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Soybean rust arrives in Missouri

Soybean rust arrives in Missouri

Farmers should check fields


COLUMBIA, Mo. – Soybean rust has been identified in fields in Scott and Pemiscot counties. Farmers in southeast Missouri should check their soybean fields to determine their response to the potential danger, said a University of Missouri Extension plant pathology professor.


“Rust has been identified in two fields, and we’re actively surveying others,” said Allen Wrather, MU professor at the MU Delta Research Center in Portageville, Mo.


“Our suggestion is that farmers check their soybean fields for soybean growth stage and yield potential. If the beans in the top part of the plant are fully developed, no action is needed. However, if the beans are still developing and yield is expected to be 40 bushels per acre or greater, the field should be sprayed with a fungicide for rust management.”


Soybean rust developed a few weeks earlier this year than the past year’s mid-October date, he said.


“Weather has a huge impact on the development of rust,” Wrather said. “Rust developed in eastern Texas, eastern Oklahoma and south central Louisiana. It started to spread as the weather pattern changed. Temperatures became more favorable, and rains became more frequent. Then, rust began to spread farther north.”


Wrather said if the spread of soybean rust had occurred four weeks earlier, many of the fields would be at risk, but farmers have fewer reasons to worry this late in the growing season.


“Most soybeans in the southern parts of Missouri have already reached the point where soybean rust is not a threat,” he said.


Farmers looking for information on fungicides should check the MU Delta Center’s guide online at