Pandora neoaphidis and Entomophthora planchoniana are
widespread and important specialist fungal pathogens of
aphids in cereals (Sitobion avenae and Rhopalosiphum padi).
The two aphid species share these pathogens and we compare
factors influencing susceptibility and resistance. Among
factors that may influence susceptibility and resistance are
aphid behavior, conspecific versus heterospecific host, aphid
morph, life cycle, and presence of protective endosymbionts. It
seems that the conspecific host is more susceptible (less
resistant) than the heterospecific host, and alates are more
susceptible than apterae. We conceptualize the findings in a
diagram showing possible transmission in field situations and
we pinpoint where there are knowledge gaps.