[2] Ascosphaera aggregata is an obligate parasite[3] that causes chalkbrood in bees,[4] symptom manifestations differ depending on age of the larva.

[6] A. aggregata grows through the midgut wall to the hemocoele (event trigger is unknown, not because of lack of space nor food)[6] eventually replacing larval tissue.

;[6]) Ascospore development in A. aggregata is very unique and the resulting structure is referred to as a "spore cyst", or "ascocyst" or "synascus".

[8] Sexual development occurs on the outer mycelial mat in the subcuticular region,[3][6] and is documented to proceed as follows: Ascosphaera aggregata has been found to be unable to break down chitin.

[6][3] Although ascospore development is very unique, it is very hard to identify A. aggregata because the spore balls and conidia tend to resemble other species.