The Influence of Different Forms of Nitrogen on Fusarium Root‐rot Disease of Winter Wheat Seedlings

Fusarium head blight: epidemiological origin of the effects of cultural practices on head blight attacks and the production of mycotoxins by Fusarium in wheat grains

“…Teich (1989) [90] suggested three hypotheses to account for this difference between urea and ammonium: i) the urea may decrease the size of the Fusarium population because nitrite blocks reproduction in these fungi and inhibits the formation of chlamydospores [124], ii) urea may prevent the maturation of Fusarium ascospores, as it does for those of Venturia inequalis [125], iii) urea may increase the number of actinomycetes in the soil [122,126], these microbes being antagonists of Fusarium graminearum [126] and F. oxysporum [122]. Furthermore, rotting of the base of the stem and of the roots is more severe if nitrogen is applied in an ammoniacal form than as nitrate [121,122,127]. This may also result from the higher rate of germination of F. solani (which may cause foot rot) in the presence of ammoniacal nitrogen than in the presence of nitrate [122].…”

“…This antagonism results from the fact that potassium increases nitrate absorption [122]. The nitrate absorbed activates nitrate reductase, leading to the accumulation of amino acids [127]. These amino acids are used in the synthesis of organic nitrogenous compounds [122] and of high-molecular weight compounds [103].…”

Influence of plant growth regulators and nitrogen on Fusarium head blight of wheat (Triticum aestivum L. Var. Kalysona)

“…Recent research in Quebec has focused on intensive cereal management through the use of nitrogen and growth regulators (Ayoub et al, 1994). Reports by Martin et al (1991) and Rowaished (1981) indicated that supplemental nitrogen and the plant growth regulator, ethephon increased the incidence of natural infection by F. graminearum in wheat cultivars. Others found that head blight and mycotoxin levels were not affected by the level of applied nitrogen but were greater when the preceeding crop was maize (Teich and Hamilton, 1985).…”