Mold in a beehive is a result of colony death, not the cause of it. Moisture in a winter hive comes mostly from the respiration of bees and from the decomposing bodies of dead bees. Surface mold may be common in combs other than those within a winter clusterwinter cluster:
a closely packed colony of bees forming in winter to conserve heat
position and in cells of stored bee bread outside of the cluster.
Mold quickly develops on dead bees (in cluster or on bottom board) and on cells of bee bread that are outside the cluster formation. Dead brood and the comb itself may have surface mold. Comb occupied by living bees will not have this mold.
Mold is removed as bees clean and polish beeswax cells in preparation for brood expansion. Comb from deadouts can be given to stronger colonies to remove and clean. Surface cleaning with soapy water or a dilute bleach solution might help prevent further growth of mold on deadout combs. Cull frames that are dark and aged.
Burlew R. 2017. Physics for beekeepers: mold in a beehive. Honey Bee Suite. Accessed 2023. https://www.honeybeesuite.com/physics-for-beekeepers-mold-in-a-beehive/
Veronica. 2022. How to Handle Moldy Bees and Hives. SWFBees. Accessed 2023. https://swfbees.com/moldy-bees/
“Beekeeping: Reusing Old, Moldy Comb”. YouTube, uploaded by David Burns, 19 May 2010. https://www.youtube.com/watch?v=Ad6m3vA_o6c
