If used intelligently, formic acid can be effective and have little or no harm to brood.

QUOTED MATERIAL:

The 17-h formic acid treatment tested in this study
was an effective varroa mite control technique. Most
notably, under relatively hot ambient temperatures
during a late-season nectar ßow, the 50% formic acid
treatment killed a signiÞcant proportion of varroa
mites in worker brood without increasing queen or
brood mortality.

This short-term fumigation method is
highly advantageous compared with previously used,
long-term methods that had to remain in place for 4wk
to ensure that mites emerging from brood were
treated (Bracey and Fischer 1989). Additionally, prolonged
treatment negatively affects honey bee brood
care and feeding (Bolli et al. 1993). In this study, the
short-term treatment with 50% formic acid for 17 h did
not negatively impact brood production or queen survivorship.

Short-Term Fumigation of Honey Bee (Hymenoptera: Apidae) Colonies
with Formic and Acetic Acids for the Control of
Varroa destructor (Acari: Varroidae)
DENNIS VANENGELSDORP, ROBYN M. UNDERWOOD, AND DIANA L. COX-FOSTER
J. Econ. Entomol. 101(2) (2008)

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