PROBLEMS & SOLUTIONS: Answers To Your Tough Pest Questions

CARPENTER BEES
Q  I have been treating log homes for carpenter bees for years. Even though I treat the nest hole with residuals it seems that every year I have problems in the same areas with these bees. Will borates stop them? Do you have any suggestions?
 
A  Carpenter bees can be a difficult insect to deal with, especially if the bee has already laid her eggs and has abandoned the “nest,” allowing the larvae to develop.

Residual injections of insecticide or dusting the holes can get to the larvae sometimes but since you do not know how far the tunnel goes or where exactly the larvae are, you may not get to them. You could try probing along the areas adjacent to the entrance hole to find the gallery.

Just sealing the hole can be a problem during nesting time as the female will bore another hole. I do not know of any researchers working with these insects but my observations would indicate that there are pheromones present that the bees can identify and come back to — there has to be something there besides a nice piece of wood.

Borates are not labeled for carpenter bees but I have seen pest management professionals use borates to spray bare wood as they would for wood borers.

In some cases it worked for a while (a season or two) but in others it did not. However, the spraying has to be thorough and get to all of the exposed wood, otherwise I have seen the bees find areas that were missed and start drilling there.

You mentioned this is a recurring problem. If that is the case, perhaps you can identify the homes with carpenter bee problems and come back in the spring when the bees start to emerge. You can identify areas where they will start chewing into the wood. Apply surface applications of residual encapsulated or wettable powder residuals in those areas.

The author is president of George Rambo Consulting Services, Central, S.C. Fax questions to him at 864/654-2447. Or, send questions to him via e-mail at grambo@pctonline.com.