Control Your Variables To Manage Soybean Rust

Make your cropping decisions and prepare for spraying with an Internet decision support tool. Compiled by staff

Published on: Feb 21, 2005

The arrival of soybean rust in the United States will present farmers with a number of uncertainties about exactly how to respond to the problem for the upcoming growing season, according to a recent study by Peter Goldsmith and Gary Schnitkey, assistant professors in the Department of Agricultural and Consumer Economics at the University of Illinois.

The situation for farm managers in the United States is much different than for producers in South America, says Goldsmith, who also serves as the Fellow in Agricultural Strategy at the National Soybean Research Laboratory. "Because the spores are present all year round in that region, growers can make the simple decision to apply multiple spray treatments each year. In the higher latitudes, where killing frost is present, the extent of the rust problem will differ considerably from year to year."

He notes that this key difference leaves U.S. growers with important decisions about what do about the threat for the upcoming growing season. "Farmers will have to respond in some way to this new threat," says Goldsmith. "The decisions can range from doing nothing at all to applying multiple spray treatments. Growers can even decide to avoid planting soybeans completely. Organic soybean growers face a special challenge because there is no known organic treatment for rust."

An area of concentration should be on cropping decisions and preparation of spraying equipment and materials. To make this process easier, Goldsmith and Schnitkey developed a decision support tool that is available on the Internet at www.farmdoc.uiuc.edu/.

"The results show that the corn-soybean ratio will have less impact than the activities involved with scouting and good spray management," Goldsmith says. "Because timing of the spray is critical, growers should make sure the proper equipment and fungicides will be available if needed. One way to begin this process is to develop good communications with fungicide sales representatives and spray contractors."

According to Goldsmith, managers will need to focus on a few key variables in making the decision about how to respond to the rust situation. "One variable creating uncertainty is the lack of experience in dealing with this disease," he says. "Most soybean growers are unfamiliar with using fungicides. Spraying for rust will add many new demands on the state's spraying infrastructure, protocols, and skills. More narrowly, growers have no previous experience with this disease to guide them in making decisions."

Goldsmith points out that there are also many uncertainties about the extent and range of the disease and how it will impact markets. "We still do not know if the disease will even be present in 2005. If it is present, it is still uncertain when rust might arrive during the growing season or how it might be distributed across a particular region or farm," he says. "We also do not have any idea what its final impact will be on crop yields and prices."

He suggests in the study that one way of dealing with all the uncertainties is to focus management on a few key activities that are both controllable and have positive impacts. At the top of the list are management activities that focus on scouting, disease management, and spray-related decision making.

"There is plenty of time before the infection might make its appearance," Goldsmith says. "There is a large amount of high-quality educational materials available. This creates an opportunity for generating returns to good management. Those who are prepared will outperform those who are not."

He points out that there are some variables that are completely uncontrollable, such as grain prices and the rate and location of the rust infection.

"These variables need to be factored in and analyzed, but they cannot be directly managed," he says. "The key is for growers to place the major focus on the high impact, controllable variables. That means learning about the disease and about how to scout and treat it."

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