Using varroacides
When should you treat?
James Morton, CSL National Bee Unit
Richard Ball, CSL National Bee Unit
There is no single ideal time for treatment with varroacides. However, for most beekeepers the main treatment time is late summer to early autumn – between harvesting honey and preparing colonies for winter. At this time colony size will be reducing while infestation will be continuing to increase. The aim of treatment is to significantly reduce the mite population to protect the last few brood cycles that produce the young bees needed for successful colony survival over winter.
Figures 39 and 40: Proprietary Varroacide treatment strips in use (currently in the UK either Apistan or Bayvarol)
It is also relatively common to treat colonies in the spring – especially where monitoring suggests that they have emerged from winter with a mite population that will pose a serious risk before the late summer treatment.
Selwyn Wilkins, CSL National Bee Unit
Richard Ball, CSL National Bee Unit
The choice of treatment may dictate when treatment is applied. Some (e.g. Apiguard) may require warm conditions for maximum efficacy. Others (oxalic and lactic acid) require broodless periods to be effective and so are usually applied very late in the year.
Figures 41 and 42: Apiguard treatments
Generally beekeepers prefer to avoid treating during the active season when supers are on the hive to minimise the risk of leaving residues in bee products. However, some proprietary treatments (e.g. Apistan and Bayvarol) can be used quite safely during a honey flow if necessary (although not during comb honey production). This is useful if unexpected serious infestation demands emergency treatment. No mention of alternative, unauthorised, products in this leaflet should be taken as an endorsement of efficacy, safety, or a recommendation to treat. They are referred to because they are commonly available.
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