Wheat School: Should you spray with a wet wheat canopy?


Many producers across the Prairies are spraying — whether they are starting, finishing, or somewhere in the middle.

With unpredictable weather, many are asking the question: We want to spray, but the canopy is wet. Should we go?

According to Tom Wolf, of AgriMetrix Research and Training, the answer isn’t as simple as one may think.

“The concern is obviously that the spray hits the wet canopy, and maybe it will roll off because the canopy is that wet that it induces runoff. That can happen because our sprays typically contain surfactants, and those surfactants can then lower the surface tension of the dew, and that causes runoff, so we may lose some product,” explains Wolf.

He says that when it comes to spraying into a wet canopy, you also want to double check the consistency of what you are spraying.

“The spray might be so coarse that the big droplets create that momentum, and will also create that runoff. So we’re due to lose some proportion of that spray.”

Wolf notes that when taken to the lab under some conditions, it was found that you lose around 30 per cent of your dosage when you spray into a very wet canopy, however, there was no real loss of efficacy. So your losses may not be as high as originally anticipated.

“The story really is that it’s possible that the wetness of the canopy also helps uptake in some way because it hydrates the cuticle. So maybe they are counteracting effects.”

To learn more, check out the conversation below with Kara Oosterhuis and Tom Wolf, filmed at canolaPALOOZA, in Lacombe, Alta:

Click here for more Wheat School episodes.

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