Corn Growers Urged to Scout for Southern Rust

Corn growers are being encouraged to monitor their fields as southern rust continues moving north.

Iowa State University Extension says the disease has been confirmed in four Iowa counties. Current incidence and severity remain low, but warm and humid conditions can allow southern rust to spread quickly.

Unlike tar spot, southern rust does not survive northern winters. Its spores are carried north by winds from southern states each growing season.

Agronomists say growers should consider crop maturity, hybrid susceptibility, weather conditions and confirmed disease levels before deciding whether to apply a fungicide. Tar spot also remains a concern because the disease can survive in infected crop residue.

Southern rust arrived later this summer than it did last year, and disease pressure has remained lower so far. Iowa State University Extension