The colonies should have queens of the same age (1-2 years) and from the same mother origin. Colonies should be homogeneous in size (adult bees and brood – Delaplane et al., 2013b), in brood composition (about same number of young and capped larvae) and in food supply among treatments. The colonies should be visited regularly, at least once or twice a week, for purposes of monitoring the health status and should be free of pathogens before the pesticide application (see Volume II of the BEEBOOK for methods to choose colonies that are free of the various pests/diseases). Each colony should have a bee population that covers at least 7 to 10 frames, containing at least: 5 brood frames, 2-3 frames of food, and 1-2 empty frames in order to allow colony growth. The hives should be placed in the edge of the field from 7 to 5 days before the application of the pesticide to the crop to allow the colony to adapt to the surroundings. In order to prevent the bees from foraging in another field, the installation of the hives should be made at the beginning of flowering and a minimum of 7 days before pesticide application. In order to consider the inter-colony variability, at least 10 hives equipped with dead bee traps should be installed in each field.