From 2,000 to 0 Varroa In 8 Months
Background
I thought it worth posting the timeline that reduced the varroa to zero and put out a positive message that beekeepers can significantly reduce high varroa levels.
- Hive Two went from counts of 2,000 varroa in December 2013 to zero varroa by the end of July 2014
- My interventions: Open Mesh Floor (all year), Apiguard (Aug/Sep), Oxalic acid (Dec), drone culling (May)
- Bee interventions: Swarming (May) and a Supercedure (July)
- Lessons Learnt: (1) I’m not sure of accuracy of the varroa estimates; (2) be proactive and drone culling seems to be especially effective; (3) don’t worry too much if you have high varroa, because you can do something about it
The Timeline, Varroa Counts & Interventions
I use an open mesh floor and count the varroa on the board I place below. I then use the varroa calculator provided by the National Bee Unit to estimate numbers of mites in the colony.
- 24th August 2013 – Estimated number of varroa: 290
- 24th August 2013 – Added first dose of Apiguard
- 7th September 2013 – Added second dose of Apiguard
- 18th September 2013 – Discovered that Hive One had died of starvation, so removed Apiguard and fed this hive (Hive Two). Hence, colony had 25 days of Apiguard treatment – 3 days short of the ideal
- 8th December 2013: Estimated number of varroa: 2,000
- 21st December 2013: Estimated number of varroa: 1,700 (I did this as I could not believe the first count)
- 21st December 2013: Trickled oxalic acid
- 19th January 2014: Estimated number of varroa: 980 (i.e. 40% reduction; it was a mild winter so there would have been a fair amount of capped brood containing varroa)
- 15th March 2014: Estimated number of varroa: 17-140 (strange result as I had not applied any further treatment)
- 3rd May 2014: Culled drone comb (I believe this was a key intervention)
- 18th May 2014: Hive swarmed
- 24th May 2014: Estimated number of varroa: 1
- 14th June 2014: First time I saw eggs after the swarm (hence mated Queen again)
- 6th July 2014: Witnessed a Queen hatching out – confident it was supercedure
- 20th July 2014: Saw eggs – so laying Queen again
- 26th July: 2014: Estimated number of varroa: 0
- August 2014: Decided not to use Apiguard due to zero varroa
Read More
- Post: 2,000 Varroa In Hive Two
- Details: Hive Two Record Card
- A How-To Guide: Varroa Management
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Could you please tell me what you mean by drone culling and when exactly did you carry it out.What triggered it?
Varroa mites prefer drone brood over worker brood as the drone brood is a capped larvae for longer allowing the varroa to reproduce more. The principle is the majority of varroa go into the drone brood and then you remove this drone brood when it’s capped – hence, reducing the varroa. There are two methods I know of: (A) using drone foundation and then freezing it; (B) using a shorter frame in the brood box (e.g. a super in a national brood box) and then when they have grown the drone comb and capped it, cut it off and remove it. Both methods are used in about April/May in the UK. I used option B this year, but plan on using option A next year.
More information at Varroa Management.