What Is Pasture Mealybug, and Where Is It Located?

The pasture mealybug is a serious pest of forage grasses that causes “pasture dieback,” leaving expanding patches of yellowing, weakened and ultimately dead turf.

This invasive species, never before reported in North America, has been confirmed in multiple southern Texas counties since mid-April and is already causing significant damage to pasture acreage across the Lone Star State.

These fields show grass patches becoming brown or necrotic, or patches that are completely dead. There have been extreme cases where entire fields show symptoms of grass desiccation.

According to Texas A&M Agrilife Extension, pasture mealybug (Heliococcus summervillei) is an introduced pest and a newly recorded species in the U.S.

Texas Agriculture Commissioner Sid Miller issued an urgent alert Dec. 10 to producers across the state to inspect their pastures.

The release says the Texas Department of Agriculture (TDA) is working closely with Texas A&M AgriLife Extension and USDA’s Animal and Plant Health Inspection Service (APHIS) to coordinate a rapid response and protect Texas producers.

First described in Australia in 1928, it has devastated millions of acres of grazing land there and has since spread globally, causing severe financial impacts. Its rapid reproduction, hidden soil-level feeding and broad host range make it a significant threat to pasture health and livestock operations.

(Photo: Stephen Biles)

“This is a completely new pest to our continent, and Texas is once again on the front lines,” Miller says. “If the pasture mealybug spreads across Texas grazing lands like it has in eastern Australia, it could cost Texas agriculture dearly in lost productivity and reduced livestock capacity. TDA is working hand in hand with federal and university partners to respond swiftly and protect our producers from this unprecedented threat.”

The estimated impact area currently includes 20 counties, including: Cameron, Hidalgo, Willacy, Refugio, Calhoun, Victoria, Goliad, Dewitt, Lavaca, Fayette, Jackson, Matagorda, Brazoria, Galveston, Wharton, Colorado, Austin, Washington, Burleson, Brazos and Robertson. AgriLife entomologists have submitted a formal Pest Incident Worksheet documenting significant damage to pastures and hayfields in Victoria County.

Research trials are underway to determine the best integrated pest management options. Currently, there is no known effective labeled insecticide for pasture mealybug.

Affected plants include: Bermudagrass, Bahia grass, Johnsongrass, hay grazer (sorghum–sudangrass), St. Augustine grass, various bluestem species, and other tropical or subtropical grasses. Damage can occur in leaves, stems, and roots.

Symptoms:

• Yellowing and discoloration of leaves within a week of infestation.
• Purpling or reddening of foliage.
• Stunted growth and drought stress despite rainfall.
• Poorly developed root systems.
• Dieback starting at leaf tips and progressing downward.
• Premature aging, making plants more vulnerable to pathogens.

Inspection tips:

• Scout regularly for mealybugs on grass leaves, stems, soil surface, leaf litter and under cow patties.
• Focus on unmanaged areas such as fence lines, ungrazed patches, and roadsides.
• Look for fluffy, white, waxy, or “fuzzy” insects on blades and stems.
• If plants appear unhealthy and insects match this description, investigate further.

“Early identification is critical, and we need every producer’s eyes on the ground,” Miller adds. “We are working diligently with our federal and state partners to determine how to best combat this novel threat and stop it in its tracks.”

If you observe suspicious symptoms or insects matching the descriptions above, contact TDA at 1-800-TELL-TDA immediately.

For more about pasture mealybug, download the factsheet.