While retrieving a queen to aid a beekeeper with a queenless hive earlier this week I noted that this queen was still laying eggs. I assume other hives in our area are about at the same stage. If this queen quit laying the next day (unlikely) that would mean there will still be brood emerging in the fourth week of October. Guess who will also still be emerging! Our nemesis the varroa mite.
For that reason I will be treating my hives twice more with oxalic acid vapor; once in late October and again about the second week of November. Oxalic acid vapor treatments reportedly kill 95% of phoretic mites. I am banking on the November treatment being after the last brood has emerged and will clean up the hive, as far as varroa is concerned, prior to winter. Even if there is still a little brood present the varroa mite levels will be lessened. NOTE: Hives with Italian queens can still be raising brood through mid to late December.
Oxalic acid vapor is also relatively easy on the queen so it is highly unlikely the queen would be harmed. I followed the same late season oxalic acid treatment last year and had 88% winter survival and therefore consider the risk to minimal. As they say "pay your money and take your chances".
This week I am in process of removing any remaining feeders. However, I will probably keep a few on through Thursday. Just prior to then we will have two "warm" days with temperatures getting to the low 60's F. However, the days and nights are getting gradually colder. I see the bees in some hives and nucs have been clustering overnight. Syrup uptake is consequently greatly reduced.