Again I was awake and up earlier than usual and was early in the queue for breakfast, skipping the porage as I’d discovered where they’d hidden the muesli and yoghurt.
The first lecture of the day, Tuesday, was Bee Health: What and Where are Our Problems? by Mary Coffey. She knows her stuff and delivered it at the gallop. She talks faster than I can listen! My notes tell me she started with pests, pathogens and pesticides. Varroa undermines the immune system so the bee is more susceptible to viruses and nosema.
Neonicotiniods cause suppression of the immune system and fungicides inhibit de-toxification and both cause increased mortality. Neonic are applied as seed dressing and then enter the growing plant where they become available to the bee via guttation fluid. They’re not toxic but reduce efficiency and homing ability of our bees and also bumble bees.
Carla Sulis is undertaking a protein profile of bees and finds lots of proteins reduced in Varroa-punctured bees.
The COLOSS survey of winter losses had a response of 450 in Ireland -about 15% of beekeepers. Winter losses were 29.5% of which 12.5% were caused by queen problems and the rest dead colonies for no specified reason.
Internationally, 29 countries take part with 18,693 beekeepers responding who own 399,602 colonies. Ireland (both parts) and Wales had the highest losses, but Scotland was ok. There were no data for England. Smaller scale beekeepers had more losses than larger ones through poor Varroa control, age and quality of queens and the crops foraged on: oilseed rape and maize being the worst.
Comb changing – various methods eg Bailey. Queen age: half 2015, half older: not much difference. Insufficient control of Varroa – need good winter bees. The chances of using Bayvarol again successfully are minimal. Apiguard/thymol is about 85% effective but there is high variability. The treatment lasts 6 weeks and the ambient temperature must be above 15 degrees C so do it early.
MAQS is a 7 day treatment with formic acid. Mean efficacy is 70%, ranging between 60% and 99%. There is some mortality of bees and of brood but it is not a huge problem. Only 2 queens were lost. Some mites survived in the brood and reproduced successfully.
Api Bioxal is oxalic acid applied by trickling or by vaporising. It is more than 90% effective in winter.
Conclusions: use Apiguard and oxalic. Treatments are diverse and winter losses high. Nosema ceranae are increasing but Nosema apis is going down. Some have both. More than 90% of colonies have Deformed Wing Virus.