Three days after contacting a capilliconidium (secondary spore) the aphid dies and the fungus produces thousands of explosively discharged  primary conidia.  All stages of the cotton aphid (apterae, alatae, and immatures) are attatcked by N. fresenii . After the aphid dies, its body is quickly consumed by sapropytic fungi.

Aphids killed by N. fresenii remain on the leaf, anchored by their mouthparts.  Their bodies point upward, aiding the dispersal of spores. Cotton aphid sporulating.  Coniophores  are visible extending through the integument. Alate cotton aphid covered with primary and secondary conidia. Explosively discharged primary conidia of  N. fresenii.