Many US beekeepers do not routinely replace their old combs. Older beekeeping books suggest that combs be reused to save money and energy that bees could use to make honey instead of wax. It is not unusual to find beekeepers who have combs that are over thirty years old.
In the wake of Colony Collapse Disorder, bee experts are recommending that combs be replaced more frequently. Dr. Marla Spivak of the University of Minnesota Department of Entomology recommends that comb should be replaced every 5-7 years. In Europe, it is recommended that combs be replaced every three years. In the UK, my beekeeping friends Emily Heath and Emma Sarah Tennant replace their combs annually.
Why the change? We now know that bees wax absorbs pesticides, both those used for treatment within the hive and those used in agriculture. Old combs may also retain disease spores, such as foulbrood and Nosema. American Foulbrood spores can remain viable in combs for as long as thirty-five years. Replacing combs may also be helpful in managing varroa mites.
It is easy to tell when comb needs replacing. It appears dark brown or even black in color. A good rule of thumb is to hold the frame up to the light. It should be replaced if light cannot be seen through it. The comb above looks very old.
There are three major ways to replace old comb: the Rotation Method, the Bailey Method and the Shook Swarm Technique.
The Rotation Method is the simplest, and the one I use. At the beginning of spring, when it is warm enough to separate the brood nest, remove the two outer frames from the box, which should be empty. Insert two new frames into the center of the box and move the frames left of center to the left and the frames right of center to the right. This will give you a full rotation every five years in a ten frame box.
In my next post, I will describe the Bailey Method and the Shook Swarm Technique.