Southern rust is a leaf disease of corn that is caused by the fungal pathogen, Puccinia polysora. The disease is recognized as clusters of small, circular (1/16” diameter) spots that produce thousands of bright orange urediniospores on the upper side of the leaf (Fig. 1). With southern rust, there are multiple disease cycles during the growing season.

In 2025, the effect of commercial fungicides on foliar diseases of corn were evaluated at six ISU Research and Demonstration Farms: Northwest Research Farm (NWRF), Northern Research Farm (NRF), Northeast Research Farm (NERF), Armstrong Memorial Research Farm (lost due to wind damage before tasseling), Ag Engineering and Agronomy Farm (AEA), and Southeast Research Farm (SERF). Fungicide products evaluated and timing of application are shown in Table 1.

The Iowa State University Pesticide Safety Education Program has revised several applicator manuals and exams to reflect the updated pesticide applicator certification and training rules implemented by the Iowa Department of Agriculture and Land Stewardship on Jan. 1.

Spray drones are increasingly being evaluated by Iowa farmers as an additional tool for crop input application. When used appropriately, these systems can provide flexibility for timely applications, reduce field traffic, and improve access to areas that are difficult to reach with traditional ground equipment.

To maintain your private pesticide applicator certification, you must either pass an exam every three years or attend an approved Private Continuing Instruction Course (P-CIC) between December 1 and April 15 each year your certification card covers.