Scientists at Agriculture and Agri-Food Canada are testing an early warning system for sclerotinia in canola. The project is in its first year and involves 35 volunteers in Saskatchewan monitoring the emergence of apothecia in 67 sclerotia depots across the province. Each depot consists of 50 sclerotia (fungal resting bodies) buried at the soil surface. Sclerotia in the depots are expected to germinate at a similar rate as the thousands of sclerotia naturally occurring in the soil (as a result of past sclerotinia white mould incidence). The volunteers report percent sclerotia germination two to three times per week when the canola is flowering. Sclerotia germination data from all depots are available on SaskCanola’s website (www.saskcanola.com). Click on the “Percent sclerotia germination map” icon. The provincial map can be moved in all directions and zoomed in or out.
How to use this information in your spray decision: The decision to apply a fungicide should be based on field-specific risk factors described in the sclerotinia stem rot checklist. The regional risk for apothecia development in the original checklist has been modified to “Percent sclerotia germination in a local depot”. 40 risk points, as suggested in the original checklist, is still the recommended threshold for applying a fungicide.
Want to help? Sclerotia depots are managed by volunteers primarily involved with extension work in the public or private sectors and a number of canola growers. If you are interested in managing a depot in canola next growing season please email firstname.lastname@example.org. Please let them know if you also are able to provide raw data (before statistical analysis) from a sclerotinia fungicide trial in canola nearby.
General page for sclerotia depots.
Early assessment of sclerotinia stem rot risk: While sclerotia in the depots have not started germinating, the fact many regions have good levels of moisture suggest a heightened risk at this point. Moist conditions in the two-week period before early flower will promote apothecia germination.