This 'bait comb' process has now become quite complicated so I've made up a chart telling me exactly what jobs I need to do with each separate colony during the next few weeks. Many of the timings required are fairly precise and with 5 colonies to monitor now I need to be able to check every day just when I need to carry out each part of the process.
The red arrows show when each queen will hatch out and the green arrows show when the last of the 'old' brood will hatch. The periods I need to insert the bait combs are when there is no other unsealed larvae in each colony for the mites to breed in - the few days between the last 'old' brood hatching out and before the 'new' brood from the next queen is sealed (9 days after she has finished her mating flights, which she begins 4-10 days after hatching).If I can insert bait combs to cover these exact days (it is not possible to pinpoint them precisely because I cannot predict when each queen will mate, just estimate when it is most likely) then there will be nowhere else for every varroa mite to breed, but in these bait combs.
Destroying these combs before the varroa hatch should reduce the level of infestation to the smallest amount possible. It will mean sacrificing a quantity of healthy bee brood but it seems to be necessary in this situation.
