CROP ADVISOR’S SOLUTION SOLVED – HERBICIDE DAMAGE
Bob had some potential herbicide damage on his trait canola. The plant population was thin with varied maturity. Three days post-application, a distinct block pattern of damaged canola spanned the last two fields that the producer sprayed, consistent with one full 80-acre tank.
Some of the older plants had yel lowing on the upper leaf area and stem, while some of the younger plants displayed a white tinge to the upper portion where the spray would have fully hit. Bob used bulk herbicide totes and was concerned the last tank had higher levels of surfactant or carriers that could cause extreme burn.
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After sending in a number of photos, a representati ve came out to view the site seven days after application. To begin eliminating possibilities, we started at square one with the product itself. A number of tissue samples and samples from the bottom of the tote were sent to the manufacturer’s quality assurance lab for analysis and to identify any anomalies. They were asked to send a report indicating any potential contamination, unusual formulation, and other product quality concerns such as crystallization, concentration, and viscosity.
Our next step was to acknowledge the extreme plant damage. By day seven further whitening was noted on the top leaves. However by day 14, it seemed that the plants were trying to actively grow through the stress. The larger plants pushed out early pods and grew into a witch’s broom formation of underdeveloped, spindly pods. A number of plants were picked for tissue samples and sent away to a university lab for visual analysis, and to a local analysis lab for a full herbicide trace.
Over summer, we continued to monitor the crop as it showed reasonable recovery of the damaged plants, though maturity was lengthened due to the stress of the mystery tank.
Next, we gathered the results from the three separate labs. Those labs told us the herbicide sample contained a liquid suspension consistent with the product trait. No settling, concentration or separation issues were found. One agronomist, however, visually noted that the symptoms indicated more than one herbicide present in application, and tissue sample results indicated the presence of both glyphosate and glufosinate ammonium in the damaged plants.
With these results, I drove out to see Bob. Both bulk glufosinate ammonium and bulk glyphosate were loaded on the trailer with hosing for both units present, but unhooked. It seemed clear what had caused the problem in Bob’s canola.
The growing season is a stressful and hectic time for producers. It’s important to remain in the habit of slowing things down. In a split second, anyone can flip the wrong switch and load the wrong product. Even at a small concentration, such a mistake can lead to a damaged crop and a long season of stress. Ensure your products are mixed properly, and convince yourself to double-check you’ve got the correct products going on the right crops.
Tracy Friesen is a Richardson International sales agronomist in Spirit River, Alta.
CROP ADVISOR’S CASEBOOK WHAT’S WRONG WITH JOHN’S CANOLA?
I first spoke with John in February when he called to find out about the yield data and variety of glufosinate ammonium-resistant canola. He was excited about the new air drill he’d purchased for spring, so we talked about his fertilizer program, too. We decided he should take advantage of the NH3 kit on his air seeder and so we came up with a blend of 90 pounds of NH3 and 30-25-20 blends at 118 pounds per acre.
I didn’t hear from John again until the end of May, when he called to say he had one of the best-looking canola crops in the country. I figured I better see if for myself and headed out to the Waskatenau area, where he has 2,000 acres of wheat, barley and canola.
Indeed, John did have a fantastic-looking start and we discussed the proper time to spray. We headed into the crop and found it to be in the two-to three-leaf stage with plant counts averaging nine plants per square foot. We agreed the time was right. John decided he’d start the next day and finish in time to go fishing over the weekend.
The next time I heard from John, a week later, he was in a different mood.
“I don’t know what’s happened,” he said with worry. “I’d say 60 per cent of the field is turning yellow. I must have mixed the glufosinate ammonium wrong, or maybe I used too much. Can you come out and take a look?”
Sure enough, John’s canola was not the beauty it had been the last time I’d seen it. Walking out into the field, we found mottling leaves and plants that were dying off.
We worked through the potential problems, starting with his application process. Everything checked out. The sprayer was set properly, he used the correct water volume, his water source was fine, the application ratio followed manufacturer’s suggestion… everything checked out.
John’s wife kept daily weather records, but nothing seemed abnormal there. We’d seen some rain but no frost and plenty of sun.
So why were the plants dying now?
Send your diagnosis to COUNTRY GUIDE, 1666 Dublin Ave., Winnipeg, Man., R3H 0H1; e-mail [email protected];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 solved the mystery, will appear in the next Crop Advisor’s Solution File.
