Infection incidence, kernel colonisation, and mycotoxin accumulation in durum wheat inoculated with Fusarium sporotrichioides, F-langsethiae or F-poae at different growth stages

A 2-year field experiment was conducted to determine the effects of Fusarium sporotrichioides, F. langsethiae, or F. poae on durum wheat plants artificially inoculated at different growth stages. The percentage of symptomatic kernels was similar among the three species, but incidence of infected kernels was lower for F. langsethiae. Kernel colonization was higher when plants were inoculated before and during anthesis for F. sporotrichioides and F. poae, but unaffected by timing of inoculation for F. langsethiae. Production of T-2/HT-2 toxins was higher for F. sporotrichioides than for F. langsethiae. Significant accumulations of nivalenol were detected for F. poae. Across all three species, there was a weak correlation (r=0.16; P=0.031) between the incidences of symptomatic and infected kernels, but a stronger correlation (r=0.53; P<0.001) between infection incidence and the quantity of fungal DNA (species-specific) in kernels. Mycotoxin content was correlated (r>0.58; P<0.007) with infection incidence or fungal DNA in kernels, but only for F. sporotrichioides and F. poae.