Experiment 4

Section 3: Evaluation of non-chemical methods for Varroa and Nosema management

Deliverable 3.4: Evaluation of syrup additive substances

Implementing body of the Deliverable: THYMOS Beekeeping Cooperative

Purpose of the experiment

In this experiment, an evaluation was made of treatments for Nosema management. Thymol, propolis extract, and an antibiotic were used, while there were also control colonies. The antibiotic used was fumagillin, a preparation effective as an indicator. Thymol in syrup is a standard practice among beekeepers. Propolis extract has not been tested extensively for Nosema.

Conclusion

Measurements of population and brood did not show any clear positive or negative effect of the interventions, although it appears that the test colonies had less brood in autumn than the intervention colonies and some average. Because the interventions were carried out after the first and before the second sampling, it is of interest to look at the results of the second sampling more than the others. November data may have been influenced by other parameters that were not controlled in the experiment. What emerges is that fumagillin had the best performance and thymol the worst. It is possible that the presence of thymol in the hive negatively affects bee development.

Measurements of Nosema spores showed a different picture. It appeared that all interventions reduced Nosema spores after the applications, while in the control the numbers increased. Therefore, all interventions had a positive effect on reducing the disease. ANOVA on the mean spore counts across four samplings showed that the control had more spores than the other four interventions (p = 0.001). It seems that Nosema spores decrease even without fumagillin. The use of propolis extract as a familiar material for bees appears promising.