ABSTRACT
Fluctuating temperatures incite chalkbrood disease (Ascosphaera apis) in honey bee colonies. This chapter describes a novel technique for estimating the temperature where the incidence of chalkbrood is the highest, which may vary according to species. In the laboratory, growth rates for pure fungal isolates of A. apis were determined by measuring the spread of the mycelium in a Petri dish at different temperatures. Graphical analysis shows there is a critical transition temperature (CTT) where a rapid increase in growth rate occurs. CTT of A. apis matches the temperature where chalk-brood symptoms are seen. Thus, determination of CTT can be an effective tool for gauging the onset (and offset) of a fungal disease.
