Thanks Les and rwlaw for posting this great webinar. I have had the pleasure of hearing Marion Ellis speak on several occasions. He's the expert on varroa. I intend to watch all of this, but it may take a while. If I am not mistaken, Ellis explains mite counts, how many mites your colony can live with and at what point the mites will have an adverse effect on the colony. In other words, treating every time you find a mite on your sticky board is excessive.
rwlaw: Yes, treating when there is brood will only kill the mites that are on adult bees. It's like an iceberg. Beekeepers need to understand the life cycle of the varroa, which Ellis explains.