Here are some simple steps. I have found these to be absolutely necessary, even if you're starting with strong genetically resistant stock.
- you must not treat. If you treat, you take a huge step backward, you may contaminate your comb, and you need to start over.
- You must multiply your hives. You must take the hives you have and make more. Buying more does not count. Bought bees are not your bees and are not reliable. You must multiply from your own bees. Enter hard periods (summer or winter) with more bees than you plan on keeping because you will lose some.
- You must allow sick hives to die (or kill the queens yourself). This is important. Suffer not the weak to live. You must eliminate the weak from your stock. I prefer to let them fail on their own, but you may combine or requeen weak hives as necessary. You must not attempt to "save" a dying hive.
- You must multiply from the surviving hives. If there are no surviving hives, you must start over. See step 2. Multiply so that you have more hives than you need because some will die. Again, you must multiply from your own hives. Buying more hives starts the process back at the beginning with those hives.
- You must repeat the process for at least two to three years before you reach a sustainable population. Chances are you will lose more than average for the first couple years, that's why there is such an emphasis on multiplying. Learn strong and efficient methods of multiplying.