Of course, any discussion of bee mortality due to acid treatments must consider that such
mortality, if it exists, may be far less serious than the damage caused by mites, if left unchecked.

QUOTED MATERIAL:

Formic acid treated colonies ( MiteWipe, Flash, and MiteAwayII TM) showed
good control of varroa build-up. When compared to the control group colonies, FA treated
colonies showed a higher varroa drop during the treatment period, smaller varroa populations
during the summer and lower mite counts during the September control with CheckMiteTM.

FA treated colonies also showed higher levels of adult bee death during treatment, thus
indicating the toxicity of FA on bees. The highest toxicity of FA was measured in colonies
treated with the commercial product MiteAwayIITM. This application of FA killed more bees
than all of the other treatments that were tested and it also reduced brood populations in June.

With the application of MiteAwayIITM, the decrease of varroa populations seemed to have
been achieved at the expense of a reduction of the colony bee population and, consequently, a
reduction in honey production. These results are consistent with previous work showing that
spring treatment with FA may cause a reduction of brood rearing and it may affect the
physiology of the young bees

The efficacy of treatments (varroa drop), colony development, honey yield and hive
survival were monitored from May until September. Five honey bee queens died during
this research, all of which were in the FA treated colonies [ note: 5 out of 24 colonies = 21% ]

Formic acid was applied in three different ways to the remaining treatment groups.

– MiteWipe method: 65% FA was delivered by placing two Dri-Loc pads
(10 x 15 cm) imbedded each with 35 ml of acid on top of frames (posterior portion
of hives) in brood chamber.

– Flash method: 65% FA was delivered by pouring acid (2 ml per frame of bees) directly
on a piece of absorbent ScottTowel paper placed on the bottom board of the hive.

– MiteAwayII TM pads: FA was delivered by using single application of these
commercially available pads.

Evaluation of spring organic treatments against Varroa
destructor (Acari: Varroidae) in honey bee Apis mellifera
(Hymenoptera: Apidae) colonies in eastern Canada
Pierre Giovenazzo • Pascal Dubreuil
Exp Appl Acarol published online: 26 March 2011

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