The 2025 New Zealand Colony Loss Survey has identified varroa mites as the primary cause of significant losses among honeybee colonies. These external parasites, which feed on adult honeybees and infect developing larvae, have led to alarming consequences in the beekeeping community.

Varroa mites weaken bee populations, making them vulnerable to diseases and contributing to the collapse of entire colonies. The survey revealed that losses attributed to varroa and associated complications have reached unprecedented levels since the survey’s inception in 2015.

An estimated seven percent of all healthy colonies perished over the winter due to issues related to varroa mites. Notably, the losses from varroa exceeded those attributed to queen problems, starvation, wasp attacks, and other factors combined.

Colony losses were particularly pronounced in the lower South Island, where higher levels of mortality were observed. The survey reported that approximately 63,435 colonies succumbed during the winter, marking an increase in loss rates compared to previous years, thereby reversing a trend of declining winter losses.

Regional Insights on Colony Losses

Despite the upward trend, the survey indicated that the current loss rates still remain below the peak recorded in 2021. These findings highlight a geographic disparity in colony survival, with the lower South Island experiencing the highest mortality rates, which suggests persistent regional pressures affecting beekeeping practices.

Effective Wasp Control Strategies

In addition to evaluating colony losses, the 2025 survey shed light on wasp control measures employed by beekeepers. Wasps are known to pose significant threats to bee populations by competing for food resources. Accordingly, effective controls can indirectly benefit colony health.

The findings revealed that 49% of beekeepers actively engage in wasp control, with about half employing traps and 41% actively destroying wasp nests. Additionally, 33% reported using indirect control methods, such as baiting. Collectively, beekeepers estimated they eliminated approximately 12,200 wasp nests in the past year.

This proactive approach to controlling wasp populations not only helps safeguard bee colonies but also mitigates potential environmental and economic damages caused by unchecked wasp populations.

A Comprehensive Assessment of Colony Health

Conducted by researchers at the Bioeconomy Science Institute Maiangi Taiao, the New Zealand Colony Loss Survey provides critical insights into honeybee health and winter survival rates. This research adheres to an international standard formulated by the COLOSS honeybee research association, designed to monitor colony loss rates and the factors stressing beekeepers.

The survey’s latest findings pertain to winter losses experienced in 2025 and were published on April 2, 2026. This year, data was gathered from 1,948 beekeepers managing a total of 148,460 colonies, enabling estimations across the national population, which stands at approximately 495,587 colonies.