Pulse School: Navigating ideal timing for spraying

(Kara Oosterhuis/RealAgriculture)

Timing crop protecting sprays is an important decision to make to ensure the health and quality of the crop. While sometimes weather conditions don’t allow farmers to be as precise in timing as they’d like to be, there are some variables that should be taken into consideration when weighing the options of getting back out in the field, post-seeding.

For this episode of the Pulse School, we are joined by Mike Palmier, owner of MaxAg Consulting, in west central Saskatchewan. He takes us through what is the critical weed-free period for different pulse crops, what to do if the weeds have grown bigger and faster than anticipated, and if it’s advisable to save a trip across the field and mix herbicides and fungicides together in the same pass.

When we are looking at peas, Palmier says it’s important for that crop to stay as weed free as possible straight from emergence all the way up to the five or six node stage, making burn off extremely important.

“I would really suggest to wait until there’s some weeds up to get a proper burn off, on that we have limited options in crop if we do have weeds escape,” explains Palmier. “Also, plan ahead on your pulses and get a herbicide residual product on there either in the fall or the spring, in order to get some residual action on the planned weeds or the expected weeds on that field to maintain that critical weed free period.”

For lentils, he says the critical weed-free stage is between five and 10-node stage, again making burn off important as farmers are restricted to group two herbicides which for crop safety reasons, should be done early in the crop.

Now, if for any reason, producers miss that ideal window of spraying and they wake up to see the weeds have maybe gotten away on them, Palmier says the options are limited but increasing water volume can certainly help with droplet size and getting the herbicide where you want it. Otherwise he says to do your best to spray in ideal weather conditions and do everything at that point to maximize the efficiency of the product.

Some may be tempted to save a pass in the field and mix herbicides with fungicides, in order for this to be effective, Palmier says there are some other factors to consider and it’s not a cut and dry, yes or no answer.

“Really, it depends on the lifecycle and the stage of that plant, your environmental conditions, the size of the plant, how uniform the canopy is within that. Generally speaking, fungicide at herbicide timing, if it’s a proper staging, which would be six node and earlier on peas and nine node and  earlier on lentils, doesn’t necessarily really show a lot of return on investment,” says Palmier.

This is because, at that stage of the plant, disease conditions aren’t quite as prevalent and pathogens are just starting to develop.

On the flip-side, if the idea of combing the herbicide and fungicide is to apply it later in the growing season, closer to the flowering stage, Palmier says it may be worth considering putting a fungicide in with your herbicide at that time.

“If we have to get out there, then you might need to look at it especially if you have a large seed lentil canopy where you’re concerned about closure. If it’s wet within that canopy, and you’re spraying at a ten, eleven, twelve node lentils, it might make sense,” says Palmier.

For this and all of our Pulse School episodes, click here.

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