Bugs?

[Paul M. Kaplowitz]

I recently rough-turned some maple bowls and within a few days noticed tiny columns of sawdust sticking out of the sides. I brushed them off and they return. Do I have powder post beetles or some other pest and if so what do I do? Help!! Thanks, pmk

 

[john lucas]

I'm told if you put them in a bag with Moth balls it will kill them. I had asked that question here for a friend who had a finished bowl that he didn't want to mess up with nasty chemicals. He said it worked.

 

[hockenbery]

Sounds like post beetle.

Freezing is often effective since the little critter don't have time to winterize.
stick the piece in the freezer for 2 days.

happy turning
Al

 

[Rob Wallace]

Hi Paul:

To my knowledge "moth balls" (napthalene or paradichlorobenzene) are effective against insect larvae, although I am not sure how susceptible beetle larvae are, relative to moth larvae - particularly if they are embedded in the wood. As long as the concentration of the vaporized material is high enough, moth balls may work as John suggests.

Alternatively, you can soak the item in denatured alcohol, which will kill most things on and in it. This includes not only insects, but fungi as well (which effectively stops the spalting process if you are concerned with this). Even if "alcohol soaking" may or may not work to speed-up the drying process as is claimed, one of the positives about it is the ability to stop insect or fungal degradation of the wood. I can attest to that - I have used it to kill-off wood-borers and to stop spalting, and know that it does work in this capacity. Even though I think the jury is still out on "alcohol soaking's" effectiveness as a drying method due to the lack of controlled experiments and data on use of the method, I still soak many pieces in alcohol. I figure it can't really hurt, has the "killing" effect described above, and may help to even-out moisture throughout the piece to promote more even drying (at least in concept).

I have also heard of people attempting to drip-in or inject pesticide solutions into the wood through the borer tunnels, but this may discolor the wood or may result in having persistent toxins in it, is time consuming and may still not be completely effective. I'm fairly sure I would not advise going down that path.

Lastly, you could try microwaving the piece - carefully - until the wood warms appreciably, if it is small enough to get into the microwave oven. On the assumption that the higher water content of the living insects (compared to the wood), they will heat more rapidly and thus result in an effective "kill". This might be a way to rid your rough-turned bowls of living insects, but the down side is that the wood may undergo cracking or other surface checking, which would be far worse than a minor infestation.

I'd suggest that you try the alcohol method first, since I do know that it works.

Good luck!

Rob Wallace

 

[Rick M]

Like Al suggested, a few months ago I eliminated a similar problem by sticking them into a plastic bag and freezing some newly purchased blanks for a day or two. I had seen other recommendations, but freezing seemed like the optimum thing to try first--IOW, it was simple, fast, and cheap . I figured freezing posed little-to-no risk of alteration or damage to the wood, so I could still try other methods afterward, which I'm happy to report wasn't necessary.

The one thing I'd add to this method is a suggestion to thaw the wood where moisture won't condense on the cold surfaces (DAMHIKT). For me, that meant several hours or overnight separated at least an inch from each other, covered in shavings, down inside a bag (woven material or brown paper).

 

[MichaelMouse]

I know that temperatures of -30F won't kill them, but puts them in suspended animation. Maybe those southern types are more fragile. I'd doubt it. Gets pretty cold in parts of Canada! http://www.pestcontrolcanada.com/powder_post_beetles.htm

It's easy, given the length of the life cycle, to claim the critters are gone, even when they aren't. We see the frass from the larva, and the occasional beetle before it uses its new mobility to depart and infest other places. We don't normally follow either.

As to the vapor pressure of alcohol versus moth balls, no contest. Moth balls very high. Though the molecular size is large, I'm going to say that they will still diffuse through the wood faster, and with a pretty good LD50, kill effectively. I'll discount the diffusion of the liquid EtOH state heavily, having performed controlled experiments with the stuff showing that the rate of penetration in wet wood is extremely slow. FWIW, the result of those experiments show that distortion and dry rate between identical samples of the four woods selected were identical. Others who have done side-by side comparisons confirm that the laws of Physical Chemistry have not been repealed in favor of turners.

They're sort of related, so if you're curious, one place to look is http://www.chemguide.co.uk/physmenu.html#top

 

[Mark Wollschlager]

In addition to the above methods.
I have heard that sealing the wood in a bag with several pieces of dry ice will kill the bugs..
Leave the bag sealed for a couple of weeks.

Mark.

 

[Dick Hines]

If you see the holes drip some thin CA in the holes and put a piece of paper tape over the hole. If the CA doesn't get them the fumes will.

 

[Carole Valentine]

Don't know how many you have in the wood, but with those grubs that get in cherry, when I can see the openings to the tunnels, I use a hypodermic needle to squirt a little DNA in the holes. The grubs back right out in a hurry.

 

[john lucas]

Carole do they stagger and have party hats on when they come out.

 

[Robbie Graham]

I've had the same problem over the years and found microwaving the piece for a short time work well. You don't need to get the piece very hot as the moisture in the grubs gets hot first and kills them pretty quick.
Robbie

 

[Gary Slater]

freezing?

If the wood is still wet, wouldn't freezing promote cracking since water expands when it freezes? I would therefore be reluctant to try freezing.

 

[MichaelMouse]

If the wood is still wet, wouldn't freezing promote cracking since water expands when it freezes? I would therefore be reluctant to try freezing.

Flexible cellulose walls and air spaces will easily accommodate a 9% expansion. No worries.

 

[Rick M]

If the wood is still wet, wouldn't freezing promote cracking since water expands when it freezes?. . .

In my case, no. Many types of wood undergo below-freezing temps for extended periods of time while the tree is still alive and recover just fine when the temperature rises. While alive, although probably dormant, IMO the moisture content is likely higher even then as compared to the blanks I needed to treat.

Compared to seasonal changes in temperature, I believe it's the relatively rapid change from one extreme to another that kills the invaders before they can acclimate themselves, unlike the normal processes in Nature.

 

[Joe Greiner]

A few years ago, I felled an oak tree in my back yard, and cut the log into planks for a non-turning project. There seemed to be some critters present. I'd read someplace that termites can hold their breath for 15 minutes. I stapled some kraft paper bags into a tube, placed the planks inside, and tied the open end to my truck's exhaust. I let the engine idle for about an hour.

As the routing project progressed, I picked the dead critters from their galleries. Eventually, I packed the galleries with Bondo auto body putty (mostly on the back of the workpiece).

My meager knowledge of bio-chemistry indicates that carbon dioxide (e.g. from dry ice) kills by displacing oxygen. Carbon monoxide (car exhaust) kills directly. A stockpile tent with CO from a lawn mower engine exhaust would be more efficient. It had no effect on the wood as far as I can tell.

 

[MichaelMouse]

In us critters, CO occupies the space on the hemoglobin that O2 would occupy. Asphyxia kills. CO2 kills by acidosis, a direct method.

Insects have no hemoglobin to take up the CO, so I rather suspect it was deprivation of O2 which caused the death.