EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
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SESSION 3: PATHOGENESIS – EPIDEMIOLOGY AND POPULATION<br />
GENETICS<br />
Dynamic <strong>of</strong> production and maturation <strong>of</strong> Gibberella<br />
zeae perithecia on crop debris<br />
V. Manstretta 1 , E. Gourdain 2 , V. Rossi 1<br />
1 Instituto di Entomologia e Patologia vegetale, Università Cattolica del Sacro Cuore, via Emilia<br />
Parmense 84, 29122 Piacenza, Italy; 2 Service Qualités-Valorisations, ARVALIS - Institut du végétal,<br />
Station Expérimentale, 91720 Boigneville, France<br />
E-mail: valentina.manstretta@unicatt.it<br />
Gibberella zeae (anamorph Fusarium graminearum) is a key species <strong>of</strong> Fusarium<br />
head blight and consequent mycotoxin accumulation in wheat grain. G. zeae<br />
produces inoculum on residues <strong>of</strong> the previous crops. The dynamic <strong>of</strong> perithecia<br />
production and maturation were studied in controlled conditions and in the field, to<br />
acquire information on ascospore dynamics during the season.<br />
Maize stalks inoculated with G. zeae were incubated at different temperatures (5<br />
to 40°C) at 100% relative humidity (RH). Numbers and maturity class <strong>of</strong> perithecia<br />
were assessed once a week over 8 weeks. Perithecia were produced between 10<br />
and 30°C. At optimum temperatures (20, 25°C), perithecia emerged after 7 days<br />
<strong>of</strong> incubation. Perithecia matured only at optimum temperatures, from 14 days <strong>of</strong><br />
incubation onwards.<br />
Inoculated maize stalks were also incubated at 25°C between 62.5% and 100%<br />
RH, which correspond to 15 to 80% moisture <strong>of</strong> the stalks. Perithecia were<br />
produced at RH 75% and reached the maximum number at 100%. Perithecia<br />
matured only with RH85%.<br />
Studies were performed on different crops residues, inoculated and incubated at<br />
20°C at 80% RH for 3 weeks. Perithecia were produced on all tested debris;<br />
emergence started after 9 days on rape, sugar beet and potato, which had the<br />
highest production, compared to wheat, maize, pea and sunflower.<br />
Infested stalks were exposed outside between March and July over two years, in<br />
three groups: i) always wet trough contact with a wet substrate, ii) kept dry by a<br />
protection from rain, iii) left in natural conditions. Perithecia dynamics were<br />
assessed twice a week. More perithecia and more rapid maturation occurred in<br />
the wet residues, while no perithecia were produced in the dry one. More<br />
perithecia were produced in the year with more rain.<br />
In conclusion, temperature, moisture and kind <strong>of</strong> residue influence the dynamic <strong>of</strong><br />
perithecia production and maturation.<br />
Keywords: Gibberella zeae, crop debris, temperature, moisture<br />
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