Valuable evidence about the safety of plant protection products comes from monitoring approaches where potential effects of the products under investigation are surveyed under realistic field conditions as resulting from uses in agronomic practice. In contrast to laboratory or other, possibly lower-tier results, monitoring data have the advantage that they provide insight into what happens in reality and do not require any extrapolation approaches which may bring in insecurities in the assessment.
Monitoring shows practical conditions as they are; therefore the observation level is a different one than in ecotoxicological effect studies – observations are less detailed as for instance in field studies, but in turn, a much larger set of observations is included. There are active and passive monitoring systems The former are based on field surveys to assess whether a certain use sets any damage to the observed organism, the latter do more or less systematically record incidences of damage caused by products wherever they are observed.
There are monitoring systems in place in many European countries, which are either specifically dedicated to detect effects of pesticides to bees, or that include assessments that provide important information about potential correlations between the use of pesticides and damage to bee colonies.
An example is for instance the German Bee Monitoring that has been started in 2004. In this monitoring program, more than 1000 bee colonies in all parts of the country are intensively surveyed and observed over many years. In the scope of these surveillance activities, all factors are assessed that might influence the health of the colonies, e. g. diseases, parasites, but also exposure to pesticide residues, among them neonicotinoids, and to neonicotinoid-treated cultures.
The results clearly demonstrate that there is no correlation between exposure of bee colonies to in-hive residues of pesticides and colony mortality. Likewise, no correlation was found between colony mortality and exposure to crops which are intensively treated with pesticides, for instance oilseed rape. Similar results were found in comparable monitoring approaches in many countries, for instance France, Belgium, Austria, Switzerland, Spain, and the US.