État des lieux du phénomène de dépérissement des ruchers en Région wallonne

Abstract

Since 1999 a growing number of beekeepers in the Walloon Region have been reporting an unusual decline in their bee colonies. The origin of the decline is not known. This work has provided for the first time a list of all beekeepers in the Walloon Region. Three types of investigation among the beekeepers have shown that 30 % of all apiaries were affected by the decline during the winter and spring of 2003-2004. Moreover, 15 % of the colonies died and 16 % were considered unusually weak. Maps were designed and showed the presence of the decline in all areas of the Walloon Region. An analysis of all results showed that bee colonies are more likely to decline in an agricultural environment. No relation between the varroa treatments or level of infestation could be put forward. The symptoms of the recent bee decline are also different from all known bee diseases. We suggest a long term follow up of selected apiaries, a more thorough investigation of the plants visited by bee colonies and a systematic analysis of pesticide residues in those plants.