Chalkbrood is a serious fungal disease that kills honeybee larvae, caused by the fungus Ascosphaera apis. This study examined exactly how the infection progresses by infecting larvae in controlled laboratory conditions and observing them over time under a microscope. The researchers found that once infected, larvae die very quickly within 3-7 days as the fungus spreads throughout their bodies, and the fungus continues to grow even after the larvae are dead, eventually forming visible spores on the dead larvae that spread the disease to other bees in the colony.