Tracy Friesen is a Richardson International sales agronomist in Spirit River, Alta.
Early last July I received a call from Bob, a 3,000-acre grain producer in my area regarding potential herbicide damage on his trait canola. It had been a very hot and dry spring and the plant population was thin, with plant maturity ranging from four-leaf to 10 per cent flower.
Three days after application, a distinct block pattern of damaged canola spanned the last two fields that Bob had sprayed, consistent with one full 80-acre tank.
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Some of the older plants had yellowing on the upper leaf area and stem, while some of the younger plants displayed a white tinge to the upper portion of the plants where the spray would have fully hit.
Because the pattern followed the sprayer line, we ruled out fertility, seed quality and seed placement concerns as the cause.
Bob told me the two damaged fields were the last 1,500 acres of the same canola variety to be sprayed and that he had used bulk herbicide totes through his chemical handling system. He remembered being concerned the last tank appeared to have higher levels of surfactant or carriers, and he wondered if this had resulted in extreme surfactant burn.
“Did it settle out to the bottom, become concentrated and cause this damage?” Bob wondered. “Of all the other spraying I’ve done, I haven’t had any damage concerns. Why now?”
There had been no other crops sprayed in between fields of the same variety. Previously he’d sprayed a different line of tolerant canola with its companion herbicide. Having seen symptoms similar to this before when another local producer’s custom sprayer accidentally sprayed a glufosinate ammonium tolerant canola field with the wrong in-crop companion spray, my first hunch was that somehow glyphosate has made its way into this tank, with enough to damage the plants and disrupt growth but not enough to kill them outright. Common sense would suggest any potential glyphosate residue in Bob’s tank would show on the first acres sprayed, and no visual symptoms were noted on any other acres.
What was the issue in Bob’s field and what could he do to avoid the problem in the future? Send your diagnosis to COUNTRY GUIDE, 1666 Dublin Ave., Winnipeg, Man., R3H 0H1; e-mail ksimonson@directfocus.com;or fax 204-947-9136 c/o Krista Simonson. Correct answers will be pooled and one winner will be drawn for a chance to win a COUNTRY GUIDE cap and a one-year subscription to the magazine. The correct answer, along with the reasoning which solves the mystery, will appear in the next Crop Advisor’s Solution File.
