Stress Testing Varroa Treatment Regimes

Based on post of 19 November 2024 on thewalrusandthehoneybee.com

01:30 The damage caused by varroa mites - leading cause of colony losses worldwide

03:30 Learning to keep bees alive

04:00 Current trend among hobby beekeepers for going treatment-free

06:00 USA honey bee colony losses, deformed wing virus

07:45 Using an alcohol wash to monitor mite infestation

09:00 Randy Oliver spreadsheet model

10:20 Available mite treatments, using them properly, resistance to treatment

14:00 Extended release oxalic acid - not yet approved in UK

15:40 Mechanical methods, drone comb removal, caging queens - brood break

20:00 Samples of bees don't always give accurate results, what to do if mite numbers are high in June

24:00 Trying different scenarios in the spreadsheet model, one treatment per year - not sustainable

26:30 deciding on the starting number of mites to use in the model

26:50 The four measures I look for when evaluating a treatment regime: starting mites, ending mites, peak number of mites, number of mites in September (winter bees)

30:15 Two treatments per season - autumn and winter. Timing of oxalic acid treatment in winter, when are they broodless.

31:45 The two treatment regime does ok. The only problem is that there is not a huge amount of leeway, so if the winter oxalic was not fully effective the starting number of mites would be potentially high enough to cause problems before the autumn treatment.

33:00 Three treatments per season, spring amitraz, autumn formic, winter oxalic - this regime is bulletproof and pretty well guarantees control of varroa mites throughout the season. The difference between three treatments versus two is massive.

36:15 Balancing damage by mites against putting chemicals in hives

37:00 Importance of keeping the good genetics in our honey bees, such as gentle, low swarming, high honey production. By not treating I lose most of my bees and most of those favourable genetics, is it really worth it to have varroa resistant bees that have lost the traits that I want

39:30 Most bee farmers will treat for varroa and not raise varroa resistant bees. The only way to successfully breed varroa resistant bees will be to find a place far away from any bee farmers - very hard to do in the UK

40:30 Downside of three treatment regime - no point doing alcohol wash, cannot spot the queens that have varroa resistant bees in their colonies

42:00 Stress testing as above but with a brood-break due to caging the queen. Three treatments per season still wins. My conclusion is that the brood break strategy is not worth the effort, but it may work for others, especially countries with more stable weather.

44:45 Thymol effect on laying rate of queens, oxalic acid trickle versus sublimation

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