Abstract
Chalkbrood susceptibility levels were determined in selected Russian and domestic honey bee lines. A baseline chalkbrood infection level was first determined for each colony, followed by three chalkbrood inoculations, each one week apart. Chalkbrood mummies were counted one week after each inoculation and removed. Both Russian and domestic post-inoculation chalkbrood infection means increased an average of five fold when compared to the baseline infection level. However, the pre- and post-inoculation levels were not significantly different (P=0.13), probably due to the high number of colonies exhibiting 0% chalkbrood infection throughout the entire study. No significant differences in chalkbrood susceptibility were found between the two stocks (P=0.31), or between any lines (P=0.60). However, colonies showing extreme chalkbrood resistance or susceptibility were identified. They will be used as parents in a breeding study designed to study the genetic control of chalkbrood susceptibility.