EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
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SESSION 5: DISEASE CONTROL AND FORECASTING MODELS<br />
P124 - Saprophytic survival <strong>of</strong> Fusarium graminearum<br />
in crop residues<br />
J. Leplat 1 , L. Falchetto 2 , P. Mangin 2 , C. Heraud 1 , E. Gautheron 1 , N.<br />
Gautheron 1 , V. Edel-Hermann 1 , C. Steinberg 1<br />
1 INRA, UMR1347 Agroécologie 17 rue Sully, BP 86510, F-21000 Dijon, France; 2 INRA, UE Domaine<br />
d’Epoisses, F-21110 Bretenières, France<br />
Email: christian.steinberg@dijon.inra.fr<br />
Fusarium Head Blight (FHB) is one <strong>of</strong> the most important disease altering wheat<br />
crops. A field experiment was conducted to better understand the saprotrophic<br />
development <strong>of</strong> Fusarium graminearum and its consequences on FHB, to<br />
characterize the relative importance <strong>of</strong> the different sources <strong>of</strong> FHB inoculum and<br />
the accumulation <strong>of</strong> mycotoxins in grains and subsequently, to determine early<br />
indicators <strong>of</strong> future disease development on ears and accumulation <strong>of</strong> mycotoxins<br />
in grains. The development <strong>of</strong> F. graminearum in the soil and crop residues was<br />
monitored in controlled conditions.<br />
The inoculum hosted by seeds and/or buried with crop residues in the topsoil had<br />
only an effect on the winter development <strong>of</strong> the disease. In contrast, the main<br />
source <strong>of</strong> inoculum causing FHB disease on ears and accumulation <strong>of</strong> mycotoxins<br />
in wheat kernels came from residues left on the soil surface. Monitoring <strong>of</strong> plant<br />
development from sowing to harvest, crop management and soil and weather<br />
conditions produced a large database. Unfortunately, the role <strong>of</strong> climate was<br />
decisive in the development <strong>of</strong> the Fusarium-host plant interaction, thus prevented<br />
the use <strong>of</strong> early indicators to accurately predict the risks <strong>of</strong> yield losses and<br />
accumulation <strong>of</strong> mycotoxins involved.<br />
F. graminearum was regulated by the soil micr<strong>of</strong>lora. However, crop residues<br />
provide the fungus spatial and trophic niches favourable to its development. The<br />
exploitation <strong>of</strong> these niches by F. graminearum depends on the nature (previous<br />
crop and C/N) <strong>of</strong> the residues. Maize stubbles provide a greater carrying capacity<br />
than wheat straw and rapeseed residues while mustard has a suppressive effect<br />
for the fungus.<br />
The management <strong>of</strong> crop residues is a key point to control the development <strong>of</strong><br />
FHB. A strong emphasis should be placed on the biological decomposition <strong>of</strong> crop<br />
residues at the soil surface or/and on the use <strong>of</strong> suppressive intermediate crops<br />
such as mustard to limit the soil inoculum potential <strong>of</strong> saprotrophic F.<br />
graminearum.<br />
Keywords: early indicators, ecological niche, epidemiology, conservatoire<br />
biological control<br />
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