The fungicides that assist in defending yield-robbing diseases like Sclerotinia in canola are only beneficial if they are applied before the symptoms appear. So how do you choose to spray or not? If you have the following three conditions, a foliar fungicide application is a smart choice.
- A strong and potentially high-yielding stand. A good-looking canola crop is probably worth protecting by any account. The fact that healthy stands provide the best conditions for Sclerotinia outbreaks further increases the importance of a fungicide treatment.
- Abundant moisture. If the canola field has high soil moisture, visible leaf moisture, high relative humidity in the crop canopy and/or the forecast calls for rain around the bloom stage, the scales are tipped in favour of a Sclerotinia infection.
- A tight rotation. With today’s tight canola rotations, there’s a high likelihood that Sclerotonia already resides in the soil or in neighbouring fields. Pulse crops and certain weeds (such as chickweed, stinkweed and thistles) are also host plants for the disease. If not properly managed over time, Sclerotinia can build up in the field, putting your canola crop at risk.
The optimum timing for a foliar fungicide application is when the canola crop is between 20 and 50 per cent bloom. This is a tight spraying window, so be prepared to spray on short notice.
- More from the Grainews website: New fungicides for 2014