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treatment in 2006
The 2007 season has been difficult, throughout the UK. In my case, I treated only a few colonies with high mite falls for varroa in late 2006, in the hope that I could identify those colonies in the remainder that could manage varroa well. None of these colonies had a high mite count and several showed high rates of chewing pupae. This was indeed an optimistic strategy and I do not recommend it, except in cases where there seems to be good evidence from mite fall and bee behaviour, that treatment can be deferred, as in the IPM strategy. Even then, not treating a sample of the best might be more circumspect. It appears that a low mite fall in September is no guarantee of survival through the winter. All colonies were treated with thymol in the spring, at a rate of ½ gramme per frame top, over the brood nest and two additional frames. In most cases, 2 treatments were given and a few had 3 treatments.
The pattern of strength and weakness was a surprise, though statistically there may have been no significance. Whole apiaries (6-8 colonies) were all strong or all weak, whilst others were 50:50 or poorer. Almost all of the new queen colonies survived well and expanded well, though some in an apiary where many colonies died out, also died out. It is tempting to surmise that where one or two colonies in an apiary collapsed with too many varroa, the other colonies acquired a great deal of the varroa during robbing, thus giving rise to a knock on effect. Or apiaries surrounded by colonies which collapsed brought additional varroa into the apiary. No winter mite falls had been measured to ascertain the strength of any varroa increase, a recomended strategy. Nuclei from the previous year's overwintered batch replaced those that did not survive and all expanded rapidly on the early spring flow.
equalising and rearing
From colonies that were very strong, two early breeders were selected, having other characters that supported this choice: black, early foragers and well-tempered. One of these had not been treated for 2 years and was used by my friend Ben in his commercial operation, in exchange for assistance in queen rearing. The remaining strong colonies were used to provide frames for the less strong colonies to "equalise" them.
feeding
The spring flow was promising and some colonies collected a super of honey. However, the remainder of the season was unusual and though colonies remained strong, they seemed to need to use all income and most of their stores to do this and only started to create a surplus in late July and early August, close to the end of our summer bramble flow. Many colonies have little stored around the brood. My colleague Rodger Dewhurst used copious amounts of sugar to maintain his colonies in good shape and moved some to the heather successfully.
rearing and treatment
Late queen rearing is from the strong colonies mentioned, which show little or no chalk brood and which also show high pupal damage. The best of these is from a line whose progeny has overwintered well and grow rapidly in the spring. My intention is to use the cells produced as supercedure cells, protected and added to all colonies with less clear varroa reducing characters and a mite count and examination is expected to assist this determination. Mating is expected to be within strain as the mating apiary has colonies still supporting black drones. All colonies will be treated, even if they seem promising.
