On June 16 and June 22, 2026, the first corn leafhoppers of the year were detected in Missouri corn fields during routine field scouting in Boone County. These fields are part of the in-season monitoring led by Assistant Professor and State Extension Row Crop Entomologist, Ivair Valmorbida. Corn leafhoppers were collected directly from corn plants at the V5 growth stage. No corn leafhopper nymphs were found, suggesting these adults are migrants from the southern United States. Corn leafhoppers have also been detected in Oklahoma in early June. The first detection of 2026 in Missouri occurred approximately three weeks earlier than in 2025.
Research from South America, where corn leafhoppers are a greater concern, has shown that infection by corn stunt pathogens during vegetative growth stages, from emergence (VE) through tasseling (VT), can result in significant yield losses, as affected plants have a longer period to develop symptoms. It is not yet known whether the corn leafhoppers detected in Missouri carry corn stunt pathogens; therefore, growers should assume any corn leafhopper could be infectious. Corn stunt pathogens have been detected in Missouri in both the 2024 and 2025 growing seasons.
Although corn leafhoppers have been observed in Missouri this season, several of the fields scouted also had aster leafhoppers, Macrosteles quadrilineatus (Hemiptera: Cicadellidae), a species native to North America. Aster leafhoppers are common in Missouri corn fields, and they are not known to vector corn stunt pathogens. Adult corn leafhoppers are approximately 1/8 inch in length and vary in color from pale yellow to white. A key distinguishing feature is the presence of two dark spots between the eyes, each with a white halo around it (Figure A). The head of the corn leafhopper has no additional facial markings. In contrast, while the aster leafhopper also has two black dots between the eyes, these lack the white or light/yellow halo. Additionally, the aster leafhopper exhibits facial markings (lines or spots), darker wing veins, and a generally darker abdomen (see Figure B).
Corn leafhopper Two black dots between their eyes and no facial markings. (Photo: Ivair Valmorbida)
Aster leafhopper Tan body and presence of facial markings on the head. The aster leafhopper also has two black dots between the eyes. However, the light/white halos are not present. (Photo: Ivair Valmorbida)
Given the detection of corn leafhoppers in the state, growers should scout corn fields, particularly those at growth stages before R1. Visual scouting may be ineffective if insect numbers are low. For more accurate monitoring, consider using a battery-powered vacuum with a pantyhose stocking over the funnel or a sweep net to assess corn leafhopper presence in the field. Check field edges and the interior of the fields. When performing visual scouting during the vegetative growth stages, focus on whorl inspection where corn leafhoppers often remain concealed (Figure C).
Corn leafhoppers in the whorl of a corn plant. (Photo: Ivair Valmorbida)
Management of corn leafhoppers is complex and should involve multiple practices to reduce both the insect population and sources of disease inoculum. No economic threshold has been established for corn leafhopper in the United States; therefore, current recommendations suggest that foliar insecticide applications may be warranted when corn leafhoppers are detected in fields prior to the R1 growth stage. When selecting an insecticide, growers should consider those that are soft on natural biological control, as they can help suppress corn leafhopper populations. In addition, growers must follow insecticide label recommendations. More information on the biology and management of corn leafhoppers is available in the MU Extension publication G7109: https://extension.missouri.edu/publications/g7109.