Final diagnosis


Various oomycetes (damping-off, root rots)

The entire root system of this lettuce is dark brown in color. <b> <i> Pythium </i> sp. </b> ("damping-off")
Several leaves of this salad show wide moist patches, soft in consistency and dark brown in color. In some places, the fabrics have melted. A rot is progressing in the heart of the apple. <b> <i> Pythium </i> sp. </b> ("<i> Pythium </i> diseases")
Round, thick-walled oospores are present on or in root tissues; they frequently materialize the parasitism of <b> <i> Pythium </i> spp. </b> ("damping-off").
Observation under a photonic microscope often makes it possible to observe the presence of structures characteristic of <i> Pythium </i>: mycelium, oogonia (ornamented in this case), sporangia. <b> <i> Pythium </i> sp. </b> ("damping-off")
Swollen filamentous sporangium of <b> <i> Pythium aphanidermatum </i> </b> ("damping-off")
Filamentous sporangium of <b> <i> Pythium </i> sp. </b> ("damping-off")
Globular sporangium of <b> <i> Pythium </i> sp. </b> ("damping-off")
Aquatic oomycetes produce flagellated <b> zoospores </b> from sporangia during asexual reproduction, thus allowing the pathogen to spread.
Smooth oogonium fertilized by an antheridium, intercalary hyphal swelling. <b> <i> Pythium </i> sp. </b> ("damping-off")
Oogonia ornamented with <b> <i> Pythium </i> sp. </b> ("damping-off")