Common rustCaused by: Puccinia sorghi
Problem Category: Fungal Disease
Symptoms: Oval or elongated cinnamon brown pustules on upper and lower surfaces of leaves; pustules rupture and release powdery red spores; pustules turn dark brown-black as they mature and release dark brown powdery spores; if infection is severe, pustules may appear on tassels and ears and leaves may begin to yellow; in partially resistant corn hybrids, symptoms appear as chlorotic or necrotic flecks on the leaves which release little or no spore.
Comments: Disease is spread by wind-borne spores; some of the most popularly grown sweet corn varieties have little or no resistance to the disease.
Management: The most effective method of controlling the disease is to plant resistant hybrids; application of appropriate fungicides may provide some degree on control and reduce disease severity; fungicides are most effective when the amount of secondary inoculum is still low, generally when plants only have a few rust pustules per leaf.