News

Southern rust: first case of the year confirmed

The first case of Southern Rust for this season in the US has been confirmed and another case is suspected, both further north than normal.

University of Missouri Plant Pathologist Kaitlyn Bissonette says the corn disease was found in Vernon County in West central Missouri on Tuesday.

“I was surprised that it showed up here first because we generally see it in the southern states like Texas, Louisiana and Arkansas before we ever find it here in Missouri.”

Bissonette tells Brownfield weather is likely the cause of its location. Southern states had an unusually cold winter and Missouri has had an abnormally warm and humid season, favorable for southern rust.

Preventative fungicides can be sprayed around the R3 stage, but with the slow progression of the disease, Bissonette encourages growers to only spray unexposed fields near confirmed cases.

“Applying a fungicide too early can also be an issue because the residual effect of the fungicide will wear off by the time a spore will land on the leaf surface. So, don’t apply a fungicide too early and obviously don’t apply one too late.”

She says Southern Rust is a fungal disease of corn that usually spreads North through wind currents and produces spores in the leaf tissue. It creates orange circular or oval lesions that break open the leaf surface, which can help tell it apart from similar diseases such as common rust.