>>I treated with vaporized Oxalic last November, and had a wide range of success. Some colonies had a large population of Varroa in early summer, while I could find none in some yards. I'm guessing that colonies with brood was the problem.

For this reason, among others, I prefer to dribble.  I need to open the hives and look at the frames.  It takes little time to check a couple of the center frames for brood.

Not that I could do anything about any colonies with brood.  Other than, delaying the treatment and waiting/hoping for another nice day... :)

Colonies with brood in the middle of winter...could they be headed by very young, late summer queens?  Any thoughts?

Waldemar
Long Island, NY

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