Chalk brood has been studied quite extensively by Prof Len Heath and a series of PhD students at the University of Plymouth in the UK. He wrote about this in a rather broader context in the magazine BEEKEEPING last November. It is difficult to summarise but some points of interest are: hives in damp areas are not more susceptible; drone brood is not more susceptible; chilling brood is one of a number of physiological stresses which make larvae more susceptible; spores are almost everywhere where there are bees, they are fed to the larvae and may develop in the gut and grow through the body tissues; spores may or may not be formed depending on the conditions, but it is nothing to do with having two types of spores present; apart from the stress factor some bees are genetically more susceptible. I hope these points, based on research results, are of interest. Brian Gant Buckfast, UK Editor of BEEKEEPING