Chalkbrood is a fungus that enters hive through food. Once the brood is sealed in the cell, it will grow and kill the larva. Larva killed by Chalkbrood look a clear, whitish color. This infection can be identified by observing small chalk-like bodies on the ground in front of the hive
where worker bees have removed them too.
No successful treatment has been found as of yet, however, re-queening has been known to help otherwise the hive’s survival is hopeless.