MISSISSIPPI STATE -- Asian soybean rust has not been found in Mississippi as of June 28, a fact confirmed by the team canvassing the state’s soybean crops, sentinel plots and Kudzu each week.

A group of Mississippi State University Extension Service plant pathologists, members of the Soybean Management by Application Research and Technology program, and other Extension personnel, researchers and trained consultants search daily for the disease. Billy Moore, an Extension plant pathologist emeritus, said there is no reason for concern at this point.

“We have found no rust in Mississippi, and we will keep producers constantly informed,” Moore said. “The entire state is being monitored for the occurrence of soybean rust. There have been false rumors of the occurrence of rust, but any rumor should be checked out for reliability.”

A soybean field in Louisiana 20 miles west of Wilkinson County has tested positive for the fungus. Kudzu patches south of Wilkinson County in New Iberia, La., and Kudzu patches in two Louisiana parishes south of Amite County also have tested positive. Because these Louisiana parishes where rust has been found are close to some Mississippi soybeans, team members recommend fungicide applications for producers in Amite, Franklin, Adams and Wilkinson counties.

“As a result of these findings, we are suggesting fungicide applications containing both strobilurion and triazole active ingredients to soybeans at R3 and R4 growth stages, to prevent a lose from rust,” Moore said.

Asian soybean rust spores can spread rapidly by wind and grow in moist conditions. When the fungal spores enter a field, conditions have to be optimum for germination and infection, Moore said. It can take up to six hours under ideal conditions for an infection to occur and nine to 10 days more for symptoms to be expressed and new spores to be produced. After a successful infection from a spore, it may take three to four weeks for enough soybean leaves to become infected to be detected in the field.

“This is why application of fungicides has been suggested for the four-county area. It is more likely that viable spores would be present in that area as a result of spore production in infected soybeans and Kudzu sites in Louisiana,” Moore said.

For much of the rest of the state, weather conditions have not been ideal to support the spread of soybean rust.

“For the most part, areas north of I-20 have been hot, dry and very unfavorable for rust development. The fungus is subject to destruction by solar radiation, and the intense sunlight would not provide the opportunity for it to move very far and still remain viable,” Moore said.

He added that any producer who recognizes a problem in the field should call the local Extension office.

For immediate soybean rust updates, call the toll-free soybean rust hotline at 1-866-641-1847.

Writer: Courtney Coufal
Contact: Billy Moore, (662) 325-4591