Southern Rust Found In 24 Iowa Counties

Southern rust is found every year in Iowa being caused by the fungus Puccinia Polysora (puk-sin-ee-ah). As of August 11th, according to the Crop Protection Network Southern Rust Corn Map, 24 counties have now reported the disease being present. The 4 closest to the listening area are Cerro Gordo, Butler, Mitchell, and Blackhawk counties.

Virgil Schmitt, Iowa State University Extension and Outreach field agronomist located in southeastern Iowa, gave his advice in his recent newsletter. Here are the key points you should know: Some hybrids are resistant, and some are susceptible. Keep scouting. Fungicide applications to susceptible corn are most beneficial between VT (tasseling) and R3 (milk stage). Southern rust favors temperatures of 77 to 88 degrees F, more than eight hours of leaf wetness and greater than 90% relative humidity which has been common in the state this year.