Based on firsthand observations Ohio State University plant pathologists say that with diligent scouting, timing of fungicide applications and a blessing from Mother Nature, soybean rust is easily manageable.
Anne Dorrance, an Ohio State research plant pathologist with the Ohio Agricultural Research and Development Center, was part of a nationwide envoy of soybean pathologists and agronomists who traveled to Brazil to observe the impact of soybean rust on the country's crop. The purpose of the trip was to get a better handle on what U.S. soybean growers might expect from the disease as it is anticipated to spread northward.
"The recurring theme throughout the trip was that the fungicides work," Dorrance says. "We saw humongous fields in Brazil, and the only place where we could find active rust lesions were in the check plots and in the skips of the sprayers. U.S. producers will actually have more resources available than the Brazilians to assist in tracking and monitoring soybean rust, and to assist in the best timing of fungicide applications."
Soybean rust, an aggressive disease that attacks the crop from the bottom up, was identified in eight states late last year. Dorrance says that the lessons learned in Brazil will help U.S. growers become more knowledgeable regarding the behavior of the disease, preventive maintenance and effective control in the event soybean rust were to continue spreading northward into such states as Kentucky, Ohio and Indiana.
Some take-home tips that were revealed during the trip to Brazil include:
Each of the three types of fungicides that are available -- strobilurin, triazole and chloronitrile -- has a shelf life. The longer the window between application and the disease, the less effective the fungicide will be.
"If you’ve ever walked through a soybean field in the morning, you come out with your pants soaking wet. The dew lasts longer, humidity lasts longer, it's nice and cool. It's a very favorable environment for the fungi and it's where we need to be looking and where we need to be hitting the applications. And I'm not talking about good coverage or excellent coverage, but outstanding coverage."
Luckily, Ohio growers may not have to concerns themselves with correctly diagnosing the disease. Thirty sentinel plots have been set up throughout Ohio to help diagnose soybean rust. In the sentinel plots, nearly every leaf will be monitored throughout the season either on a weekly or bi-weekly basis. The first diagnosis of soybean rust in Ohio would most likely come from these sentinel plots.
The sentinel plots are sponsored by check-off support through the United Soybean Board North Central Soybean Research Program and the Ohio Soybean Council, and coordinated by Ohio State and the Ohio Department of Agriculture.