1. Previous crop
Among the agents responsible for Fusarium head blight, F. graminearum is the most frequent one. Now, this fungi can also infect and survive on straw left on the ground after the crop, which decompose very slowly. A corn cultivated on the same parcel the previous year is thus very favorable to the development of Fusarium head blight in winter wheat given the importance of the inoculum presence on the ground and its potential inoculation. This phenomenon is much more important as the quantity of crop residues left on the ground.
2. Soil preparation
The soil preparation must be also considered. Indeed, the ploughing buries crop residues, and with them spores of fungis responsible for Fusarium head blight, what limits the development of the disease on the following crop. It is important to indicate here that this rule is not applicable any more for the second culture because in that case, the ploughing returns to the surface, insufficiently decomposed crop residues, which were buried during the first ploughing. A previous crop with corn associated to the absence of ploughing constitutes a major risk to the development of Fusarium head blight.
3. Crop variety
Several genes of resistance to Fusarium head blight were identified, and the use of resistant varieties is certainly a good perspective. However, given the multitude of factors which intervene in the development of the disease, the responser of varieties to the infection can be very variable from one year to another, what makes difficult the evaluation of the resistance for the head blight.
Based on observations realized for Belgian conditions, the rates of mycotoxins (DON) measured, during these last years in samples of grains allow to classify varieties in 3 groups: varieties for which the average rates of the DON are generally low (no value observed over 0,75mg/kg), varieties presenting an intermediate average rate of DON close to 0,75mg/kg and those who accumulate many DON (values systematically superior to 0,75 mg/kg when weather conditions are favorable.
4. Fungicide treatments
The evaluation of fungicide treatments on the mycotoxins production is difficult to establish because it depends on the Fusarium species involved in the development of the disease. Whatever is the agent of head blight or the used product, the disease control is more effective as the realization of the treatment is close to moment the most favorable to the infection, that is as stamens become visible. At this stage, it is nevertheless impossible to say with certainty, which is the Fusarium species dominating in the field.
When a fungicide treatment must be evaluated, it is for its specificity towards Fusarium species who may produce mycotoxins.
