Unfortunatelly the paper is under a payperview wall

Evaluation of spring organic treatments against *Varroa destructor* (Acari:
Varroidae) in honey bee *Apis mellifera* (Hymenoptera: Apidae) colonies in
eastern Canada

Abstract
The objective of this study was to measure the efficacy of two organic acid
treatments, formic acid (FA) and oxalic acid (OA) for the spring control of
*Varroa destructor* (Anderson and Trueman) in honey bee (*Apis mellifera* L.)
colonies. Forty-eight varroa-infested colonies were randomly distributed
amongst six experimental groups (n = 8 colonies per group): one control
group (G1); two groups tested applications of different dosages of a 40 g
OA/l sugar solution 1:1 trickled on bees (G2 and G3); three groups tested
different applications of FA: 35 ml of 65% FA in an absorbent Dri-Loc® pad
(G4); 35 ml of 65% FA poured directly on the hive bottom board (G5) and
MiteAwayII™ (G6). 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 (G4, G5 and G6). G6 colonies had
significantly lower brood build-up during the beekeeping season. Brood
populations at the end of summer were significantly higher in G2 colonies.
Spring honey yield per colony was significantly lower in G6 and higher in
G1. Summer honey flow was significantly lower in G6 and higher in G3 and G5.
During the treatment period, there was an increase of mite drop in all the
treated colonies. Varroa daily drop at the end of the beekeeping season
(September) was significantly higher in G1 and significantly lower in G6.
The average number of dead bees found in front of hives during treatment was
significantly lower in G1, G2 and G3 versus G4, G5 and G6. Results suggest
that varroa control is obtained from all spring treatment options. However,
all groups treated with FA showed slower summer hive population build-up
resulting in reduced honey flow and weaker hives at the end of summer. FA
had an immediate toxic effect on bees that resulted in queen death in five
colonies. The OA treatments that were tested have minimal toxic impacts on
the honey bee colonies.

-- 
Juanse Barros J.
APIZUR S.A.
Carrera 695
Gorbea - CHILE
+56-45-271693
08-3613310
http://apiaraucania.blogspot.com/
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