Scouting fields is a big responsibility. One of the biggest pitfalls is to jump to conclusions once you see something wrong, without considering all the possibilities.
It goes both ways – you want the damage to be either the seed company's or the chemical company's fault. Your perception, at least, is that they want it to be your fault, or at least some factor beyond their control. Sometimes the truth is in the middle. Other times things just aren't what they seem.
Mark Lawson is a farmer near Danville, and a technical rep for Syngenta. He shares this story from scouting this season already. He was called to a soybean field where it appeared that a virulent case of Rhizoctonia root rot was killing soybeans. The characteristic red lesions were visible at the soil line. That's typically a key indicator for rhizoctonia disease.
More than one brand of soybeans was planted in the field, and all were affected. That's key information you need to supply to someone scouting for you. One variety was a Northrup King brand, a Syngenta company, and the seed was treated with Cruiser Maxx and Vibrance. Lawson says Vibrance gives excellent control of rhizoctonia, making this situation more difficult to explain.
After asking more questions, Lawson and other scouts arrived at a more plausible explanation. The field received a very heavy rain just after a cell membrane disruptor herbicide, a PPO inhibitor, had been applied. After checking on what type of injury this herbicide could produce, the agronomists discovered that under certain conditions this class of chemicals can produce the exact symptoms which mimic rhizoctonia root rot. Replanting was necessary in this case. But knowing the cause was crucial. If it had been rhizoctonia, replanting might have been futile because the second planting might have been affected as well.