Colony health

In principle, only colonies not showing disease signs should be included into the experiment. Then pathological signs, their date of appearance and severity should be noted (see BEEBOOK Volume II for information on this). The health status of the colony should be monitored from one week before the day the colonies are placed into the field and extended up to the overwintering. The appearance of pathological signs in the treatment colonies, but their absence in the control ones, could be due to a synergic effect pathogens-pesticide.