The first Advanced lecture was Robert Pickard again. His subject was International Beekeeping. He made the point that, with bees being sent around the World in the way they are currently, we need global regulations to go with global beekeeping. This lecture consisted of photographs (basically his holiday snaps!) and anecdotes. As usual with a Pickard talk, it was entertaining and informative.
Then I went to Meg’s lecture on Inspecting for Adult Bee Diseases. As always, the beekeeper should have a mental picture of what looks healthy and investigate anything that departs from that picture.
Meg referred to Acarine, Nosema (both types), Acute Paralysis Virus, Chronic Paralysis Virus, Deformed Wing Virus, Black Queen Cell Virus and K Wing Virus. She suggested that the signs of Acarine are K wings and crawling bees.
Here there is some controversy. Rennie, who first identified Acarine (tracheal mites for American readers), found some crawlers with and some without mite infestation; also, apparently healthy, flying bees with Acarine mites. That was before viruses had been invented. Bailey, the virologist, suggests that there is no direct connection between Acarine and crawling, virus-affected bees, but the indirect connection is that they are both transmitted in the same circumstances: overcrowding in the hive. This forces older bees to rub shoulders with younger ones, allowing mites to transfer to a new generation and also, through broken hairs, allowing viruses to enter through the follicles. John McMullen has done some more recent work but I have been unable to find my copy of his report in a Central Association book of lectures. I know I have it because Norman Carreck who compiled the volume autographed it for me. Maybe I lent it to somebody.
Nosema: ivy honey can cause fermented stores as, when it crystallises, it can leave some watery fluid at the surface. This can cause a touch of dysentery. If you see this on the front of hives as stools, it is probably ok, if smeary, it is worth checking for Nosema. Nosema is nowadays a classed as a microsporidian rather than a protozoan as it used to be known. Nosema apis, the traditional one, causes ‘spring dwindling’ disease whereas the new one, Nosema ceraneae, causes summer damage, resulting possibly in hive collapse. To find out whether your bees have it, take a sample of 30 adult bees. This will give you a 90% chance of finding a 10% infection. Crush their abdomens and add 5 – 10ml of water and stir. Transfer a drop to a slide, cover with a slip and examine under a microscope at 400 magnification or greater. Nosema spores, if present, will appear as if rice grains. You have no chance, as an occasional microscopist of detecting the difference between the two types of Nosema. Even the experts at the National Bee Unit get their initial diagnosis confirmed by other methods (PCR, whatever that stands for) not available to the amateur.
You can treat Nosema with Fumidil where the use of antibiotics is licenced or a blind eye is turned, but that will do nothing to prevent rapid re-infection from soiled combs. So you also need to do a comb change as soon as possible; a Bailey change is recommended, and either destroy the old combs or expose them to the fumes of Acetic acid. There is some suggestion of genetic susceptibility and so it might be worth requeening from a less susceptible strain if you can find one.
With Varroa mites, you must monitor and control. ( I know people who would disagree with this!) Meg displayed a useful graph for deciding whether/when to treat for Varroa. 2 lines zig-zagged from bottom left to top right. If the mite levels are below the bottom line, all is well. If between the lines, keep checking. If above the lines then treat now.
Varroa mites might cause Parasitic Mite Syndrome, the symptoms of which are abnormal brood with bees dying before they can emerge, with wings damaged by the Deformed Wing Virus. Meg showed a photo of a shaved down cell through which the mites could be seen on the pupa. Not a pretty sight!
My final note on Meg’s lecture is that an eke surrounding the Apiguard tray should be 60mm deep. That’s about 2½” in English.