FUSARIUM HEAD BLIGHT AND DON CONTAMINATION MANAGEMENT IN SOFT AND DURUM WHEAT CULTIVATION - Soybean and Wheat Crops: Growth, Fertilization, and Yield - page 144

Full-factorial experiments that take into account tillage (tilled vs not tilled), wheat
cultivar (susceptible vs moderately resistant) and fungicide application (triazoles at heading
vs not treated) were conducted in naturally inoculated conditions in 4 sites in Italy during the
2006-2007 period.
The results were discussed taking into account some of the possible combinations of the
tested agricultural practices, representing different crop management systems classified for
the expected risk in FHB infection and DON contamination (Table 6), according to the
following scheme:

• HR: high risk agricultural practices, characterized by direct sowing of an untreated

highly susceptible cultivar;

• R: risk agricultural practices, with direct sowing of a highly susceptible cultivar,

treated with fungicide at heading;

• MR: medium-risk agricultural practices, with ploughing and cultivation of a highly

susceptible, untreated cultivar;

• RI: right agricultural practices, characterized by ploughing, a moderately resistant

cultivar and no fungicide application;

• CA: careful agricultural practices, in which a moderately resistant cultivar was sown

after ploughing and was treated with fungicide at heading.

The crop management systems showed significant differences as far as yield, incidence
and the severity of FHB, and DON contamination are concerned.
As expected, FHB severity decreased going from the higher risk crop management
system to the more careful ones. Compared to the HR treatment, the reduction in the severity
of FHB was 45, 43, 76 and 91% for R, MR, RI and CA, respectively. On the other hand, grain
yield generally increased with the application of crop management systems that are less
favourable to disease development.
The crop management system R reduced DON contamination by 60% compared to HR,
while a higher reduction was observed for both the MR and RI protocols. Compared to RI, a
further, not significant reduction, was observed with the fungicide application at heading
(CA).
If the data of DON contamination presented by Koch et al. (2006) are extrapolated, and
the agricultural practices in the same previously reported cropping systems are compared,
similar results can be obtained. Compared to the HR treatment, the head blight severity
reduction was 71, 80, 96 and 96% for R, MR, RI and CA, respectively.
These results underline that in years and environments with low FHB pressure the main
factors that contribute to heavy Fusarium infections of wheat crops are the presence of
residues of Fusarium -host crops on the soil surface and the cultivation of susceptible
cultivars. Moreover, no further significant reductions were observed with fungicide
applications at heading on a resistant wheat cultivar sown after ploughing.
Obst et al. (2000), in a four-year study in Germany, determined five FHB risk factors: (i)
maize as previous crop, (ii) minimum tillage after maize, (iii) use of a moderate or highly
susceptible wheat variety and (iv) application of strobilurin products. Again in this
experiment, the combination of these risk factors showed synergic effects: a single risk factor