When I think of woodborer damage, I think of the galleries created under the bark as the main indication of their presence. On the outside of the bark you are only likely to find a few holes created after they mature and fly away. Are you seeing a lot of holes that are evenly spaced? Because that would indicate the presence of sapsuckers. If you are not familiar with this do a google image search for "sapsucker holes" to see what I mean.

The best way to combat most borer problems is to maintain healthy and vigorous trees. Borers preferentially attack unhealthy trees and don't often have significant impact on healthy ones.

In some cases, plagues of certain (generally exotic) insects may widely attack a certain species. In these cases, it's usually best to check with your local ag extension agent for possible specific control measures.

Sorry, but I think the fan idea may be a little....well, crazy. LOL

No, I know what woodpecker holes look like. These are spots in the bark that continually weep water.

Stirring the air around the trunk to draw the warmth out of the bark in an attempt to freeze the borers may not be as crazy as you think. It calls to mind the trick farmers in Fla utilize to keep frosts from ruining their fruit, that is to spray with water before the freeze. It's the opposite of what I want to accomplish but it may be worth a try. I'll let you guys know next year.

Does anyone have any experience with pesticidal tape?

. . .and thank you all for your contributions,

Doug

The tape works well for certain types of insects, but is useless against many others. You need to identify the specific type of tree(s) you are dealing with and the specific type of borer. The solution to your problem will depend on what you're dealing with. You could try all kinds of things and possible never solve the problem without a proper ID. Also, there may be little need to reinvent the wheel if good wheels are widely available. Check with your local extension office. If you can ID the problem first, that might be helpful, but if you can't, they may be able to help there also.