Powder post beetles
Dear Mr. Manning:
In 1985, I bought an 1807 house located just north of Middletown, Connecticut. There was extensive damage to flooring, joists and sill near the front door, but the powder post beetles that did the damage appeared to be gone. In 1987, I hired a restoration contractor to repair the damage. The flooring he put in was new, but he decided to replace insect-eaten joists and compromised portions of sill - with beams taken from another old structure. There was no visible insect activity in the "new" joists and sill at the time of the restoration project. But some 15 years later, I began to notice little pinholes all of the beams installed by the contractor. I did not think these significant until a fine powder began to sift out of them. By this time, it was 2004. I hired an exterminator. He immediatley identified the problem as the very one I paid the contractor to correct: powder post beetles. The exterminator went into the basement and saturated the affected beams with borates. "That is the end of your PPB problem", he said. 4 years later, while working on the front of the house, I discovered that the front sill has been largely reduced to "talcum powder". I have several questions for you:
1. Do you think it likely that the contractor unwittingly introduced PPB's into the house by using old timbers to restore my house? Is there any scientific way to be sure if that is what happened?
2. Was the exterminator justified in thinking that treating interior surfaces with borates would put an end to PPB infestation, or should he have known it was necessary to treat external surfaces as well?
3. Could the microscopic examination of the frass in my front sill determine when the damage happened?
4. Are there "consulting entomologists" who could determine exactly what happened to my joists and sill by examining the "scene of the crime"?
I look forward to hearing from you and thank you in advance for trying to answer my questions!
First of all, we need to establish the environmental conditions that afford this yet unidentified species the opportunity to propagate. The niche factor is always the same. Creatures will always settle in conditions that afford them the greatest opportunity to assure continuation of their offspring.
There are three families of beetles that can be referred to as powder post beetles. All the rest have similar affinity for woods, can be found in harvested timber, but selected the wood before it was harvested. The families called PPB's are Anobiidae, Lyctidae, and, Bostrichidae.
I'm leaning towards Anobiids. The clues you present are as follows:
1) 1807 New England home. During that era, basements were built of stone. Fields were full of stone. Farmers cleared these
fields, using the stones and boulders for construction of
fences, houses, basements below frame or brick or stone.
2) Basements were often damp. When entering, one felt chilled
to the bone in winter, and overcome by the dampness during the heat of the summer.
3) Thresholds, close to the ground, resting on stone foundation,
adjacent to sill plate or joist, captured chronic moisture, creating the right environment for Anobiid spp to settle in.
The rest of the basement being damp, and of the ideal humidity
required to set up the reproductive setting, the beetles could,
and would continue to breed indefinitely.
Regarding Lyctid beetles, the requirements are quite different. The possibility of continual reproduction presents itself with the ideal wood. The other environmental factors are not so much the humidity and temperature as compared to the availability of the desired species of wood.
With the Lucid, treatment of the wood, using a borate solution, could be successful. The larvae already in the wood, would not be destroyed, for the most part, but the re-infestation possibilities
could be halted.
As to Bostrichids, there are so many species, and they need very particular conditions to successfully propagate their kind. The chance that they would even re-infest wood from which they emerged
is much less likely.
With Anobiids, you simply have to change the humidity factor, and you have eliminated them. Spraying with various insecticides will halt reproduction for a time, but, in the long run, the environment will dictate, the insecticide will cease to protect, and the beetles will still be "marching on".
I hope that I have been helpful. You can, if you wish, fill me in on the details. I think all diagnosticians like feedback.
Chicago Pest Control