On 6 August, Todd introduced : "the supressive effects of broodless periods on varroa populations. ....I wonder if a usable, chemical free varroa management plan could be built around this concept, without sacrificing too much production?" May I venture that there is an effect, yes, but it can only be only suppressive, and therefore insufficient on its own as a control measure. I surmise (yes, surmise) that noone would want to cage the queen before the 'critical date' - the day after which there is insufficient time for the bee to become a forager - say 1 June in UK. Caging the queen then means all sealed brood would hatch by 3rd week July - and all varooa would then be riding on bees. It is likely two things both then happen - (1) an increase in any tendency within the colony to groom, as the opportunity to groom would increase in proportion ... plus increase in the number of varooa that simply lose their hold and fall to the floor if that can be assumed also to be simply in proportion to the number of 'riders'. PROVIDED that the hive has a mesh floor, and any tray is at least 2 inches below the mesh, those failed jockeys never return. (2) loss of varooa attached to foragers that die in the fields. There do not seem to be many published charts of the variation in colony size thruout the year - I tend to use the 6 charts given by E P Jeffree in a lecture to the UK Central Association of Beekeepers in 1959. They mostly show colonies peaking around end June, followed by a steep drop of up to 25% by end July. So we could expect some 25% of varooa to be lost in action, unless varooa are particularly good at selecting the younger and luckier mounts. Adding the two effects - for a break in egg laying of say 3 weeks - might bring down varooa by what, say 50%? Or is there another mechanism I have overlooked? For that reduction, the colony will pay a penalty from reduction of nurse bees during July. That may be important since less brood rearing in July will lead on to a shortage of nurses in August / September when rearing of winter bees should get going. So there must be some risk of weakening the colony. A way to use the principle of a brood break into a viable control measure is (I suggest) to positively attack the varooa while there is no sealed brood, rather than rely on natural decline. There are so many ways when varooa are exposed - especially if the hive has a mesh floor and so varooa need only be shocked so they lose their grip, not killed outright. Combs can be sprayed for example with perhaps sucrose octanote esters, or simply puffed with talc or icing sugar. One I have up my sleeve for resistant mites is to puff tobacco smaoke upwards thru the mesh floor, with the supers off and the brood covered temporaily with just a mesh screen, so that the smoke can blow thru for a few minutes but the bees not take off - no need to handle the combs unless it is preferred to take out the queen for safety. That leaves just the problem that a complete brood break may leave the colony short of nurses. The method I use is to divide the colony at its brood peak into a broodless swarm (with the queen) and the brood plus nurses. If there are no queencells at the time, the two parts are left in contact for a week, by when 'sueprcedure cells' will have been started in the brood - if there are cells, the two are completely separated straight away. The (broodless) swarm can then be treated for varooa - at present, still with strips - and the queen keeps laying. Three weeks later the brood in the other half has all emerged so that can be treated. That part will also have produced a new queen - which can be substitued for the old queen when the two parts are re-united, so solving swarming for the rest of the season. I feel this is a good example of 'Integrated Pest Management' - evolving new routines that manage both the colony and pests at the same time. The difficulty is of course the labour invoved if the colony is kept in a conventional tired hive with the swarm being kept on the floor and the old brood placed at the top of the pile - you have to keep lifting off all the supers to get at the lower brood nest. The method becomes much easier using a double length box in which the two parts are kept at the same level, separated temporaily by a solid vertical divider. Yes, it is a new pattern of hive - but not original - even so, of no interest to those who feel beekeeping reached perfection with Root's Simplicity hive (virtually the modern Langstoth) around the year 1890. But it is an alternative for beekeepers who want to solve swarming and varooa control and also reduce the sheer labour of handling heavy supers so often. (My supers are also made half width, to take 5 wide-spaced Manley frames - reducing the maxximum weight to 16 pounds.) Other examples of double-length hives are of course L L Langstroth's own twin hives illusted in the frontispiece to the 1977 facsilile edition of Langstroth's Hive and the Honeybee, 1853 - inside Langstroth says his twin hives were the best. A more recent double-length supered hive is shown in BeeSource.com/EOB/Urban Bee Condo/Long Hive, but I do not know details of that. My own pattern of supered double- length hive for deep brood frames (Dartington Long Deep Hive) is now being tried by a number of UK beekeepers, each batch made in Eastern Europe being sold out quickly - so there may (or may not) be independent verification of the method at some time soon . So yes, it may well be possible to establish a cjhemical-free method for varooa control that starts with the principle of a broodless period. Robin Dartington :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and other info --- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::