How common is the common cold? About the same.(G)
I stuff mothballs in the boom to keep the critters out in the off season. Had 'em in the boom, not the mast, I'd guess it depends on how hot your mast gets and how convenient other places are.
There are sprays like "Hot Shot" that squirt 25 feet to kill bees, if you can reach them with that, or something like that, you're safer. If you have an access panel at deck
level (like deck-stepped masts have) or any other place from below where you can stuff in mothballs, or a "fogger" type insecticide, that's safer still.
They don't move around much when they get cold--so they're less likely to be able to attack you if you attack them when it is colder out.