beetles in lumber

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I have powder post beetles in some nice lumber I want to use.  I do not want to apply any surface control due to finishing problems later.  Can I kill the pests with a heat treatment, such as putting the wood in a kiln and heating to say 160 degrees for 30 min.  If so what stages will it kill.

Thanks.

Over the years we have had many customers attempt to kill beetle infestations using nothing but heat. The problem is measuring actual results. There simply is no way to tell if the heat treatment has done anything measurable. There are many reasons for this inherent “measurement” problem including the following:

  • You don’t know if the wood has active beetles right now. Seeing evidence is not a sign it’s active. It could be old; remember frass falling out could be from old exit holes.
  • There is no doubt that heat over 150 degrees will kill adults and larva but the other two stages, eggs and pupa are no so easy to control. There is mixed data on the efficacy when using just heat and currently no real standard or universal minimum.
  • There are countless species of what many people call powderpost beetles. Data would have to be collected for each species and only then could specific numbers be used to control specific infestations. What we do know is certain species can be killed this way with temperatures in the 120-130 degree range. But for others, it may have to be much higher and for some, no level is known.
  • Knowing just what species of beetle you have is next to impossible since there are very few qualified people that can make an exact id. The only way you can know the right minimum temperature to heat the wood will be if you know the species of beetle you are trying to kill.
  • Different wood conducts heat differently making the amount of time required variable based on wood species, density, thickness, moisture content and a whole other list of characteristics. This further complicates the heat treating option big time.
  • Wood processors including wood flooring companies, log cabin makers, lumberyards, furniture makers and many others have all tried to implement heat treating as a way to control and prevent wood beetle infestations. Currently many use such processes. Some are required by law; others do it because it makes them appear to be doing something worthwhile. Upon close observation what we find is there is a huge variation in just what heat levels being used, the actual kiln type being used, the wood grade being processed, etc and in the end, many of these treatments are failing. Should wood be kiln dried? Most certainly yes. But there are too many unanswered questions and standards that need to be set before it can be used as a way to “control” live insect problems.
  • Heat treating is not protecting the wood. Once the wood dries, it’s immediately vulnerable to infestation again and there is no doubt this vulnerability lends itself to re infestations. Some scientists believe there are certain pieces of wood which may have distinct odors from a prior insect infestation which make it more susceptible. It could be odors from the insects or maybe it’s inherent to the specific tree. The point is once wood shows activity it’s likely to have more activity in the future.

In summary, we have had so many people attempt to kiln process or get their lumber kiln processed and then 1-2 years later still have problems that we don’t offer any guidelines on how it must be done. For now, we’re skeptical of the whole process and wonder just what it’s actually doing ( when used to “control” known insect problems). The one thing we know is kiln drying is not a “treatment” but rather a process which should be done when commercially preparing or using wood for some type of product that one day is intended to be sold. But for the average craftsman that’s wanting to use wood infested with beetles for a project they’re about to begin, something more than just heat must be considered.

Does kiln drying kill some stages of wood infesting beetles? Absolutely. Should it be used as a sure fire way to both get rid of a known infestation and to insure no new beetle infestions occur? No way. We feel if you know the lumber you intend on using has some type of beetle problem then it needs to be treated with BORACARE. This does nothing to the wood and once the Boracare treatment has dried and soaked in, the treated wood can be cut, processed and used for anything you’d normally build with it. You mention you “do not want to apply any surface control” and we concur; surface treating products like Timbor are messy and should not be used on raw, unfinished lumber prior to use in construction. They leave visible films and don’t penetrate where all the “action” is most likely centered. But once the raw wood has been cut and installed, using topical products to prevent mold and insect infestations is Ok. These treatments should be considered to be “preventive” at best. Real treatments done on active beetle infestations need to be done with wood penetrating agents like Borcare which in the end will get to the heart of the wood, break the wood beetle cycle currently active and prevent future infestations with it’s lengthy residual. For now, this is clearly the best “treatment” available when live activity is noted.

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