Research ties heat to mealybug feeding and pasture damage

Sadie Harley

Scientific Editor

Andrew Zinin

Chief Editor

High temperatures change how mealybugs feed, and that could help explain why some pasture mealybug infestations do far more damage than others, according to early findings from Texas A&M AgriLife Research scientists.

The study, led by doctoral student Ashley Zavala in the lab of Thomas Chappell, Ph.D., an epidemiologist in the Texas A&M Department of Plant Pathology and Microbiology, focuses on mealybug feeding behaviors under a range of environmental conditions.

These findings could eventually help ranchers more precisely manage the invasive pest that continues to spread across Texas and impact native and regionally adapted improved grasses.

Pasture mealybug threatens forage, livestock production

Pasture mealybug was first confirmed in Texas in July 2025 and has since expanded to 114 counties across the state, according to Texas A&M AgriLife Extension Service entomologists. It is a serious threat to the forage and grazing lands that support Texas' $15.5 billion cattle industry and other pasture-based livestock operations.

The pest has also been reported in Florida, Georgia and Louisiana, and scientists are concerned it could impact other agricultural production, including sugarcane and rice.

In pastures, immature mealybugs feed on plant sap and inject toxins that weaken the grass, often leading to a condition known as pasture dieback. In severe infestations, fields can turn brown, thin out dramatically or die entirely. The invasive pest impacts a broad mix of native and improved warm-season grasses, from bermudagrass and bahiagrass to bluestems and other key forage species.

Sensors turn mealybug feeding into usable data

To measure how mealybugs feed under different conditions, the team uses a technique called electropenetrography, or EPG. The method attaches a sensor to the insect and the plant to record feeding activity as a waveform, which Chappell compares to reading an electrocardiogram.

"It's tedious work, but it's exciting to know that what we are learning could make an impact and help people deal with this serious pest threat," Zavala said. "If we can better understand what changes the way these insects feed, that's a piece of the puzzle that can help guide management."

Chappell's lab is applying the technique to a related mealybug species feeding on pepper plants, but he sees a clear connection to pasture mealybug. He said forecasting tools that consider feeding behavior, plant stress and susceptibility, and weather patterns could help growers more precisely time their pesticide applications—much like existing weather-driven modeling has done for other pests.

Intelligent agriculture systems could further hone how the data are processed as well as the accuracy and effectiveness of those forecasting tools.

"Mealybugs were relatively underexplored because, before pasture mealybugs, they had not been as big a threat to ag producers," Chappell said. "EPG paves the way for new insights about pest-plant interactions in specific environmental factors."

Tying seasonal factors to feeding behavior

The findings so far have shown that heat and environmental stress change mealybug feeding behavior and could help explain why some infestations are more severe, Chappell said.

Mealybugs feed by piercing plants and drawing out fluids, typically the sugar-rich sap in the phloem, though they can also tap the xylem, the tissue that carries water. When temperatures rise, Chappell said, insects may drink more xylem to stay hydrated.

Heat also increased how often the mealybugs salivated in the phloem. That matters because saliva carries the enzymes and toxins that damage plants, so hot conditions could mean more harm from the same number of insects.

Solving the pasture mealybug puzzle

The early results could provide key insights into the broader puzzle that pasture mealybug has presented to scientists and producers.

AgriLife Research and AgriLife Extension scientists across the Texas A&M College of Agricultural and Life Sciences, including the Department of Plant Pathology and Microbiology, Department of Entomology, Department of Soil and Crop Sciences, Department of Rangeland, Wildlife and Fisheries Management and the Department of Agricultural Economics, are aligned as research disciplines that will work collaboratively on pasture mealybug targeting the pest from every angle.

So far, they have linked pasture mealybug population growth to factors such as canopy density, heat, humidity and rainfall and continue to pursue answers regarding forage plant susceptibility and recovery.

By understanding factors that contribute to damaging infestations, the research teams are working to identify a suite of management tools and science-based recommendations that forage producers and ranchers can depend on to target the pest and its vulnerabilities. Chappell and Zavala's work adds another layer by looking at how weather conditions shape the behavior of individual insects.

"Our entomologists are tracking where pasture mealybug is, how populations move and how to control it, and forage researchers are examining which forage varieties hold up better under their stress," Chappell said. "Ashley's work connects these by demonstrating how weather affects feeding intensity."

Next steps

Texas A&M AgriLife formed the Emerging Pest Task Force of subject matter experts charged with responding to agricultural and natural resource threats from pest incursions. The task force's current priority is pasture mealybug, and its members recently testified before members of the Texas Legislature on New World screwworm and pasture mealybug in Austin.

Provided by
Texas A&M University

Citation: Research ties heat to mealybug feeding and pasture damage (2026, November 3) retrieved 4 November 2026 from https://phys.org/news/2026-11-mealybug-pasture.html