No natural kill

[BjornBee]

Alot of talk of mite resistance in Ca. and down south. So here is one angle.

Yes big commercial outfits are guilty of using strips on a continual basis. And this adds to the problem. The other is the movement of hives themselves. Here is why...

If a hive in Pa. or any northern climate crashes in winter due to mites, what happens to the mites? And if these hives that crash after being treated with strips, (ie. resistant mites) what happens to the mites in winter?

They die. Weak strains of bees die. Mites with resistance die. Hives that should die do so. Robbing out of dead hives and the movement of resistant mites end with the death of the hive.

But not in the west and south. They move bees back and forth and do not truly let hives with weak genetics and those hives with resistant mites die over winter. Thats why the problem is compounded in these areas. They overwinter in Ca. or down south and then move them back to the north for summer when weather is good again. And thats why its the bigger outfits of the western states and down south who are going to be hit the hardest and first.

Maybe winter kill isn't such a bad thing.

This is where hobbiest and side-liners are going to see big losses from commercial outfits as they move into your areas with these resistant mites.

And it goes on......

[loggermike]

You can add to that the fact that brood raising never really stops for long in the warmer climate areas where most commercial hives are wintered.This leads to explosive levels of varroa that cant be controlled with only one yearly treatment.So the selection process for chemical resistance is speeded up by the multiple treatments of usually the same chemical.Rotation could have bought us more time.Anyway I am sure LOTS of genetically weak hives have died in the West this winter!

[chemistbert]

Use of things like OA could help a ton too. No resistance to physical attack can be developed.

[bjerm2]

Another thought and angle to this is that when they move the hives into your area they also bring in drones that now pass on the weak genetics into you queen operation with open mating. This can become real serious if you have spent time raising queens from good stock just to have them mixed up with bad genetics.
Dan