Bees for Development Journal 110
PRACTICAL BEEKEEPING
GOOD BEEKEEPING PRACTICE –
HOW TO FOSTER SELF HEALING Wolfgang Ritter, CVUA-Freiburg, Am Moosweiher 2, D 79108 Freiburg, Germany PHOTO © SCHWENKEL
Keywords: American foulbrood, chalkbrood, European foulbrood, hygienic behaviour, sacbrood, Varroa The fourth in the series from Dr Wolfang Ritter offering advice for Good Beekeeping Practice to ensure healthy honey bees.
How to support brood control by workers In brood rearing, a honey bee colony not only balances the removal of old and ill bees, it also influences the total number of bees, ie the weight of the colony. To ensure that the colony consists of resistant and long-living bees, only healthy brood should be reared. Therefore, bees constantly inspect their brood: ill parts are removed, healthy parts are maintained and eventually open cells are sealed again. This hygienic behaviour by the bees is part of the self-healing capacity of the colony. This self-healing capacity has been employed for some time in bee breeding to select Varroa tolerant bees. However, depending on the type of brood disease, the requirements concerning hygienic behaviour are quite different: for example with the Varroa mite, it is less important when the bees inspect the cells. However foulbrood, chalkbrood and sacbrood can be controlled only if they are recognised by the bees before the brood is infected. Otherwise the disease is spread through the colony anyd matters get worse.
When inspecting colonies pay special attention to irregularly occupied brood cells year, becomes ill – chalkbrood and sacbrood mostly appear first – and consequent requeening is the only solution. But in most cases it is more difficult to judge and decide. Quite a lot of management conditions and interventions by the beekeeper influence hygienic behaviour.
Genetics decide The Alpha and Omega of hygienic behaviour is the genetic predisposition of the honey bee colony. When brood in nucleus colonies with queens of a certain breeding series, or of the same
Food stimulates cleaning up
PHOTO © YVES LE CONTE
When bees gather aqueous nectar or honeydew, they have to empty any available cell for interim storage. Many bees work through the cells, with crowds of inspecting and cleaning bees on their way to remove everything objectionable. Especially obstinate brood diseases like chalkbrood and sacbrood can be made to disappear this way. If you cannot offer adequate forage for your bees you should feed them with a thin sugar or, even better, a thin honey solution. You can also spray the solution on to the combs to instantly stimulate hygienic behaviour.
Alleviation of infection pressure If and how quickly the bee colony can heal itself depends mainly on the scale of cleaning activities. Here the beekeeper’s support is required. It is recommended that combs with predominantly ill brood are melted or disposed of. How many combs should be removed depends mainly on the colony’s condition and the season. A strong colony will quickly recover from the loss of part of its brood, especially during periods of growth. You can also take a more radical decision and remove all combs. Then the open artificial swarm allows sanitation even in the case of American foulbrood.
Adaption of space to colony strength Hygienic behaviour is not restricted to just the brood, but applies to the whole nest. Bees busy cleaning other parts of the nest are not available in the brood area which is the place most at risk. Mouldy combs at the periphery are an alarm signal indicating that the colony is overcharged. Therefore, the space should always be adapted to the colony strength. In some hives with combs in one box - for example in top-bar hives - the brood nest can be defined
In the Varroa tolerant bee colonies observed by Yves le Conte, the bees keep cells with pupae open in order to kill the Varroa mite offspring. The colonies from which this comb originates have survived for seven years without treatment – at Avignon in France 3
