The Agronomists, Ep 75: White mould and sclerotinia management with David Kaminski and Rob Miller
by RealAgriculture Agronomy Team
White mould of soybeans, dry beans and sunflowers is the same disease as sclerotinia of canola and sunflowers. What’s more, it’s a disease that can infect a multitude of broadleaf weeds. The endemic nature and soil survivability of the pathogen make it a tough disease to keep on top of.
To tackle management of this disease, we go to David Kaminiski, plant pathologist with Manitoba Agriculture, and Rob Miller, technical development manager with BASF.
This episode of The Agronomists is brought to you by ADAMA Canada, the Mind Your Farm Business podcast, and our July 19th webinar on infrastructure investment (register here).
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Ontario could use a rain; Manitoba doesn’t need it, thanks
We’re talking sclerotinia/white mould. Fun fact, it’s the same pathogen! And it isn’t terribly picky on what crop it lives on. Most broadleaf crops are a host
Plenty of weeds are too, Miller adds. Good weed control matters.
Is it dry beans or edible beans? You decide.
White mould/sclerotinia is difficult to control for several reasons, including the length of time the resting bodies (sclerotia) can live in the soil, even in dry conditions
Tillage can bring new sclerotia to the surface
You’re looking for small mushroom like structures — but don’t confuse the apothecia (the wee mushroom) with bird’s nest fungi!
Management is key: rotation, row spacing, plant populations, but also, when the risk is high, you’ve got to protect the flower petals, regardless of the crop
Ideal timing on soybeans is R1.5 to R2
The disease is likely always present, but that doesn’t mean the environment or field conditions are conducive to disease development — a spray is not a foregone conclusion
It depends on the year, depends on the field, and the field history
No-till lowers risk
Higher plant population and tighter rows equals more risk (think air movement in the canopy)
Manage the crop, not the weather
In July, if the grass is green, white mold is keen! Grass is brown, white mold is down
Sclerotia do die in the soil. What about other soil pathogens and fungi that feed on sclerotia? So do we have some biological help in the fields? There is some
Trying to find apothecia? Look on canola stubble, sunflower stubble
Chuffing ascospores (Lyndsey’s new band name) really project the spores — which means they can blow in from some distance away
Pop quiz: do dry conditions automatically mean a dialling back of nitrogen rates on corn? This is a tricky question to answer as very dry conditions for prolonged periods can impact yield potential, but dry conditions also mean nitrogen is less available to the plant, so it's a tough call. For the answer to why…
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