Hygienic Behaviour: An Alternative to Synthetic Chemicals in the Control of Honey Bee Brood Diseases

​Commentary
​Beekeepers use various methods to control honey bee brood diseases. These include antibiotics, for example tetracycline in the control of American foulbrood (AFB), and acaricides, such as fluvalinate (the active ingredient in Apistan strips) to control varroa mites.
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One advantage of hygienic behaviour is that it can reduce the need for synthetic chemicals. In much of the USA AFB is common and beekeepers often treat their hives with antibiotics as a preventive measure. (Some beekeepers also attempt to “cure” hives of AFB although this is not advised as it will not kill any AFB spores.) Antibiotics and acaricides can be applied in a way that does not contaminate the honey that will be harvested for human consumption, such as by treating before the honey supers are placed on the hives in spring or after they have been removed in late summer. However, some beekeepers may prefer not to put synthetic chemicals in their hives and some customers may prefer not to purchase honey from treated hives.
 
Resistance is a major shortcoming of antibiotics and pesticides. Varroa resistant to fluvalinate are widespread as are strains of AFB resistant to tetracycline. Resistance is a general problem. Many human bacterial diseases show resistance to one or more antibiotics, and many insect pests in agriculture are resistant to one or more insecticides. Resistance is natural selection in action. Some mechanism of detoxifying the chemical arises as a new mutation and then becomes more common because it confers greater survival to the pest or pathogen. In principle, new chemicals can be developed to replace old ones for which resistance is widespread. In practice, alternative chemicals are limited in number and new chemicals are expensive to develop, test and register.   
 
A further advantage of hygienic behaviour is that it controls brood diseases for which there are no chemical controls. Chalkbrood is a disease I have had in my hives in New York, California, and England. It must be the most familiar of all honey bee diseases to most beekeepers, yet there is no registered chemical specifically to control chalkbrood. A disease of great current significance is deformed wing virus. It is vectored by varroa mites and can kill colonies, including via winter collapse. There is no chemical control for this disease either. Hygienic behaviour is highly effective against both chalkbrood and deformed wing virus, and also against American foulbrood.
 
© F. Ratnieks, May 2016