I recently installed a maple wood floor in a bedroom of my house. Before sanding and sealing I noticed the evidence of powderpost beetles, small holes and small piles of powdery sawdust. I obtained some Boracare and applied it to the floor per instructions. After completely drying, I sanded and sealed the floor. Within a few days, more holes and sawdust appeared. My question is; did the treatment of Boracare not work, or was it not thorough enough, or am I witnessing the end of the beetle life cycle that will now be stopped because of the Boracare? Do I have to sand and retreat the floor again?
Thank you for your help.
There is no need to treat again. As explained in our Powderpost Beetle Control Article, there are pupa casings in the wood which are not susceptible to the Boracare treatment. This third stage of the powderpost beetle is where larva molt to adults. When ready, the pupa casings will hatch and the exiting adults leave the powdery sawdust and tiny holes you’re now finding. If done properly, the Boracare treatment should have penetrated the wood through and through. If so, any hatching larva still in the wood which feeds on the now treated flooring will die. Remember, adults do not feed but if they return to this wood and lay eggs, in theory hatching larva from these eggs should not be able to survive. In other words, over time your problem should dissolve and be gone.
In summary, what you’re experiencing is quite normal and to be expected until the infestation runs full cycle. In this case, you will experience new exit holes continuously until all the pupa inside the wood have hatched and adults exited. I’m sure this answer does not make you feel better and has to make you wonder how long this can go on? Unfortunately, this is not a question I can accurately answer. I have seen exit holes occur for just a few days following Boracare treatments. My guess in these situations the infestation was small. On the flipside, I’ve seen exit holes continue for six months or longer. This would be the extreme situation and not common. In most cases, the existing pupa population will hatch out within one to three months.