How to control varroa infestation
The aim of varroa control The fundamental aim of varroa control is to keep the mite population below the level where harm is likely, (known as the economic injury level), therefore maintaining healthy colonies of bees for the production of honey and other hive products, and for pollination. It is not necessary to kill every single mite for effective control and it is not usually desirable to attempt this. However, the more mites that are left behind, the quicker they will build up to harmful levels again (see Figure 11). With 80% efficacy the danger level (of 1,000 mites) is reached again in only 65 days, with 90% in 100 days and with 99% population growth is slow so that assessments can be made the following season.
Types of controls Current control methods used by beekeepers against varroa can be divided into two main categories: ‘Varroacides’ – The use of chemicals to kill mites (or otherwise reduce their numbers). These are applied in feed, directly on adult bees, as fumigants, contact strips or by evaporation. These may include authorised proprietary veterinary medicines and unauthorised generic substances.
Richard Ball, CSL National Bee Unit
Mike Brown, CSL National Bee Unit
‘Biotechnical Methods’ – The use of methods based on bee husbandry to reduce the mite population through physical means alone. Many of the most popular and effective methods involve trapping the mites in combs of brood which are then removed and destroyed.
Mike Brown, CSL National Bee Unit
James Morton, CSL National Bee Unit
Figure 27: Oil seed rape, a major UK honey crop
Mike Brown, CSL National Bee Unit
Figure 26: Beekeeper putting in varroacide medicament strips
Figures 28 to 30: Successful beekeeping depends on effective varroa management
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