Ask the Expert: Black Hive Boxes and Comb
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Chris W. asks:
My boxes look black, as do the combs that go in the boxes. Is this normal?
Rusty Burlew replies:
Within a winter hive, it is common to find unpainted woodenware that has turned black. The dreary color results from various molds and fungi that thrive in the warm, damp environment.
Although it is relatively harmless to bees, black mold usually means interior moisture levels are too high. In the cold months, moisture accumulates inside the hive because of bee respiration. The bees’ breath is warm, so it rises to the top of the hive where it condenses on cold interior surfaces such as the box walls or the tops and ends of wooden frames. Molds, which love damp and dark surroundings, can thrive on these spongy surfaces, eventually turning the wood black.
Beekeepers deal with excess moisture in a variety of ways, depending on how cold the outside air becomes. Some like to add more ventilation at the top so the damp air can escape before it condenses. Others like to add moisture quilts that trap the moisture in an absorbent medium such as wood chips or burlap.
While it is tempting to keep honeybees as warm as possible, moisture is more detrimental to bee health than cold. A colony of dry bees can keep itself warm, but a colony of wet bees will suffer. Your dark frames are a warning sign that your bees may be too wet.