Biology, epidemiology

- Conservation, sources d'inoculum

Olpidium virulentus (eg Olpidium brassicae ) produces "resting spores" or chlamydospores which ensure its preservation for several years in the soil and on plant debris. It can also be maintained on several intermediate hosts given its polyphagia, in particular several vegetable species: tomato, cucumber


- Penetration, invasion:

Contaminations take place through uniflagellate zoospores originating from resting spores or sporangia (Figure 1). They are attracted to the roots, become encysted on their surface, then enter directly into the cells. The fungus produces one or more aggregated sporangia there which will generate zoospores ensuring secondary contamination.


- Dissemination

Zoospores are released outside the root cells through release tubes. Once in the water phase of the soil or in the nutrient solution, a flagellum allows them to move and reach other plants. Olpidium virulentus is certainly spread by soil dust, contaminated plants and circulating water.


- Conditions favorable to its development

This fungus is perfectly adapted to aquatic life and it quickly spreads in hydroponics. It grows very well at temperatures between 10 and 16 ° C.