Much research has been conducted to develop biological controls from this observation. Current control measures, however, are still based primarily on rotation. Inoculum source for Group II isolates is infected corn debris Infection is associated with flowering and high humidity F. culmorum is the pathogen in cooler climates such as Europe. This is especialy a problem if one is trying to compare data from papers published 30 or 40 years ago with more recent literature. Macroconidia are canoe shaped, have 3-5 septa, and are produced on sporodochia.
Chlamydospores are thick-walled spores formed by rounding up of hyphal or macroconidial cells.
Chlamydospores are particularly resistant to dessication and extremes of environment, and therefore act as overwintering propagules. All six species mentioned above form chlamydospores, however, chlamydospores of F. graminearum are short-lived in soil and survive only in debris. I occurs in the Pac. N'west on wheat, other small grasses primarily as foot and crown rots. Group II causes stalk rot of corn and scab of wheat in Midwest.