Varroa still a problem in the 21st century – IBRA conference report

by Pete Kennedy, St Albans BKA
The International Bee Research Association (IBRA) held a conference at the University of Worcester on Saturday, 29th January, on what is considered by many as still the greatest threat for beekeeping:  the parasitic mite Varroa destructor.  The event was well attended with over 180 delegates registered and the lecture hall packed close to capacity.  No surprise considering the quality of speakers invited.
  • Dr Stephen Martin (Sheffield University) led the packed programme of talks by summarising what is known about varroa biology and offered some hope in how current US work on sequencing the varroa genome may further aid our understanding of its biology.
  • Dr Joachim de Miranda (Swedish University of Agricultural Sciences) followed and spoke about the long association between honey bees and their viruses, and how the arrival of varroa changed this relationship.  An EU-funded project is currently underway developing a diagnostic device (similar to that used for AFB and EFB) to help beekeepers and researcher test for 6 common viruses in their colonies.
  • Dr Max Watkins (Vita (Europe) Ltd) spoke about chemical control of varroa, costs & effort involved in developing & registering a new product, and the benefits of using a registered vs unregistered (often not fully tested) products.  On a question of whether varroa could develop resistance to thymol, he explained that it is theoretically possible but none has been seen so far.
  • Prof. Keith Delaplane (University of Georgia, USA) focussed on IPM approaches to deal with varroa.  Emphasis is on utilising a variety of control tactics acting on different stages of its life history.  Although they may differ in effectiveness, it is the combination and/or rotation of approaches that is important.  Chemicals are still part of the arsenal, but utilised within a programme of tactics as a last resort based on thresholds, thus reducing side effects and residues.
  • Dr. David Chandler (University of Warwick) explained how commercial growers of greenhouse crops have used IPM for over 50 years and now rarely resort to chemicals.  Despite parallels between greenhouses and bee hives, being controlled environments in which chemical resistance by pests is an issue, he emphasised the in-depth knowledge and variety of control options needed.  He presented work on entomopathogenic fungi, from around the world, as a promising option within varroa IPM.
  • Norman Carreck (IBRA & University of Sussex) reviewed progress in breeding honey bees for varroa tolerance but emphasised caution:  Some examples of untreated colonies surviving have on closer inspection been due to isolated changes in the varroa mite rather honey bee tolerance.  The COLOSS project is currently testing 16 strains across 16 countries to evaluate them under standardized test conditions.  Work at Sussex is using DNA markers to guide efforts in breeding for hygienic behaviour.
  • Dr Jochen Pflugfelder (Swiss Bee Research Centre) concluded the day by summarising research directions and priorities identified at recent international research workshops focussed on varroa.  The number of such recent events draws attention to the continuing problem varroa still represents in the 21st century.
In the words of Keith Delaplane, the 1-day IBRA conference offered a “good bang for the buck”.  A book based on the conference will be published in April.  If you are interested in research related to bees, then why not check out IBRA’s website ( and consider becoming a member.

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