Johan Calis writes:
>
> Worker brood can be treated with formic acid outside the colony. 30 ml 85%
> formic acid on beer spils together with worker brood combs in one brood
> chamber sized extrudated polystyreen box (easy to make yourself, use
> polyurethane glue) sealed airtight for one and half hour will kill the mites
> and leave the brood undamaged. (The brood has to be at least 9 days old and
> preferably not older than 18 days). The more worker brood you will treat in
> this way, the more mites you will kill. Therefore, other age-structuring hive
> management methods, like queen-arresting in bodies simply with queen
> excluders can very well be used. Always treat at least three batches of
> capped brood!
 
Hi Johan,
 
Thanks for the extra observations.
 
Is the above  method  of  administering  formic  acid  temperature
dependent?   I  know a number are and the dosage can then be a bit
tricky. If it is can anyone offer a thumbrule?
 
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Gordon Scott          [log in to unmask]   Compuserve 100332,3310
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