David Miller, Director of Research and Commodity Services, Iowa Farm Bureau Federation

I farm approximately 550 acres (corn-soybean rotation) in the central part of southern Iowa. As far as I know, I do not have a problem with herbicide-resistant weeds on my farm. Some of the management practices that I use to minimize the risk of weeds developing herbicide resistance on my farm include regular crop rotation, use of multiple herbicide technologies, and avoidance of “half-rate” applications.2

But the question to be addressed is, “What are the impediments to using best management practices?” I believe the primary impediment is the near-term costs associated with implementation of best management practices to forestall a problem that may or may not develop at some unspecified time in the future. The corn seed I buy often has multiple stacked traits. Imbedded in the cost of that seed are technology fees for these traits. I pay those fees even if I choose to use a different herbicide and not use the herbicide-resistant trait incorporated into the seed. I do this because I want (or need) the other traits contained in the stack, but the choice to not use the herbicide-resistant trait can result in a $15 to $20 per acre increase in my herbicide costs in those years when I use alternative herbicide technologies.

The second most important deterrent to implementing best management practices with respect to minimizing herbicide resistance in weeds is strict adherence to no-till production practices. Eliminating tillage from the production protocol increases reliance on post-emergence herbicides and, realistically, on glyphosate-based formulations.

There are other impediments to using best management practices for managing herbicide resistance in weeds. They include weather-induced delays that can result in untimely herbicide applications, monoculture crop rotations due to dominant economics for that particular crop, and the “ease” of using a single herbicide technology across multiple crops, rotations, and geographies.

Steve Reeves, Vice President, Bank of Fayette County

Lending institutions have to be careful as to how they guide producers because of lender liability laws. I encourage best farm practices such as rotation, mowing end rows before weed seeds mature, and applying recommended herbicide application rates. As I perform preseason cash flows, all formulas are based on the recommendations. Any variance could result in changes in the net income to the producer. I do see the possibility of herbicide-resistant weeds adding to the variable cost (e.g., labor, fuel, and herbicide) in the future as farm margins are narrowing.

Dale Shaner, U.S. Department of Agriculture, Agricultural Research Service

The major impediment to using best management practices from an industry point of view is the difficulty in coordinating recommendations except in general terms. The


2Half-rate application refers to using less than the amount of herbicide recommended on the label instructions.

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