Corn Leafhopper

Pest Overview

The Corn Leafhopper (CLH, Dalbulus maidis) is an invasive insect pest thought to have originated in Mexico and is distributed across the Americas. It was historically reported in the southern U.S., but in 2024 and 2025 it expanded its range and was detected in parts of the Midwest (Fig. 1). In Louisiana, CLH was detected in Franklin Parish in 2025.

The corn leafhopper is closely associated with corn, which is currently the only known reproductive host in LA. Both adults and nymphs feed with piercing-sucking mouthparts, primarily on the phloem, and can produce honeydew that supports development of black sooty mold, which can reduce photosynthesis. CLH can transmit a complex of pathogens (corn stunt disease), which contributes to its severe yield loss potential. Both maize bushy stunt phytoplasma (MBSB) and corn stunt spiroplasma (CSS) reproduce within plant phloem, compromising nutrient, hormone and sugar tranlocation. This triggers a series of physiological abnormalities on the plant. Symptoms include stunting, shortened internodes, leaf yellowing or reddening, multiple ears, excessive tillering, and poor kernel fill. Additionally, this insect can vector the maize rayado fino (MRFV) and Maize striate mosaic (MSMV) viruses, which cause the formation of yellow chlorotic spots that coalesce in strips along the veins and fine yellow vein-parallel stripes, respectively. Be mindful that genetics play a major role in plant response to these pathogens. Therefore, different hybrids may show variable symptoms at different severities. Also, multiple pathogens may occur in the same field at the same time.

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Corn Leafhopper Identification

1. Adults: 1/8 inch long torpedo-shaped body, and tan-colored. Look for two distinct dark spots between the eyes. In Louisiana, the most common species of leafhopper found on corn is the black-faced leafhopper which has darked-marked face and spots.

2. Nymphs: pale green and wing-less, often found on the leaf underside.

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Management Strategies

Scouting

How?

Use a sweep net or a battery-powered vacuum (with a fine mesh/pantyhose over the nozzle) to sample the whorl and underside of leaves. Be aware that populations build up on field edges going into the center.

When?

Scout early and continue throughout the vegetative stages and early reproductive stages. Extra effort in scouting particularly on late-planted corn and areas surrounded by drying down fields.

Threshold

Threshold is not yet standardized. If you suspect CLH in your field, please contact your extension agents.

Note: In LA, where corn is the only known host, early planting and volunteer corn control (such as removal by a killing frost) reduce infestation risk.

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Symptoms

Corn Stunt