A tiny insect recently discovered in Florida is creating a big problem for ranchers in Polk County.The yellowing of the plant was the first indication that I saw that was an issue going on that was spotty, said David McCullers.W ATCH: New invasive insect found in 16 Florida counties spreads to Polk County ranch Florida pasture mealybug threatens ranchland in Polk CountyThe rancher said he began noticing sections of pasture at Crooked Lake Ranch in Frostproof, turning yellow and producing less grass for his cattle.It really was not an area that I thought I would ever see under this kind of stress, said McCullers.McCullers initially thought the problem was a lack of nutrients in the soil; instead, he learned that an invasive insect was the culprit.The pasture mealybug is a small, white, oval-shaped insect that feeds on grazing grasses by injecting a toxin that can eventually kill the plant. McCullers said the insect has already damaged about 100 acres of grass. He has already spent thousands of dollars on insecticide, but the treatments were not successful.We didnt really accomplish what we thought we were going to accomplish with that round of spray, and that was a good $9000 worth of trial that I had not budgeted for, McCullers said. The pest has already been linked to widespread pasture damage in Australia. It was first found in Texas in 2025, where it quickly spread statewide, and has since been detected in Louisiana. Florida confirmed its first case in South Florida in late May 2026. Since then, infestations have been found in 16 counties, and researchers are continuing surveys to see how far the insect has spread.The level of damage were seeing and the spread were seeing here and the same thing in Texas, the level of spread that they saw last year and this year, indicates that it was probably here before. It just went unnoticed, said Marcelo Wallau, UF/IFAS Forage Extension Specialist.Researchers are studying several treatment options, but they said slowing the spread of the insect is the best course of action for now.We have a few insecticides that are labeled now plus a few others that are not yet labeled that were testing. Hopefully well have more information on the efficacy of those insecticides soon, Wallau said. Until then, ranchers say they will continue fighting to protect the grass their cattle rely on.It could devastate the ranching industry as we know it because if you continue to get out of control bugs that take away your grass, thats our livelihood,McCullers said.If you suspect your field is infected, take pictures and fill out the UF/IFAS Pasture Mealybug Report form and send samples to the FDACS Division of Plant Industry. ...read more read less