In the Northern Netherlands, Up to 41.5% of Bee Colonies Didn’t Survive Last Winter

What happened in the apiaries of northern Netherlands? After the winter of 2025-2026, 41.5% of colonies had vanished in the Groningen province. A striking figure that reveals a persistent crisis, but also a mystery that researchers have yet to solve.

High winter mortality taking hold in Dutch apiaries

When the first warm days return, beekeepers open their hives with a certain foreboding. This year again, many found only abnormal silence. In the Netherlands, 24% of domestic honeybee colonies did not survive the winter of 2025-2026, according to Wageningen University & Research.

What is most worrying, however, is not this isolated result. It is the fourth consecutive winter during which national mortality exceeds 20%. In 2024-2025, it already reached 22%. The succession of poor seasons now sketches a durable trend, far harder to explain than a simple period of unfavorable weather.

Marked regional disparities with extreme losses in the country’s north

The national average conceals a striking contrast. In the northern Groningen province, 41.5% of colonies have vanished. At the opposite end of the spectrum, Overijssel records 16.9% losses. A few dozen kilometers can therefore separate two beekeeping realities that are radically different.

Why is the north so severely affected? Researchers remain cautious. Beekeeping practices, floral resources, humidity, local temperatures, or the initial condition of the colonies could all contribute. No single factor yet explains why one hive survives here while another collapses there.

One colony approaches winter as a small town cut off from the world. It must retain warmth, manage its stores, and protect its queen until the flowers return. A lost queen, insufficient food, or a disease established before the cold can break this balance and rapidly doom the entire community.

Varroa remains a major threat despite widespread control efforts

Among the suspects, Varroa destructor bears its name well. This mite parasitizes both adult bees and their brood, while carrying viruses capable of weakening the colony. The scientific network COLOSS describes it as one of the major threats currently weighing on global beekeeping.

Yet Dutch beekeepers know the adversary all too well. During the last winter, 86.9% applied a treatment or control method against Varroa. This high rate shows that the fight is well underway, but it does not guarantee hive survival. The timing of treatment and its effectiveness can change the entire story.

The Asian hornet progresses rapidly and could heighten pressure on colonies

To this almost familiar threat, the Asian hornet now adds itself. Posted near the hives, it captures returning foragers laden with pollen. Its spread is swift: local presence was reported by 24.7% of beekeepers in 2024, rising to 56.4% in 2025.

Its exact role in winter mortality remains uncertain. The predator can reduce foraging sorties, stress the colony, and limit the reserves accumulated before winter. It could therefore act indirectly, like a prolonged siege, rather than causing collapse on its own. Scientists nevertheless expect to see its influence rise in the coming years.

The survey rests on responses from 840 beekeepers, about 8% of the roughly 11,000 active beekeepers in the Netherlands. Integrated into the international COLOSS framework, it helps compare losses and their risk factors. The decisive question remains: what else do researchers need to understand the Groningen die-off?