126.96.36.199.2. Principle of the trial
Beehives come from a similar background, the same apiary or constituted in the same way. Their health status and strength are evaluated before the beginning of the trial. Then they are placed on the test fields as soon as the crop presents a number of flowers enough to allow the visit of foragers (5 to 15% of the flowers are flowering). The crop must have been treated at the time of seeding/planted when it starts to bloom. After the flowering period, the colonies are returned to a common area where they will remain until the following season.
The observation of effects continues during and after bloom. The monitoring can be extended until the spring of the following year. Especially when the tests is run during the period of production of winter bees, this monitoring until the spring becomes more relevant. Ideally, the generic observations on the full colonies should be complemented with individual tests studying the impact of sublethal doses on bees, e.g. homing flight tests or with more specific observations (fecundity, growth and development of individual honey bees), though many of the sublethal effects may be captured in the full colony assessments. .