MELISSA - Report
The number of reports about honey bee colony losses or damages from many countries has increased over the last years. The potential causes are numerous and could differ case by case. According to the current knowledge, a single factor is rarely responsible. In fact, in many cases more likely a combination of etiological factors is involved, e.g. colony management and good apicultural practice, environmental and anthropogenic elements as well as honey bee pests and parasites.
In spring 2008 severe honey bee losses occurred in Germany (Rhine valley), in Italy and Slovenia during and after sowing of clothianidin coated maize seed with pneumatic seed drills. Further investigations in Germany proved the causal connection between the use of this seed dressing insecticide and the reported damages in honey bee colonies.
In order to assess the possible relevance of this problem to Austria, the project “Investigations in the incidence of bee losses in corn and oilseed rape growing areas of Austria and possible correlations with bee diseases and the use of insecticidal plant protection products” (acronym: “MELISSA”) was carried out in the years 2009 – 2011 on behalf of the Federal Ministry of Agriculture, Forestry, Environment and Water Management and the Austrian federal provinces. The aim of the project was to identify possible correlations between the incidence of honey bee losses in production areas of maize and oilseed rape and bee diseases or the use of plant protection products on the basis of field data.
Summing up, the results of the MELISSA-project give evidence that in Austria regional clustered bee damages had occurred in the years 2009 – 2011, which were frequently associated with the use of maize and oilseed pumpkin seeds coated with insecticides, as proved by residue analysis. The strong local component and the accumulation in areas with small-scale structured agriculture indicated special environmental conditions resulting in an increased exposition of honey bees to the identified insecticidal plant protection substances in the affected areas.
Regulatory measures to prevent honey bee losses due to the exposure of bees to insecticidal seed dressing substances have significantly improved the situation. However, repeatedly observed incidences of honey bee mortality in defined regions suggest their systematic correlation with local factors contributing to increased exposure of bees. In addition to considering environmental factors, all measures to mitigate risks have to be implemented invariably and with discipline.