What is primarily affected by European foulbrood in a bee colony?

European foulbrood primarily impacts the larvae of honey bees. This bacterial disease, caused by Melissococcus plutonius, manifests in the brood, specifically affecting the developing larvae. Infected larvae exhibit symptoms such as a slimy, yellowish appearance and often die before they can pupate, leading to significant losses in the brood population.

While the adult worker population may eventually be affected due to the reduced number of new bees emerging from the brood, the immediate and most devastating impact is seen during the larval stage. The queen bee's laying capacity may also be indirectly influenced, but the primary concern lies with the health and viability of the larvae. Honey production rates may be impacted as a consequence of the overall health of the colony, yet the focal point of European foulbrood is the larvae that have become infected.