Varroa After the Honey Harvest
Every Day Counts Post-Honey Harvest
Why We Immediately Reduce Varroa
With the end of the linden nectar flow, honey harvesting also wraps up across many parts of Germany. Supers are removed, honey is extracted, and for many beekeepers, it seems the busiest time of the year is over.
From our perspective, however, the most critical phase for the health of the colonies is just beginning.
In the upcoming weeks, it will be determined if a colony can produce healthy winter bees or if high Varroa levels and the viruses they transmit lay the groundwork for future overwintering issues.
The Real Threat Isn’t Just the Mites
The Varroa mite harms bees not just by feeding on their fat body tissue. The main issue is that it simultaneously transmits numerous viruses and spreads them within the colony.
As long as the mite count is low, colonies can often compensate for many of these viruses. However, with each mite generation, both the number of parasites and the viral load in the entire colony increase.
Consequently, more young bees are damaged during their development. This often goes unnoticed at first glance, with the real consequences appearing weeks or months later.
Why Time Shouldn’t Be Wasted Now
After the honey harvest, most production colonies still have large brood areas. These are ideal conditions for the Varroa mite.
Every mite that remains in the colony now can continue reproducing within the capped brood. A few hundred mites can quickly multiply into significantly more.
At the same time, new bees are constantly emerging, which have already been exposed to mites and viruses during their development.
These emerging generations will soon take care of the later winter bees. If these nurse bees are already damaged, it immediately impacts the quality of the winter bees.
Why Healthy Winter Bees Matter
Winter bees differ significantly from summer bees. They have to live for several months and therefore have particularly developed fat bodies.
These fat bodies serve as energy and protein stores, perform important functions in the immune system, and enable bees to raise brood again in early spring.
If winter bees are raised by weakened nurse bees or develop under high viral load, bees often emerge with reduced fat body reserves, shorter lifespans, and significantly poorer overwintering capabilities.
This development is difficult to correct later.
The Biggest Mistakes Occur After the Honey Harvest
Many colonies still appear strong in mid-July. There is active flight activity, queens are laying, and everything seems fine externally.
This is precisely what makes Varroa so dangerous.
The real development takes place hidden from view. A significant portion of the mites is protected within the capped brood. From the outside, it’s hardly visible how much the population has already developed.
When many mites suddenly appear on the bottom board in August or September, or when initial damages become visible, the peak of development has often already passed.
The consequences then directly affect the bee generations responsible for overwintering.
Infestation-Oriented Treatment – Sensible, but Demanding
In recent years, infestation-oriented Varroa control has been increasingly recommended.
We fundamentally find this approach sensible.
However, it requires that beekeepers know their colonies well and can interpret the results correctly.
This involves not only determining the mite infestation but also assessing colony development, brood quantity, reinvasion from neighboring stands, the season, and the speed at which mite infestation can change.
A single measurement never tells the whole story.
Why the Effort Is Often Underestimated
Those who work based on infestation need to regularly check their colonies, recognize developments, and react at the right moment.
In our experience, this effort is often underestimated.
For many hobby beekeepers, there is a risk of underestimating the actual infestation or missing the optimal timing for an effective measure.
Our Approach Post-Last Honey Harvest
Every beekeeper develops their own approach over the years.
We do not want to provide a general treatment recommendation, but rather share how we have successfully operated for many years.
Immediately after the last honey harvest, we perform a Total Brood Removal (TBR) with our production colonies.
This removes the majority of the Varroa mites along with the brood from the production colony. The remaining colony is then brood-free and set on fresh foundation. It must be fed abundantly immediately. We use sugar water at a 1:1 ratio.
Before the first newly laid brood is capped again, we treat the colony twice, three days apart with oxalic acid.
With this approach, we have had very good experiences over many years. Our goal is to massively reduce Varroa pressure immediately after the honey harvest and to create optimal conditions for the colonies in the coming weeks.
Splits Also Included
Splits, mating units, and young colonies should not be forgotten now.
Smaller units, in particular, can suffer significant damage from increasing Varroa infestation in a short time. Therefore, they naturally belong in their own Varroa strategy.
Conclusion
Although the honey harvest ends the nectar season, it simultaneously marks the beginning of the most crucial phase for winter preparation.
It’s not just winter bees that need protection. It’s crucial that the bee generations that will raise the winter bees in a few weeks remain healthy.
Therefore, from our perspective, every single day counts after the last honey harvest.
The sooner Varroa pressure is significantly reduced, the lower the viral load in the colony and the better the conditions for healthy nurse bees, robust winter bees, and strong colonies in the coming spring.
The Varroa mite doesn’t take a break after the honey harvest. Neither do we.
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