Cultural/Mechanical/Nonchemical Control Techniques
Even with the most tenacious preventative measures, and even using lines of bees that demonstrate resistance, some colonies will come down with a disease, or the mite levels will increase to the point where treatment is needed or the colony will die. The chances that diseases and mites will spread in an operation will increase with the number colonies and frequency they are moved together on trucks and placed in common yards.
Before reaching for antibiotics and miticides, beekeepers should consider trying some alternative control tactics. For example, if a colony has American foulbrood, all the adult bees can be shaken off the combs that contain diseased brood and highly contagious spores, and the bees can be introduced into a new colony, on brand new combs. A new queen, one preferably bred for hygienic behavior, can be introduced into the new colony, and the colony can be fed sugar syrup until the disease spores the adult bees may be carrying are flushed through the system. By the time the new queen is laying eggs, the disease spores will be essentially eliminated, and the colony can continue on, disease free.
There are also methods that can be used to reduce mite levels. The best one is trapping the mites in drone brood. Because Varroa prefers to parasitize drone brood, a colony can be encouraged to rear drones by giving them combs with drone-sized brood cells. When the drones are pupating and full of mites, the combs can be removed from the colony and frozen until the drone pupae and mites die. If this process is repeated continuously over a summer, mite levels can be reduced considerably.
Good bee nutrition may serve both as a solid preventative and as a control. More research is needed on the link between good bee nutrition and resistance to diseases and parasites!
A goal in beekeeping should be to put chemical controls in last place, both in mind and in practice. Chemicals should only be used as a last resort, with great reluctance and restraint. Beekeepers should think, and think again, before applying antibiotics and miticides to bee colonies. There are now mite treatments based on the essential oil thymol or on organic acids such as formic and oxalic acid. They are relatively effective and if used properly will not lead to mite resistance nearly as fast as other pesticide treatments.
Knowledge. Prevention. Control. To keep bees healthy, spend the most time on the first two steps, which will enable you to eliminate or reduce the amount of time on the last step. Use control measures such as antibiotics and pesticides only as a last resort.