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Crop Advisor’s Casebook – for Oct. 17, 2011

Bob, one of my agronomy clients, is a serious grain producer who farms 5,500 acres of spring wheat and canola south of Yorkton, Sask. Bob and I try to scout his fields together every seven to 10 days to monitor crop progress. Until the beginning of July, Bob s wheat crop had been progressing well, but when I called him on July 8 to schedule our weekly scout, he said he was concerned about one of his fields. Some areas are turning brown and completely dying, mostly on the hilltops. I think it s damage from a chemical, he said.

Bob said that established spring wheat plants in the four-to five-leaf stage were dying off in randomly-occurring patches on ground situated at higher elevations. He said he had noticed the symptoms seven days after spraying, and this was why he thought it was an herbicide issue.

When I arrived at Bob s farm, we thoroughly scouted the field. I noticed patches of wheat that had grown to the three-to four-leaf stage before it had rapidly withered and died. No other plants were growing in the patches, and the wheat had dried up completely. The number of dead plants indicated the germination rate had been excellent, with a plant stand population of 40 or more plants per square foot.

According to Bob s records, his seeding rate and depth were correct, as was the fertilizer rate. His herbicide application rates and procedures were also correct. Looking back on this field s herbicide application history, nothing jumped out at me that could be the cause of the issue we were addressing. To me, the problem did not seem to be a seeding or herbicide application error.

Next, we spent a lot of time looking for insects, such as cutworms and wireworms, in the affected areas. However, not one worm of any kind was found above ground or slightly below ground in any of the patches we examined.

None of Bob s other fields were exhibiting these symptoms, so I thought there must be something different about the seed planted in this field, or the field itself.

Can you think of anything, anything at all, that was done to this field that was different from all the rest? I asked.

Not really, said Bob. But I this is the only field where we didn t apply a seed treatment.

Ah-ha, I thought. I began to explore this new avenue by pulling up some plants from the affected areas. Upon examination of the root mass, I knew what was causing the dead patches of wheat, but I sent a few plants to the lab for analysis to be sure.

The bad news is that we can t do anything to reverse or fix the problem in this field this year, but the good news is that I ve solved your problem and we can prevent it from happening next year, I told Bob.

Why are patches of dead wheat appearing in one of Bob s fields? Send your diagnosis toGrainews, Box 9800, Winnipeg, MB, R3C 3K7; email [email protected] or fax 204-944-5416 c/o Crop Advisor s Casebook. Best suggestions will be pooled and one winner will be drawn for a chance to win aGrainewscap and a one-year subscription to the magazine. The best answer, along with the reasoning which solved the mystery, will appear in the next Crop Advisor s Solution File.

ChadZavislakisasalesagronomistat RichardsonPioneerLtd.atYorkton,Sask.

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CROP PRODUCTION

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