Honeybee mortality in Europe less common than expected
The study was implemented in 2012 - 2013, with the participation of 17 Member States. Three visits were made to each randomly selected apiary: first before and after wintering and then during the beekeeping season. The number of apiaries sampled varied by country: in all, 3,284 apiaries and 31,832 colonies were visited. The Finnish sample of 161 apiaries and 787 colonies targeted five areas: Åland, Jokioinen, Seinäjoki, Kitee and Kajaani, along with their adjacent municipalities.
Overwintering mortality rate by country ranged from 3.5% to 34%. In Finland, the overwintering mortality rate was 23%. The particularly cold winter of 2012 - 2013 in the study period was demanding for honeybee colony survival. During the beekeeping season of summer 2013, the mortality rate of honeybee colonies in Finland was 7%, whereas in the other countries surveyed the rates varied from 0.3% to 14%. In country comparison, Finland had the fifth highest mortality rate. Before the present study, there had been no previous systematic research or published paper on colony losses during the beekeeping season in Finland.
New information on the prevalence of American foulbrood
Apart from assessing apiary husbandry practices and the health status of colonies, the study sought to determine the prevalence of pathogens through samples taken in connection with the visits.
American foulbrood, a common honeybee disease, was observed in 3% of the Finnish sample apiaries. In six Member States, the prevalence was below 3%, and in the others it varied up to 12%. This means that in European disease comparison Finland is situated roughly in the middle.
“The American foulbrood situation was believed to be significantly worse in Finland than in other countries. This misconception was partially due to the sensitive detection method employed in Finland, namely microbial culture of honey. In many countries, diagnosis is based solely on clinical findings of larvae deformities in infected colonies,” says Researcher Sirpa Heinikainen, Veterinary Bacteriology Research Unit.
Finland was the only participating country to conduct an additional analysis of honey from sample colonies for the presence of Paenibacillus larvae spores. This was to determine the geographical distribution of the disease. Spores were detected in about 30% of the apiaries, i.e. the presence of spores was ten times more common than the disease itself. There was great variation across the target areas, with Jokioinen and Seinäjoki having the highest number of incidences. The EU study indicates that the disease is controllable by means of systematic preventive action to ensure, among others, that Paenibacillus larvae spores are absent in any colony offered for sale.
Researcher Sirpa Heinikainen, Veterinary Bacteriology Research Unit, tel. +358 44 720 1780