As of Friday, five counties had confirmed southern rust: Otoe, Nemaha, Pawnee, and Richardson in extreme southeast Nebraska; and Clay in south-central Nebraska.
Clay County Extension Educator Jen Rees says the fungal disease has appeared eight of the last nine years in the state.
“It can’t survive the winter here in Nebraska and so it blows up on the winds from the south every year,” she says.
In 2006 and 2007 some producers faced a long harvest after the rust took hold.
“It can result in yield loss and it can also result in problems with stalk strength because when you have a lot of leaf area covered by the fungus, then it takes out those carbohydrate reserves,” says Rees.
Experts say farmers shouldn’t panic - southern rust can be treated. But before spraying they recommend scouting fields. Rees says first figure out how much is there, then factor in the corn’s growth stage and cost benefits of applying fungicide.
“Because our fungicides have about a three week residual, and so if we are spraying too early and southern rust gets in there at really high levels, then they may be looking at a second fungicide application, and with the current corn price, that doesn’t economically pay,” she explains.
Look-a-like diseases like common rust are out there too, so experts recommend getting help with making sure it is the southern fungus before taking action.
“Again, these are samples that we are getting out of numerous samples that have been coming in, and it’s usually just a small place in one field,” says Rees.
Southern rust favors wet and humid conditions, so specialists say irrigated fields are more at risk, as are late-maturing or replant fields.
Click HERE to visit the UNL CropWatch website and find out more.
Click HERE to go directly to the CropWatch southern rust update page (Aug. 1, 2014).