We discourage medicating for Varroa Mite unless necessary. There are cases of the mites developing resistance to the medications. The resistance is largely due to improper use; however, it is best not to use them unless needed. In order to know if you need to treat, you must monitor your mite load, by either doing a sugar shake (How to do a sugar shake?) or an ether roll. In northeastern U.S., if you have 3-4 mites in a sugar shake in the spring or 10-12 in the fall, you need to treat. This is just a general rule of thumb and never an absolute.