2.4.4. Disease control
- “High quality” of queens means also that they are free from pests and diseases (Laidlaw, 1979; Cobey, 2007). Therefore special care has to be taken in order that the productive colonies as well as the mating nuclei show no signs of contaminating diseases such as foulbrood and nosema. Methods for reducing pest/pathogen loads in colonies can be found in the COLOSS BEEBOOK papers on honey bee diseases (De Graaf et al., 2013; De Miranda et al., 2013; Dietemann et al., 2013; Forsgren et al., 2013; Fries et al., 2013; Jensen et al., 2013). One way to ensure that the produced queens are free from nosema spores is to count the number of spores in the alimentary canal on the same sample of queens sacrificed for the other characteristics mentioned above (number of ovarioles, diameter of spermatheca, and number of spermatozoa). According to Rhodes and Somerville (2003), this number should be less than 500,000 spores per queen. However, the queen’s attendants in the queen cages can also transmit nosema spores to the queens or to the receiving colony, but the threshold for the accepted limit has still to be evaluated.