Borer treatment

[JoshNZ]

What do you guys do to a pile of green lumber fill of borer flight holes? Still live borer in them as I've seen dust pushed out of the holes after milling. It is about 25 ~3meter lengths of an NZ native I chainsaw milled last week.

[GeneWengert-WoodDoc]

In the states we need to know the MC and the diameter of the hole in order to give precise advice.  Also, hardwood or softwood.

[JoshNZ]

I'm not sure how precise of a diameter you need, it fits a 2mm drill bit snugly, but not a 2.5mm bit, how's that?

MC? Can't for the life of me find what that would mean on google sorry.

As to the hardness, I'm not certain. It is an evergreen angiosperm so I guess you'd call it a softish hardwood, reasonably easy to cut. I've never dealt with it in its dry form so I'm yet to learn.

I have seen treatments in the hardware store that claim to be effect against all forms of borer in NZ, maybe this means that everything we have here can be killed by the same chemical? Product aside, what is the practical method of treating a stack of lumber? Some boards are clear of holes, some are peppered.

[farmfromkansas]

A neighbor cuts ash for firewood.  He said he sprays a household bug spray on the ends of the logs and it gets rid of the borers.  This forum does not like bug killer. I used some malathion once on ash logs, as it is just full of borers here in Kansas.

[Don P]

Josh, what was the hardware store treatment?

[JoshNZ]

I can't remember where I found the exact quote "kills all species of borer" now. This seems to be the most common one and does mention in the PDF provided that it kills all wood damaging insects.

https://www.kiwicare.co.nz/products/pest/borer/

Obviously it is not going to be practical for me to inject all flight holes with a product so I guess I am looking at one of the sprays. I'm just wondering if a spray is going to do it, on the ends, or all over, or if I'm going to have to hang a plastic room around it and fumigate or what.

I've also heard spraying a bit of jet-A or kerosene around can do the trick... Must be a myth surely?

[GeneWengert-WoodDoc]

MC = MOISTURE CONTENT

Hardwood = leaf tree
Softwood = needle tree

Did you notice a small dark ring around many of the holes?  If so, then ambrosia beetle, which is one type of powderpost beetles that likes wetter wood.  They are not active in dry wood.  It is hard to identify insects without actually seeing them.  Plus, you might have different insects than we have in North America.

At this point, you have an active infestation, so any insecticide would have to go inside the wood totally and not just a thin layer on the outside. There can be many larvae in the wood that are making tunnels but have not yet left.  Fumigation is the only effective choice therefore.  Of course, the insects that have left the wood are looking for a new home, so uninflected wood could actually be infected, but the insects have not developed enough to make the exit holes.

Some Borate compounds are effective as they migrate into the wood if the wood is soaking wet or the wood is soaked or submerged in the borate solution.  The soaked wood is removed from the tank and then tightly covered with plastic. After some weeks, maybe 4 to 6 weeks of warm weather, the wood will be treated throughout so that both present and future protection is provided.  The past damage still exists, which can mean low strength of the wood.  Borates can be sprayed or briefly wet the wood to give a poisoned outer layer; this is ok if the wood has no existing infestation, but soaking is needed when attacking an exiting infestation.

With all insecticides and home remedies, remember that these chemicals are in the wood, so the wood dust, planer shaving and the wood itself in the final product have these chemicals.  Some chemicals are not healthy to breath, chew, touch, etc.  Always use approved chemicals.  In the States, we also,need to tell the buyer of such treated wood that it has these chemicals within the wood.  The buyer would not want to breath sanding dust, make a toy or crib that a child would chew, make a cutting board for food preparation, etc.  For this reason, approved insecticides used at the sawmill are very short lived, so they will be essentially gone when the lumber is sold.

Note that another control option, and maybe the least expensive, is to heat the wood throughout to over 133F or 51 C.  This is widely used in the states in order to assure the export markets that the wood is free of insects and fungi.

[Don P]

Note that another controller option is to heat the wood throughout to over 133F or 51 C.

There's the real solution, preferably in the midst of an open bonfire. I thought of a borate bath too but why. When you hit that, get it off the mill and into the burn pile. Now you are just throwing good money after bad. I tossed some nice curly white oak on the pile yesterday. Not good but better than incorporating into something and having problems "surface" later.

[longtime lurker]

Borer control is pretty easy if you start right. Somewhat more difficult as a remedial treatment after the baords are sawn because you need to rehandle them.

Effective borer control starts at the stump. Fell the tree, then try and leave the bark intact as much as possible through the extraction process. Seal log ends promptly to retain moisture in the stem... what you're doing here is trying to hold the living trees borer protection system intact until you get it to the mill.

In the mill yard you can either keep logs wet by ponding or with sprays which will keep the MC high enough to keep the borers out.  And the mill yard itself needs to be borer unfriendly: as with termites you want to keep the yard free of things that can sustain a life cycle.
Or keep the borers out with chemicals. Diesel is a great chemical for overspraying log piles for borer protection, kero is another. Most agricultural type insecticides - diazinon, tokuthion,malathion, lorsban, etc will work (if it kills termites it'll kill borer) Best of them all is a specialist log and lumber treatment such as Pounce 500, which has a fair bit of "stick" for keeping rain from washing it off.

http://pcti.com.au/Product-Range/Insect-Control/Liquids/Pounce-500.aspx
Most rural supply type places will be able to get you Pounce.

After sawing its borax time. You want 60% borax (disodium octoborate) mixed with 40% Boric Acid. (again rural supply places will be able to get this) by weight. Dissolve that in water until you cant dissolve anymore in. Then you can spray that onto your freshly sawn timber or put it in a trough and dip your boards in. Stack as per normal. This is NOT borate treatment of timber which involves diffusion, this is just a quick surface treatment to kill whats down any holes and give a surface barrier to future infestation. It will hold so long as the timber doesn't get wet at some point to wash it off.

if you intend to store the timber weather exposed and want enduring insect protection then you need to get serious about it. Theres a few options, some suitable for backyard type operations...I'll cover them if required.

Remedial treatment of borers you get to either unstack the timber and drown in borate solution as above, and in this case a trough is the only sensible way to do it because you want to drown the buggers down the holes. Or you can put your pack of timber in a sealed environment such as a container, or even under a heavy plastic sheet, and let a couple household bug bombs off in there and choke them to death instead.

Heat treatment has been covered but it only kills whats there. Next week their cousin brothers can move in.
Kiln drying also works but if the timber gets wet again it is still open to attack once the noisture level rises.

KNowing what species of borer you have can help. try here:
http://www.nzffa.org.nz/farm-forestry-model/the-essentials/forest-health-pests-and-diseases/Pests-of-timber

[GeneWengert-WoodDoc]

A comment about dip treatment.  With very small holes, it is difficult to get water to go into the holes due to surface tension of the water and the air that is in the holes.  However, in the States, the insect we call a borer makes holes at least 8 mm.  The ambrosia beetle and similar holes (2 mm) are only in sapwood and require some drying before they get into wood.

Also, remember, as you stated, that the NEW holes in lumber are exit holes.  Of course, when sawing, you can saw into and see holes or tunnels that are inside the wood and insects that are not ready to exit the wood.  So treating NEW holes is like closing the gate after the cows are already out.  We also have to consider all the holes or tunnels that have active larva that our sawing did not expose.  A dip treatment will not initially get into those holes.

So, for fresh wood that has not dried, chemical treatments are best considered as creating a barrier to prevent any new insect infestation from entering the wood. 

Existing infestations are harden to kill thoroughly in freshly sawn lumber, with heat often being the most practical control.  (As an example, wood pallets and dunage for shipping overseas from the USA, and logs and some lumber all require treatment, which is nearly 100% a heat treatment.  Heat is easy and not expensive.)  Borates are also possible, but usually they require dipping and then covering the treated wood pile with plastic to avoid drying and rain, and to allow diffusion to ossuary over a few weeks before beginning drying.

As drying proceeds, then fumigation ($) becomes viable, but most fumigation chemicals are quite dangerous so you cannot do it yourself.

[JoshNZ]

Hey thanks for all the replies guys sorry about my absence. I think I will go with the boric acid + borax spray solution, it is the only one really viable to me as I don't have access to a kiln or a way to keep heat around the boards, don't want to mess with baths etc.

I'm happy with preventing further infestation, rather than killing what is in there. The boards with flight holes already have flight holes and a few more won't change what I'm able to do with them, some may well end up on the rubbish pile. The boards without flight holes seem to be from the lower end of the tree and it would be nice to keep them borer free if I could. So a good soak down of the lot in acid+borax should offer some protection?

Does this leave the wood food safe? I.e. if I ended up turning bowls or making chopping boards etc.

[JoshNZ]

And while I'm on the subject... 10L of solution would be enough to wet down 30-40 3M lengths? I have another tree with no borer in it at all that I'm getting through so the stack has gotten a we bit bigger.

So for 10L of solution how many kg of acid/borax do I need to achieve full saturation in water?

[Don P]

Mixing boric acid and borax and heating produces DOT, can you simply get DOT locally? Here it goes by Timbor, Solubor, Beau-Ron. I mix at 1 lb/gallon of water for a "regular" 10% solution or 1.5 lb/gal for a short lived 15% solution (crystallizes pretty quickly). If not I'll try to dig up the mix instructions for the borax/acid mix.
No it is not food safe, look up the msds on timbor.

Edit;
"Based on U.S. Navy specs, a ratio of 60% borax and 40% boric acid gives the maximum solubility of borates in water."

edit2 MSDS;
http://nisuscorp.com/images/uploads/documents-specimen-labels/label_sds_timbor.pdf

[JoshNZ]

I can see it available in NZ online not sure where I could go and pick it up. I can pick up the acid and borax I'm sure of that.

I guess as far as food safe woods I just have to keep a bit of it seperate in a food safe pile and keep it away from borer...?

[Don P]

Another reason why I said to burn it. Are you sure you want to risk building a healthy colony of borers to save this marginal wood? I'm telling on one's elf here, I did it. I'm probably going to pull the circle mill, tear down and burn the sawshed, scrape and replace the soil and drop the big one on the site. I use red lumber crayon and put a B on borated boards. DOT is a soil amendment for veggie growers, I buy it at a real farmers supply.

[JoshNZ]

Well how much of it do I burn, anything with a hole in it? All of it? If I burn it all I'm left with no wood at all which doesn't make much sense haha.

I'm just a hobby woodworker. Don't have a mill site or anything, I've pushed a chainsaw bar through 4 logs and will leave it somewhere to dry, simple as that.

[Ianab]

Here in NZ I've noticed 2 different type of borer. There are the ones that attack green wood, and others that attack dry wood, even pine, and less durable natives.

Reason this matters is the "green wood" species aren't a long term problem, as long as you can get the wood dry ASAP. If it's slow drying they can basically "Gut" a board or log before they die off. I had a large slab if Lawsoniana that I had (stickered) in the shed, but it took too long to dry. I've never seen bugs attack dry Lawson before, so I was a bit careless. These bugs basically turned all the sapwood to dust before the wood dried out.

The other (smaller) bugs are the ones that get into old houses and dry wood. A borate dip while the wood is drying should discourage them, but make a note that the wood has been treated. Borate isn't horribly toxic, they let kids play with it in the "slime kits" etc, but it's water soluble and would leave out of the wood.

Personally I like wood that the borers aren't interested in. Lawsoniana, Macrocarpa, heart Rimu etc.

[DMcCoy]

Question for you guys who dip your boards.  What do you use for a tank?  A box lined with plastic sheeting?

[Don P]

I just made sides out of boards with a 1/2" plywood bottom. Generous subfloor glue and lots of nails. A few boards across the bottom and across the seam in the ply then 5 short horses or stacks of blocks to support it level. Then caulk and paint the inside. A 1" hole and plug at one end and drain through window screen into 5 gal buckets when done. I've meant to bend some flashing tin and line it but haven't gotten round tuit. You can't store it in buckets for too long or it settles out into a pancake of solid borate in the bucket. That can be redissolved on a woodstove in the shop but its a pain. I use a heavy knap roller to use that up if I'm done for awhile. A little, very little, dish soap will help break the surface tension and let it wet out the wood better. I have a few brake discs and drums to weight down the boards in the tank. If on the grass I put down a sheet of plastic on the ground. If in the shop or barn I don't mind it hitting the floor.

I understand Josh's feelings about not wanting to lose the effort in those boards, been there many times. My feeling is that when you hit an infested log, stop cutting and burn it before wasting any more time on it. At each stage it moves up the line you become more invested in what is really trash. It's one of those know when to cull things. We all have a different break point there. I'll go to the effort to evict them from a structure where the time and effort to remove and replace is high, that isn't a quick spray but multiple wet on wet glycol mix applications. I'll dip, spray or roll it onto good boards as a deterrent but if a board shows signs early in processing I call it dimensional firewood and cull it instead of investing more time and inputs into it.

[longtime lurker]

I understand Josh's feelings about not wanting to lose the effort in those boards, been there many times. My feeling is that when you hit an infested log, stop cutting and burn it before wasting any more time on it. At each stage it moves up the line you become more invested in what is really trash. It's one of those know when to cull things.

Smartest thing I've read all year. The more you play with it the more it owes you and sometimes the smartest thing to do is just leave the log in the bush beside the stump. A lot dpends on the species of borer... we get a lot of pinhole borer at times... even when its heavily infested prodived you've killed the little beggars its still fine for paint grade material. But there aint a lot of money in paint grade material either - basicly means we're paying hardwood mill costs to get pine money - and all it is is cost recovery on the log.

[JoshNZ]

I do see what you're saying but I really have nothing invested in it other than a few gallons of fuel/oil and a bit of my leisure time. If it's a lost cause in a couple of years I won't be very upset.
The reality is if I destroy it all now all it will mean in 2 years from now is that I'll be sitting on the couch with no timber in my shed.

So is pulling the boards with holes out and spraying down the rest of it with $60 bucks of solution really throwing much away if it doesn't work out? There's plenty I can make while having to cut away infested stuff if it does come to that.

Anyway... I have figured out what the buggers are I think, they look like a powder post beetle. I just looked at the stack today and there's a few lying dead on the boards with holes. Are they dying because it's drying or because that's it for their life cycle?



As you can see it's not a big stack of timber, it won't be much effort to spray it down if it prevents more holes it will be worth it for me.

[GeneWengert-WoodDoc]

If you spray with borates with lots of excess, and the immediately wrap the pile completely with plastic, the excess will slowly move into the lumber and get those inside, if the species is permeable.  After 4 weeks, uncover and stack for normal drying, but keep rain off the lumber.

[JoshNZ]

Sounds like a plan, thanks again to all for the advice. Sorry to be so hard headed on this one but I do appreciate the help! I've been pulling my hair out trying to find DOT in NZ so gave up on that. I went through the lists of commercially available products and their trade names, nothing available here. But I found an online seller and ordered 2kg of borax, the pentahydrate one, and 2kg of boric acid. I found a couple of websites referencing the home-brew instructions for Tim-bor which I will follow. $30 for the lot shipped, so no harm done.

I haven't found a single hole in the second logs worth of timber yet so I might even keep it seperate after treatment.