with all types? I often use a danish oil and top with wipe on poly. I ask because a small end table I made for a relative has some sort of bug in it making a mess.

Matt, a superior solution to ammonia is to sterilize the lumber with heat. The core of the boards needs to reach 133F for at least 30 minutes. With a small piece such as an end table you can build an open bottomed box out of foil faced foam board, set it and the end table on top of some sawhorses and place a small space heater underneath it.

I have some drawings of this system that were published in FWW magazine a few years back. If you PM me your e-mail address I will be happy to send you a soft copy.

[Kevin Gade]

My understanding is the ash borer live in the bark, not the heartwood. That would eliminate the borer as you problem.

[Matt Uchida]

Matt, a superior solution to ammonia is to sterilize the lumber with heat. The core of the boards needs to reach 133F for at least 30 minutes. With a small piece such as an end table you can build an open bottomed box out of foil faced foam board, set it and the end table on top of some sawhorses and place a small space heater underneath it.

I have some drawings of this system that were published in FWW magazine a few years back. If you PM me your e-mail address I will be happy to send you a soft copy.

Would the heat affect any finishes already applied? I would have to buy a space heater because here in Hawaii we have no use for such things!

[Chris Hachet]

Would the heat affect any finishes already applied? I would have to buy a space heater because here in Hawaii we have no use for such things!

Not sure if it would affect the finish....but heat seems like a simple straight forward answer. I ahve used it in the ast on both antique furniture that has become infested and air dried lumber with good effect. Of course, i also dumped lacquer thinner down any holes and on any infested areas.

[Allan Speers]

This thread is still going? Holy cow.


Just spray some Bora-care on the thing and be done with it. It will soak through most finishes and will kill anything still in there.

[Chris Hachet]

This thread is still going? Holy cow.


Just spray some Bora-care on the thing and be done with it. It will soak through most finishes and will kill anything still in there.

Good to know, as I am looking to build some more stuff with re claimed wood that has been in a barn for awhile.