Dr. Ron Currie at the University of Manitoba, Winnipeg, Man., Canada recently published “Fluvalinate Queen Tabs for Use Against Varroa Jacobsoni Oud.: Efficacy and Impact on Honey Bee, Apis mellifera L., Queen and Colony Performance,” American Bee Journal, Vol. 139 (November 1999), No. 11, pp. 871-876. Queen tabs are plastic strips containing one-percent fluvalinate as active ingredient. They are inserted into queen shipping cages to kill any mites on queens or accompanying attendant bees. This is supposed to prevent mites from being spread through queen introduction.
According to Dr. Currie, although the queen tabs were more than 99 percent effective in killing mites, they did not eliminate the risk of introducing Varroa because all mites were not killed. More important, however, were the effects on caged queens and attendants. Dr. Currie found significant worker mortality and sublethal effects on queens after three days of exposure to 1 percent fluvalinate active ingredient (A.I.). Queen mortality increased after seven days exposure. A 3-day exposure resulted in a 67 percent increase in supersedure rate than found in control queens or those exposed for seven days. The latter anomaly is apparently due to so-called “weaker queens” being killed or damaged by the tabs prior to and/or during introduction. Once introduction was successful, no difference was seen in either queen survival or colony brood production.
Dr. Currie says that queen mortality and supersedure increases shown by the study require consumers to have to purchase from 40 to 52-percent more replacement queens than if tabs were not employed. Given this and the fact that they do not ensure mite-free replacement queens, he does not recommend their continued use. The results presented here provide further evidence that fluvalinate may indeed be responsible for so-called “queen problems” beekeepers have seen in the recent past.
The drone situation appears to also somewhat reflect that of queens. Dr. T. Rinderer and colleagues at the Baton Rouge Bee Laboratory studied the effect of fluvalinate (Apistan®) on developing drones (American Bee Journal, Vol. 139 (1999), No. 2, pp. 134-139. Although the number of drones produced was no different, survival varied significantly. Drones emerging from control colonies where fluvalinate had not been applied were mostly alive (97.5 percent), but those from colonies treated with Apistan® registered a lower (86.1 percent) survival ratio.