DATE: 9/2/2005

CONTACT: Dr. John Mueller, (803) 284-3343, ext. 223

WRITER: Tom Lollis, (803) 284-3343, ext. 241

Soybean producers south of Santee need to protect against rust now

BLACKVILLE – Soybean producers south of Lake Marion and Lake Moultrie need to protect fields that have already flowered against Asian soybean rust immediately with a fungicide application.

“We found rust in leaf samples from a two-acre field here at Edisto Research and Education Center on Aug. 31,” said John Mueller, Clemson University Extension soybean pathologist.

He gave soybean growers advice on control measures for the potentially devastating soybean disease during the Fall Field Day program at Edisto REC Sept. 1.

“If you’re south of the lakes and your beans are somewhere between flowering and full pod, you need some sort of protection out there now,” he said.

Growers south of the lakes who have soybeans with small pods and high yield potential should strongly consider application in the next few days of a protectant strobilurin or a combination fungicide which also contains an eradicant triazole.

“This will prevent rust spores which land on your plants from germinating and will also offer some management of leaf, pod and stem diseases,” said Mueller.

Rust has not been found north of the lakes. For those growers the urgency to spray is not as great, especially with the current dry weather. For those growers, fungicide sprays can be delayed until pods are three-fourths of an inch long or they can piggy back fungicides with insecticide applications to save costs.

Producers who have applied a strobilurin in the last 7 to 10 days should not need to spray again until late next week.

“When growers have full sized seed and pods have started to change color, they are out of danger from yield losses due to rust,” said Mueller.

“Nearby fields which are not as mature will need to be protected, however,” he said. Anyone who plans to irrigate should wait until after irrigating to apply fungicides.

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