Removal of drone brood
The economic benefit for beekeeping operations of removing drone brood as a complementary measure
to control varroa
Since the first article, we have received a large number of requests for clarification regarding the practical implementation
in the hive, followed by many very positive comments on the effects of this “mechanical treatment,” which poses no risk to bees or the queen. After recalling the context of the study and the way it was conducted, we now present the complete results over a two-year period.
Drone brood removal as a Varroa control strategy – biological and economic benefits
This study evaluates the systematic removal of drone brood as a complementary method for controlling Varroa destructor. The approach is based on the mite’s strong preference for reproducing in drone brood, where its reproductive success is much higher than in worker brood.
The field trial was conducted over two years (2016–2017) on approximately 400 Dadant-managed colonies. Colonies were divided into two groups: a control group without drone brood removal and a test group in which drone frames were introduced and removed in spring (April–May), shortly before emergence. All colonies also received standard summer and autumn Varroa treatments.
Results show that removed drone brood contained very high numbers of Varroa mites. Overall analyses indicate that about 30% of the mite population can be mechanically eliminated through drone brood removal. When combined with conventional treatments, this significantly lowers both the minimum and maximum seasonal Varroa load.
Colony performance benefited from this reduction. Test colonies were stronger in spring, developed more dynamically and experienced lower winter mortality. No negative effects were observed on queen mating success or general colony productivity.
From an economic perspective, honey yields were higher in colonies with drone brood removal, with increases of around 16% in spring and 9% in summer. High-quality wax recovered from drone brood provided an additional benefit. Extra costs were mainly related to labor and remained limited. The overall economic balance showed a net gain of approximately €35 per colony over two years.
The authors emphasize that drone brood removal is not a substitute for acaricide treatments but an effective complement. Its main advantage lies in reducing early-season Varroa pressure, thereby enhancing the effectiveness of subsequent treatments.
In conclusion, systematic drone brood removal is a biologically effective, practical and economically profitable component of integrated Varroa management, particularly suited to professional beekeeping operations.
See also:
- Varroa destructor
- Varroa resistance
- Varroa saliva and its effects on the bee
- Practical Guide 1.4.1: Drone brood removal
- Integrated varroa control throughout the season