What is supposed to stop varrona mites - full plastic combs.

Downside - it seems queens won't lay in 'em - thus I lost the one hive I put the plastic in.

I attended our local beekeeper's school this weekend, and one of the big entomology experts from NC State was there to talk about various bee diseases, parasites, etc. We got a good state-of-the-art briefing. He didn't even mention using plastic combs, probably for the reason that you discovered.

Actually, plain old confectioner's sugar holds great promise. Seems that the mites can't keep their grip on the bees when they are coated with confectioner's sugar. They fall off, and can thus be removed from the bees. Since it is sugar, for the bees it is a feast.

This procedure is used on a small scale now in order to get an approximate count of mite infestation. If one were to get most or all of the bees into some sort of cage (probably using a one-way passage like what is used to clear a super for harvesting), they could then be dusted in the cage, the mites would fall out of the bottom with the extra sugar, and then you return the miteless bees to the hive. There is research going into such a scaled-up approach right now, and it looks pretty hopeful.

Using the larger cell foundations to encourage the laying of drones to trap the mites (which lay preferentially on drone larvae) - you pull out the frame before they emerge and either freeze them, or let them emerge within a cage and dust them with sugar per above before returning to the hive -- is another approach. It helps, but even repeating it almost constantly won't do much more than keep the mite population down a bit.

The screened bottom boards reduce Varroa mite populations by about 10%. That by itself is probably not going to be quite enough, but every bit helps, and it is an easy thing to do.

With each generation, some strains of bees are becoming more resistant. With a little bit of intelligent help, they can eventually be pulled through and this will become a relatively minor problem.

I went to a bee-keeping seminar this last weekend,and am getting 5 hives this april.This is the same information I have got on Varroa control,plastic comb foundation making smaller cells,confectioners sugar,drone comb destruction....the symbiosis between bee-keeper and hive is growing...

With each generation, some strains of bees are becoming more resistant.

Most small bee keepers lack the tools to do the artifical insemination, so that is not a claim I'd make.

Most small beekeepers are becoming more dependent upon professional breeders for their stock than used to be the case. Beekeeping used to be a very easy hobby. Now it is becomming much more complicated and difficult. Nevertheless, there are still people eager to have a go at it, judging from the three hundred people who attended our Western NC bee school last weekend.

IAPV, first described in Israel in 2002, came to national and
international attention in September when university and ARS
scientists showed a strong association between the presence of IAPV
and CCD.
ARS has begun several experiments to determine what factors may be
most involved in CCD. Combinations of four areas are being examined:
pathogens, parasites, environmental stresses, and bee management
stresses such as poor nutrition.
CCD became a matter of concern in the winter of 2006-2007 when some
beekeepers began reporting losses of 30 to 90 percent of their hives.
While colony losses are not unexpected during winter weather, the
magnitude and rapidity of loss suffered by some beekeepers was highly
unusual.
Pollination is a critical element in agriculture, since honey bees
pollinate more than 130 crops in the United States and add $15
billion in crop value annually.
There were enough honey bees to provide pollination for U.S.
agriculture this year, but beekeepers could face a serious problem
next year and beyond if CCD becomes more widespread and no treatment
is developed.
Poor nutrition is the one area that could be adressed to effect a
cure. Meaning there has to be more then one source of food , a
solution would be that in the orchard or field the grower would have
to plant rows of wild flowers so the bees would have a source of food
other then the growers cash crop.

I know that CCD is not exclusively a problem of migratory hives, but they did appear to be the ones that got hit the worst. I am still wondering, too, to what extent the non-migratory hives that got hit might have been within contact range of migratory hives.

I really have serious doubts about the long-term sustainability of the whole migratory model. This goes beyond the energy costs of hauling hives around the country and hauling produce long distances, although that is a big part of it. The constant shuffle of hives around the country is about as far opposite from isolation and quarantine that one can get, which thus opens up efficient vectors for the transmission of parasites and disease (like IAPV). It is hard to believe that the constant relocation of the hives does not stress them terribly. Add to that the heavy exposure to a wide variety of pesticides (residues, at the least), the lack of variety of pollen and nectar at any one site, the heavy dosing of hives with antibiotics and chemicals, and it is really a wonder that any of the bees survive. We can't be going on doing things this way forever.