Symposium contribution / Contribution à un symposium Epidemiology and biological control of Gibberella zeae / Fusarium graminearum

A decade of losses and damage due to fusarium head blight in cereals in North America and other parts of the world has resulted in great efforts to understand the factors that cause and intensify the disease. This review considers our current understanding of the importance of the contribution of cultural practices to the increase or decrease of inoculum levels, spore dispersal, and biological control of spore production and fusarium head blight. Perithecia of Gibberella zeae develop on aboveground residues, and on maize and wheat kernels rather than maize stems and wheat spikes, at temperatures of 15 and 25 °C, but not below 15 °C or above 30 °C. Ascospores are released during the evening, in response to rising relative humidity, and there is evidence for both local and longdistance dispersal. The effect of rotation and tillage system on the development of inoculum and FHB requires further research, but several studies indicate that weather may be the principal factor in development of the disease. Several fungal and bacterial species have been reported to inhibit hyphal and perithecial formation of G. zeae. These are discussed with an appraisal of the conditions and requirements to produce an effective biological control of G. zeae.