A Pre-Seed and In-Crop Control Plan for Volunteer Canola

Yes, that’s a swath in a tree

Canola volunteers can be tricky to control in the most “average” of years. But we all remember last year when 100km/h winds came and blew around canola, leaving bushels laying in fields, ready to germinate this spring. But just how much canola is in one of your fields?

Here is some math to get an idea:

Assuming a 5-gram thousand kernel weight (TKW):

(454 grams in 1 lb) = 454/5gram TKW = 90.8 x 1000seeds = 90,800 seeds in 1 lb of canola seed.

Roughly 50 lb of canola in a bushel = 50 x 90,800 = 4,540,000 seeds

So if you lost roughly one bushel an acre you could have about 4.5 million seeds an acre on the surface.  If you lost 5 bu/ac that number jumps to 22.7 million seeds an acre or 521 seeds per square foot. Yeah, it’s not pretty.

Now, I recognize that even if you lost 5 bu/ac to shattering or blown swaths, not all of those seeds are going to germinate and still fewer will result in actual plants, as many will have been eaten by birds or killed via weathering. But just four volunteer plants per square foot could result in a roughly 25% reduction in yield in this year’s wheat crop, for example.

The bottom line then is if you’re anticipating volunteer canola trouble (even in the absence of excessive shattering last year), how do you deal with them?

First and foremost, ensure you are doing everything you can to produce a vigourous stand, starting with good seed, a heavy seeding rate based on TKW and a targeted population with a registered seed treatment, put down at a consistent depth with a starter blend of fertilizer. This gets your crop started off on the right foot and in good shape to compete against a swarm of volunteer canola.

Next, but just as important, be sure you are going in with a timely pre-burn glyphosate application with some sort of residual based additive such as PrePass from Dow AgroSciences, Express SG and Express PRO from DuPont (assuming this is prior to a cereal crop). If you’re planning to seed a pulse crop on your canola acres there are products like Heat from BASF which can provide some residual suppression.

Finally, be prepared to go in early with your in-crop broadleaf application. This means you may be going in at the 2-leaf stage on your cereal crops, maybe earlier. Take a look in your guide and see if some of the earlier registered products are an option for you, such as Barricade from Dupont, Frontline XL from Dow AgroSciences, or Infinity from Bayer CropScience. There are many other registered options out there, but see which one fits for you. Lastly, you may have to go in with a second broadleaf application, so be prepared for this.

Getting a good handle on these volunteers this spring is going to be important, but it’s important every year. Developing a short-term plan for this year should be part of a longer-term plan in general.

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