Deep inside a sugarcane field in Port Allen, Louisiana, LSU AgCenter entomologist Blake Wilson and two student workers pushed past green and yellow stalks at the field's edge and found cane that had turned completely brown. The farm is one of many across the state now infested with the pasture mealybug, an invasive insect first spotted by Louisiana crop consultants last year, according to an LSU AgCenter report published Oct. 1.

The discovery comes as Louisiana's grinding season gets underway. For many growers, the harvest is the first real test of how badly the pest has hurt yields, because damage inside a standing field is hard to measure until cane reaches the mill.

The stakes reach beyond farm gates. Sugarcane is Louisiana's largest crop by acreage and revenue, and the state now produces more cane sugar than any other in the country.

A Tiny Sap Feeder With Outsized Damage

Mealybugs are small, soft-bodied insects coated in a white, waxy fuzz. They feed by piercing plant tissue and sucking sap, which drains the plant of nutrients. The pasture mealybug, known scientifically as Heliococcus summervillei, is oval and fluffy with long rods of wax extending from its body, and it feeds only on grasses, a group that includes sugarcane, pasture grasses and lawn turf.

Young mealybugs, called nymphs, do most of the damage. According to LSU AgCenter identification guidance, the insect passes through four nymphal stages, most feeding happens in the first two, and adults are not thought to feed. Early-stage nymphs are very hard to spot, especially in dense cane canopies with low populations.

In Louisiana fields where the insect was found, cane developed a severe yellowing known as yellow canopy syndrome and suffered heavy yield losses. LSU researchers caution that the mealybug's feeding is associated with that yellowing, but the insect has not been confirmed as its direct cause.

The pest was first confirmed in Vermilion and Iberia parishes in late 2025 after consultants Nick Daigle and Ryan Viator noticed yellowing canopies, and USDA scientists verified the species. A June 19 update carried by Louisiana Farm Bureau News added West Baton Rouge Parish, where the detection occurred near the Mississippi River in Port Allen. The AgCenter now describes West Baton Rouge as one of the most severely affected parishes.

Harvest Season Brings the First Real Yield Test

LSU AgCenter sugarcane specialist Kenneth Gravois said the full picture will not be clear for weeks. "It's just hard to know how the pasture mealybug will affect yield," Gravois said in the AgCenter report, adding that recovery at the mills is also uncertain until harvest is well along.

Wilson has seen the worst of it firsthand. "Some fields I've seen this year aren't even going to be harvested," he told RFD-TV this summer, describing those fields as a complete crop loss.

Early mill results have been mixed but somewhat encouraging. Some initial loads processed at a St. Martinville mill showed less damage than growers had feared, according to local reports from a Sept. 25 visit by U.S. Agriculture Secretary Brooke Rollins.

The national forecast reflects that uncertainty. USDA economists projected Louisiana's 2026-27 cane sugar output at a record of about 2.27 million short tons, raw value, but trimmed overall U.S. cane sugar projections by 0.6% in August in part because of mealybug infestations and drought, Farm Progress reported.

Federal Funding and Few Proven Treatments

During that Sept. 25 visit to the Louisiana Sugar Cane Cooperative in St. Martinville, Rollins announced a $500,000 rapid-response grant to LSU and designated the pasture mealybug a priority pest for USDA's Plant Pest and Disease Management Program next fiscal year. She called the insect "a serious threat not only to sugarcane growers here in Louisiana," Acadiana News First reported, noting farmers in Florida, Texas and Georgia also face it.

The grant will fund work with the University of Florida and USDA's Sugarcane Research Unit in Houma to measure yield impacts, test treatments, identify resistant cane varieties and train growers. The anxiety in the industry is real. John Hebert of the Louisiana Sugar Cane Cooperative said growers have had "a pit in their stomach" this season, KLFY reported.

Treatment options remain limited. LSU AgCenter has said all Louisiana cane varieties are thought to be susceptible and has advised against pyrethroid insecticides, which have been reported to increase infestations in Texas pastures. In Florida, where the pest spread to 15 counties this year, UF/IFAS reports that no insecticides are specifically labeled for it, though the EPA granted a crisis exemption allowing one product on sugarcane there.

The evidence picture is still early. Most of what is known comes from field observations in Louisiana, pasture dieback in Texas, and research in Australia, where the pest is native. Researchers have not yet published controlled Louisiana yield-loss studies, so damage estimates should be treated as preliminary.

Ranchers, Homeowners and Growers Are All on Watch

Sugarcane growers in the affected parishes carry the most immediate financial risk, especially smaller farms that cannot absorb a lost field. But because every grass species is a potential host, cattle ranchers with improved pastures and homeowners with turfgrass lawns are also in the pest's path. Texas reported pasture dieback in 22 counties in 2025, though Louisiana has not yet confirmed the pest in pastures.

LSU says the insect can spread through wind, storms and contaminated equipment. That makes harvest season, when heavy machinery moves between fields, a higher-risk period for spread.

Warning signs include patches of yellowing, reddening or browning grass that look like drought stress, and small white, fuzzy insects on the undersides of leaves. Growers should clean harvesters and trucks between fields and use extra caution before moving sod, hay or grass from Vermilion, Iberia or West Baton Rouge parishes.

Suspected infestations in sugarcane should be reported to Blake Wilson at the LSU AgCenter or to the Louisiana Department of Agriculture and Forestry at [email protected]. Homeowners who see suspicious lawn damage can contact their parish extension office before buying any pesticide, since untested products may waste money or worsen the problem.

Next steps hinge on harvest data. Mill reports through the four-month grinding season will show how much sugar was lost, and the USDA-funded research is expected to produce a practical management guide. The bottom line is that the pest is established and spreading, its true cost is still being counted, and careful scouting and equipment hygiene remain growers' best tools for now.

What Readers Want to Know

What is the pasture mealybug?

It is a small, white, fuzzy insect native to Australia and parts of Asia that feeds on the sap of grasses, including sugarcane, pasture grasses and turf.

Where has it been found in Louisiana?

LSU AgCenter has confirmed it in sugarcane in Vermilion, Iberia and West Baton Rouge parishes, and it says many farms across the state are now infested. It has also been found in Texas and Florida.

Why is the sugarcane turning brown?

Infested fields show severe yellowing that can progress to browning. Researchers say the mealybug's feeding is associated with these symptoms, but it has not been confirmed as the direct cause.

Will this raise sugar prices?

USDA still projects a record Louisiana cane sugar crop, though it trimmed national cane sugar projections slightly. There is no official estimate linking the pest to retail sugar prices.

Can it damage my lawn or pasture?

Potentially. All pasture and turfgrasses are considered possible hosts, though Louisiana has not yet confirmed the pest in pastures. Report suspicious damage to your parish extension office.

How can growers slow its spread?

Clean equipment between fields, avoid moving grass or hay from infested parishes, skip pyrethroid insecticides, and report suspected infestations to LSU AgCenter or the state agriculture department.