Colonization of wheat seedling leaves by Fusarium species as observed in growth chambers: a role as inoculum for head blight infection?

► Fusarium spp. do not directly penetrate wheat leaf tissue after conidia germination. ► Some Fusarium spp. form runner hyphae underneath the cuticular layer. ► Inside leaf tissues, hyphae thicken in diameter and are both inter-and intra-cellular. ► Infection and colonization of wheat tissues is asymptomatic in some cases. ► Incubation of senescing wheat leaves at 100 % relative humidity results in sporulation of Fusarium spp.