Brood diseases

Brood diseases affect honeybees in the larval and pupal stage. Although these diseases do not usually lead to the mortality of a colony, they can constrain its development. Bees can escape from brood disease by swarming and by actively abandoning the brood. If a beekeeper represses or disturbs these mechanisms, brood diseases can threaten the existence of the colony.

Bee colonies are affected by brood diseases resulting from bacteria, fungi, viruses and mites. Brood diseases impact the health of individual larvae and pupae, often resulting in mortality. Serious infections can affect much of the brood, which can ultimately slow the growth of a bee colony. Brood diseases can be exacerbated by poor conditions for bees, such as bad weather and lack of food.

Important bacterial diseases are American foulbrood (AFB) and European foulbrood (EFB). These brood diseases are extremely contagious and difficult to eradicate. Their control requires radical intervention by the beekeeper.

American foulbrood is a notifiable disease; a suspected outbreak must be reported to the competent authority. However, the government does not have the obligation to actually control the disease. This remains the task of the beekeepers.

Another important brood disease is chalkbrood. This fungal diseases changes infected larvae and pupae into mummies. It often occurs during long spells of wet and cold weather.

Bees@wur has prepared a number of documents and protocols with more background information about brood diseases and how they can be prevented and controlled.

If you have a suspected case of American foulbrood, then first read the plan of action: