Seed-treatment choices

A corn grower doesn’t have many seed-treatment choices, Knake says. “Your seed company has decided what will be on its seed—it’s a blanket treatment. You might have a choice on a higher insecticide rate than the base treatment, and you could order a nematode control, but that’s about it.”

Soybean treatments have many more choices, for insecticides, fungicides and Rhizobia inoculants, Knake says.

He believes the whole package is best because it reduces risk. “Planting earlier, planting quickly, using crop residues—all favor seed treatment.”

Tristan Mueller agrees with him. He’s a program manager who helps coordinate on-farm evaluations for the Iowa Soybean Association’s On-Farm Network who previously worked with seed treatments. “Generally our on-farm trials haven’t shown large differences between seed treatments on corn or soybeans, but there’s a reason both are treated,” he says. Reduced corn stands do not compensate like soybeans—you’ll lose yield, he adds. “The trend is toward soybean treatment. I’d recommend treating most of your soybeans with a fungicide and an insecticide to reduce the risk of replanting. And I believe there’s a good chance of the treatment paying for itself in higher yields because of better stands and plant vigor.”

Ohio State University Plant Pathologist Anne Dorrance, and entomologists Ron Hammond and Andy Michel, have found success with seed treatments in soybeans during the all too common wet years. But if they could predict a dry year like 2012 they would say, “don’t treat your seed at all.”

In their research against water molds using metalaxyl and mefenoxam, they recommend the high rates to save stands and stop replanting, which deliver yield gains come harvest. They found this to be true in poorly drained fields, in no-till, in continuous soybeans and in a corn-soybean rotation.

When looking at the Strobilurins, the researchers find some helpful activity on some Pythium diseases, and good help with seedborne Phomopsis. fludioxinil (Maxim) has shown excellent activity on Fusarium, Rhizoctonia, Sclerotinia and Phomopsis. Sedexane, a new mode of action, has good activity on Rhizoctonia. Ipconazole has good activity on Fusarium and Rhizoctonia. Penflufen is also good on Rhizoctonia.

See more details of their recommendations, including insecticide seed treatments.