1.5.2. Infection bioassay of colonies
When it is necessary to provoke chalkbrood infection in bee colonies, it may be sufficient to infect a group of larvae, or it may be necessary to cause widespread disease in the colony. The procedure differs for each case. In the first case, the larvae are directly fed spore-contaminated food. In the second case, the entire colony is exposed to spores either by spraying, feeding sugar/honey with spores or feeding pollen patties with spores (Moffett et al., 1978; Flores et al., 2004a). Flores et al. (2004a) evaluated different ways to inoculate colonies with A. apis spores using pieces of comb containing bee brood that have been subjected to controlled chilling. A mummification of 90.63 % of the brood was reached by spraying water containing spores over combs, and colonies fed spore-pollen mixtures reached 86.32 % infection. The use of sugar syrup with spores only reached 60.13 % mummification and proved to be less effective. We recommend spraying or feeding inoculated pollen since these methods have proven to be most effective.