Fusarium on french garlic, etiology and characterization of an emerging disease
Résumé
Background: Yearly, France produces more than 20000 tons of garlic representing 3500 producers
and 3000 ha. Since the mid-2000s and in spite of high demanding production specifications, a
phytopathogenic fungus belonging to genus Fusarium, causes damage during storage leading to root
and bulb rots. The annual losses have a major impact on the viability of the French industry.
Objectives: Two major objectives were to :
• Elucidate the etiology of the disease on garlic
• Develop a test to evaluate the aggressiveness of strains
Methods: Strains were isolated from the two major French production areas (South West and South
East) during the 2017 and 2018 production campaigns. Eleven garlic varieties on more than 90 plots
were used. All tested cloves were surface-sterilized with NaOCl and fungi were allowed to develop on
PDA.
To evaluate aggressiveness of each strain, twelve surface-sterilized cloves soaked in 1.0*106
spores/mL were used. All cloves were placed separately at 23°C at saturated humidity for 18 days.
Symptoms were noted with rating scale from 0 (absence of symptoms) to 5 (clove entirely brown).
Every 2 days, Area Under the Disease Progress Curve was calculated for each clove.
Results: In total, 1580 strains were successfully isolated, 262 identified (98% F. proliferatum and 2%
F. oxysporum) and 48 tested for their aggressiveness. All varieties seemed to be infected equally,
some plots more than the others. All tested strains shows aggressiveness on garlic, from 60 to 140%
as compared to a reference strain.
Format : Poster