By Madalyn Shires
In August 2024, the first reports of a corn stunt outbreak occurred in Oklahoma, Kansas, and Missouri. The disease has also been found in Arkansas and is suspected to be in Nebraska as well. In late September, a sample received from Deuel County was submitted to the SDSU Plant Diagnostic Clinic and was confirmed to test positive for corn stunt. This diagnosis is the furthest north corn stunt has ever been confirmed and reported in the United States.
Questions and Answers
What is corn stunt disease?
It is a spiroplasma disease (scientific name: Spiroplasma kunkelii) (a type of bacteria), which is spread by corn leafhoppers (Figure 1). This disease is limited to the phloem of corn plants and is only spread through leafhopper feeding. This spiroplasma is often not the only plant pathogen found in corn stunt symptomatic corn, but it is believed to be responsible for the majority of symptoms observed.
How do leafhoppers move the disease?
Corn leafhoppers feed on the phloem of plants using their stylet. The leafhopper acquires the spiroplasma from infected plants. The pathogen is then able to infect the leafhopper and later be transmitted to healthy plants through feeding. The corn leafhoppers feed on corn throughout the growing season. Management of leafhoppers is often impossible, as the leafhoppers will leave the sprayed areas and then return.
What are the symptoms of corn stunt?
Corn plants that are stunted in appearance, more bushy than expected, produce small or no ears, and have pink to purple colored leaves. Chlorotic stripes on leaves have also been observed in infected plants (Figure 2).
What to do if you suspect corn stunt in your field?
If you suspect that you may have been affected by corn stunt and you still have corn that has not dried down, you can take samples and send them to the SDSU Plant Diagnostic Clinic for testing. If plants have already dried down but you have pictures of suspected corn stunt plants, those photos can be emailed to the lab. For more information or further questions, reach out to Madalyn Shires.
Source : sdstate.edu