Fusarium culmorum: Infection process, mechanisms of mycotoxin production and their role in pathogenesis in wheat

Fusarium culmorum is an important pathogen of wheat causing seedling blight, foot rot, and head blight (Fusarium head blight (FHB)) or scab. The pathogen is dominant in cooler areas like north, central and western Europe. The fungus reproduces asexually by means of conidia, which form the main mode of dispersal. Head blight is by far the most serious concern of Fusarium infection on pre-harvest wheat and other small grain cereals. The significance of F. culmorum in wheat production is attributed to both head blight and mycotoxin contamination of the grain harvested from infected ears. Ear infection mainly occurs during anthesis and is favoured by wet weather or high humidity and warm temperatures. The major mycotoxins produced by F. culmorum are deoxynivalenol, nivalenol and zearalenone, which are a potential health hazard for both humans and animals. The mycotoxins, especially deoxynivalenol, are believed to play a role in disease development. Available options of managing FHB include use of fungicides, cultural practices, resistant cultivars and biological agents. However, no wheat cultivar is completely resistant to FHB while fungicides are at most 70% effective against natural infection. This review seeks to document and infer information on F. culmorum, with special emphasis on wheat head blight infection process, mechanisms of mycotoxin production, the role the mycotoxins play in pathogenesis, and the possible management options.