Biology and Epidemiology

- Conservation and sources of inoculum

Olpidium brassicae produces "resting spores" or chlamydospores which ensure its conservation for several years in the soil and on plant debris (figure 1). It can also survive on several hosts.
 

- Penetration into the plant and invasion

Contamination occurs through uniflagella zoospores, produced by resting spores or sporangia. They are attracted to host roots, encyst on the surface, and then penetrate directly into cells. In there the fungus produces one or more aggregated sporangia which form zoospores thus ensuring the secondary contamination.


- Dissemination of the pathogen

Zoospores are released outside the root cells through the exit tubes. Once in the aqueous phase of soil or in the nutrient solution, a flagellum allows them to move and spread to other plants. Olpidium brassicae is probably spread by dust from soil, plants and contaminated water.

- Favourable conditions for fungus development

Olpidium brassicae is perfectly adapted to aquatic life and it is spreading quickly in hydroponic crops. It grows well at temperatures between 10 and 16 ° C.