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High Varroa Populations Reported
NBU Alert dated 8th May 2014:
"Many of our Bee Inspectors have reported a high population of Varroa mites in colonies across England and Wales. We believe these high levels are largely due to many colonies continually rearing brood throughout the mild winter. Continuous brood rearing dramatically reduces the efficacy of winter Varroa treatments such as oxalic acid, which do not kill mites sealed in brood cells."
"We urge beekeepers to monitor colonies and check either the natural mite drop from a sticky insert/ open mesh floor or by uncapping drone brood. From May to August, a natural mite drop should be monitored over a week. The number of mites then counted over this week should be multiplied by 30 to give you a rough population of Varroa in your colonies. A figure of 1000 mites or more is considered to be a high infestation. If uncapping drone brood, then only 5 Varroa mites out of 100 uncapped pupae need to be found to be considered a high infestation."
"Should you discover that your colonies have a high amount of Varroa then a range of options are available from biotechnical methods such as drone brood removal, to authorised varroacides. NB Varroacides used will be weather and temperature dependant. If you have supers on your colonies then thymol treatments should not be used due to tainting of the honey. "
More information is available in the NBU leaflet ‘Managing Varroa’, which is available to download from their website.
- Written by Deputy Secretary
On Thursday 13th March 214, the National Bee Unit issued the following starvation warning:
"With the continued mild weather persisting past winter, it is possible that some colonies may be getting low on food reserves. This will be particularly true in warmer areas of the UK where brood may have been reared throughout the winter. If you have not already done so, now is the time to go out and inspect your colonies. Below are a couple of pointers to consider:
- Information received from Regional Bee Inspectors suggests that in some areas, especially in the East of England; colonies in many apiaries are starting to become light.
- Stronger colonies have been rearing small amounts of brood throughout the mild winter, and currently many have at least 2-3 combs of sealed brood and one comb of open brood. With the current forecast suggesting a fairly settled period throughout the rest of the week, now would be a good time to get out to the apiary and see what levels of food your colonies have. Should the weather continue to stay mild and warm, a liquid sugar feed can be used in small quantities, not to overload them; a spring sugar solution of 1kg of sugar to 1300ml of warm water. However should the weather turn cold again, fondant should be switched when the bees stop taking the syrup down.
- Some colonies have had the opportunity to forage on ivy last autumn and so may be heavy, and the bees may be sitting on a lot of hard ivy honey. It is possible that with the milder weather they have been able to get out and gather water – but worth considering when thinking about how much food colonies have and whether they can access it.
- It is possible that over the winter, Varroa may have continued to breed, it is therefore important to monitor the natural drop of the mite. In extreme cases it may be necessary to think about a spring treatment to bring numbers down, particularly where no treatments have been used since late last summer."
- Written by Deputy Secretary