Sucrocide™ (sucrose octanoate) is registered in the United States for varroa mite control. It is of interest because sucrose octanoate is a natural food additive, and thus safe for use in bee colonies.

But is this really an effective varroa mite treatment for Canadian beekeepers?

Alison Skinner, Janet Tam, Rachel Bannister and Melanie Kempers evaluated Sucrocide™ as a Varroa mite treatment under the Ontario Beekeepers’ Association Tech-Transfer Program. It was one of three projects funded by the Agricultural Adaptation Council (AAC) through the CanAdapt Program from July 2004 to July 2006.

The objective was to determine if the strength of the colony was compromised by the Sucrocide™ treatment, and if it was effective against varroa in Ontario’s conditions.

Spring Trial

Mite-AwayII™, oxalic acid (single application), oxalic acid (double application), Sucrocide™ and no treatment (control) were evaluated to determine their effects on honey bee colony strength and honey production.

Results

The number of frames of brood, bees and honey at 3, 6 and 13 weeks following Sucrocide™ treatment was consistent with the control colonies. The treatment did not raise concerns regarding damage to the colony population. This is consistent with the nature of the treatment and the data collected in US trials.

Colonies treated with Mite-AwayII™ had noticeably less brood than the control colonies after 3 weeks. At 6 and 13 weeks, however, there was more brood in the colonies treated with Mite-AwayII™ than the control colonies. Though the colonies treated with Mite-AwayII™ initially experienced brood damage, these colonies recovered and exceeded the number of frames of bees and brood in the untreated colonies.

Colonies which received an oxalic acid treatment had slightly less brood and bees than the untreated colonies 13 weeks after treatment. Interestingly, colonies which received 2 oxalic acid treatments had more bees than untreated colonies after 13 weeks. The long term effects of a spring oxalic acid treatment and multiple oxalic treatments is not yet understood and neither are recommended for use.

Fall Trial

The efficacy of a fall treatment of Sucrocide™ and trickled oxalic acid against varroa mites was compared in 2005 in a bee yard south of Guelph, Ontario. (Mite-AwayII™ was not used in this trial.)

Results

The post-treatment average varroa mite load was more than triple the pre-treatment mite load for the Sucrocide™ treatment group. In comparison to the other treatments, the post-treatment varroa per 100 bees was twice as high as the mite load in any of the other treatment groups.

Varroa mite populations were maintained by the trickled oxalic acid treatment. There was brood present in the colonies when treatments were applied, however, and therefore, oxalic acid was not expected to be as effective as if it had been properly applied, later in the fall, when colonies are broodless.

Conclusion

Based on these trials and others, the Tech-Transfer Program researchers concluded that the Sucrocide™ treatment did not show promise as a control method for varroa mites in Ontario. Although it was not harmful to expose the bee colony to Sucrocide™, the treatment application time was lengthy and, most importantly, the Sucrocide™ treatment was not effective to control varroa mites.

Thanks to Alison Skinner, Technology Transfer Specialist, Ontario Beekeepers Association, for providing her team’s report: The evaluation of Sucrocide™ as a treatment to control varroa mites (PDF file)