The way these pathogens work is that once the environment is sufficiently dense with their spores there is no stopping them. There are certain continents where you just can't grow bananas for this reason. That's why they're burning the bees with the equipment, to prevent it from spreading.

So what's to stop your neighbor from paying the high premiums, getting infected, and then a wayward bee carries the infection to your uninsured hives? As much as it would be nice to protect the bottom line for each farmer, it's far more important to protect the environment's compatibility with bees, and thats not a game that insurance is set up to play.

Yes, and coverage or discounts could be predicated on risk-reducing precautions.