As a part of my training yard effort, I often field questions for the beekeepers that my activity reporting message reaches. Currently, the training yard is preparing to produce a few nucs that with some luck, will overwinter.
The question raised is “How late is too late to re-queen a hive?” A great question and one that I don’t have an answer for. My response was “I don’t know” but here is what I consider information that might help and what I do with bees in my yard.
The worker bees that get the hive through the winter are freshly laid eggs around mid August through mid October. As you know, the larva cycle is 3 days egg, nine days to capped cell, ten days to emerge for about 21 total days egg to worker. As you probably also know, the newly emerged worker bees are mostly responsible for “house” work (caring for brood, comb and hive) not “field” work (mostly foraging for nectar, pollen and water).
So if I count the days correctly, an egg laid on August 15th will emerge 21 days later on September 4th. The next egg, if laid on September 4th, will emerge September 25th, then the next cycle on October 16th. Normally after October 16 there has been a frost so blooms are gone so no pollen no nectar. Worker bees have less to do and egg laying is approaching the lowest point of the year.
With this cycle in mind, an older failing queen can’t produce the egg volume needed to replace dying older bees at the same time that the hive is faced with declining nectar and pollen sources. So the bee population declines and the average age of the worker bees increase. This does not bode well for the hive as the increasing age of the worker bees tends to make them more field bees and less house bees. Because of this declining total egg production, the colony is on a downward path and introducing a new queen late can not reverse the process because the worker bees are mostly older field bees, not younger house bee that care for the new queen and her eggs and larva.
So introducing a new queen in September or October is, in my humble thinking, too late to have the desired effect after the cost and effort to re-queen is considered. If the queen is productive in September and October why replace her and how does one make that decision?
Here is what I do – not that I’m right.
I pull any honey in Late June or early July then immediately start controlling for mites. I also combine hives that are weak into one that has a queen with some brood. The mite control products that I use in the July time period are thymol based. This is because formic acid has high ambient temperature restrictions and oxalic acid dribble takes more applications. Neither treat under the capped brood hence the 21+ day treatment process. All mite products have the potential to disrupt the queen’s egg laying and general brood conditions. These chemicals are not without side effects. Thymol treatment lasts 21 or so days (one full brood cycle), finishing in mid to late July depending on how I’m doing with honey removal and starting mite treatment application.
So that puts me into August with hives that hopefully have low mite counts and some amount of brood even if the treatment has had a negative effect on existing brood and the queen. At that point I re-queen and make nucs that can be overwinter as replacements or for sale next spring. Mites and cold weather hit hard this past spring and many hives were lost in February. One process I have added to my tool box is an alcohol based mite check to get some conformation of how well mites were controlled. I did not do this last fall and paid the price.
I’m seriously considering a late fall or early winter oxalic treatment when brood is at a minimum. This would be somewhere around the winter solstice, December 21th and will be new to my beekeeping process.
There is a lot to learn, more question than answers and far too many unproved processes in circulation for me to say I have an answer; I don’t and I’ll will be the first to say that I don’t. I can only tell you what I do and explain my logic.