Itching to Swath? A Handy Online Tool for Determining Pre-Harvest Intervals on Canola

It’s mid-August and if you’re not already swathing or combining winter wheat, you’re checking canola fields daily for insect feeding or seed colour change. First off, high fives all around, because that’s what you should be doing now — insects like lygus bug and bertha armyworm can be causing serious damage this time of year. Also, swathing at the ideal time maximizes yield and quality, so you get a gold star for being vigilant.

Of course, what happens when late disease pressure or excessive insect feeding and swath timing collide? Well, then farmers need to be aware, and truly abide, the pre-harvest interval (PHI) between spraying and cutting.

Thankfully, the Canola Council of Canada has an easy to use website — — that is clear, concise and visual for determining PHI. Already sprayed fungicide or insecticide and need to check the PHI? Use the first option. Have a timeline in mind and want to check your options? Use the second slider to see what works in the timeline you think you have. Have a spray scheduled? Sync your calendar so you know when it’s time to go.

And, always remember that the pre-harvest interval is from the time of application to the time you cut the crop, not from spraying to harvest.

Happy swathing, y’all!


RealAgriculture Agronomy Team

A team effort of RealAgriculture videographers and editorial staff to make sure that you have the latest in agronomy information for your farm.


Why invest in growing hemp?

Hemp is often seen as a new crop, and in retrospect, it still is. Only allowed to be grown in Canada since 1998, there haven't been the decades of research and experience with hemp as with other crops. Jan Slaski, senior researcher with Alberta Innovates - Technology Futures, based in Vegreville Alberta, says that southern…Read more »


Leave a Reply