Mode of Action
- The surviving structures (sclerotia) of Sclerotinia rot that persist in the upper soil layer germinate and produce mycelium in the soil. This infects the plants via the roots or via the stems or leaves near the soil line. Mycelium induced infection can occur at any time of the year and can appear just after planting a susceptible crop. Crops that mainly become infected due to mycelium growing in the soil: Chicory, Endive, Carrots, Lettuce and Sunflower.
- Sclerotia on or near the soil surface germinate to form fruiting bodies called apothecia (stalks with funnels on the end, like tiny mushrooms).
- The apothecia produce and eject ascospores which settle on dead or senescent parts of plants (petals, leaves, fruits and stems) where they germinate, provided that there is sufficient moisture. The pathogen establishes itself on these plants and advances on to healthy plant tissue. Crops that mainly get infected by spores: Aubergines, Beans and Soybeans Peas, Cucumber, Peppers (Red Chilli), Tomatoes, Watermelon, Lupine, Petunia and Oilseed rape (Canola).
- Regardless of the source of infection, white cotton wool-like mycelium spreads over the affected parts of the plant. Subsequently, black sclerotial bodies develop externally on affected plant parts and internally in stem pith cavities.
- The black sclerotial bodies reach the soil where they remain on the surface or become buried as a result of tilling practices, thus completing the life cycle of the fungus. The following crops are infected by both the mycelium growing in the soil and ascospores: Chrysanthemum, Celery, Sunflower and Tobacco.
Infection of host plants caused by mycelium growing in the soil
Infection of host plants caused by ascospores
Contans®WG interrupts the life cycle of Sclerotinia diseases. Its active agent Coniothyrium minitans attacks and destroys the sclerotia in the soil within two to three months.