While pasture mealybug is currently not in Oklahoma, Dr. Ashleigh Faris, Oklahoma State University Extension integrated pest management (IPM) coordinator and specialist for cropping systems entomology, explains producers in the state should still remain proactive in scouting for it.
The pest, first found in Australia, was detected in Texas and Louisiana last summer and has now been found in Florida and Georgia this year. Faris explains what to know about the latest emerging invasive pest in the country.
What are pasture mealybugs? What do they look like?
Pasture mealybugs are small, measuring 2-5 millimeters as adult females. Females and nymphs are oval-shaped and have fine hairs extending from all sides of their bodies. The mealybugs are also covered in a white, powdery wax that they can secrete.
“When you walk through an infested pasture, look down on your shoes or pant legs, and you can probably see evidence of that wax,” Faris said.
Older, mated females can turn a distinct pink color. Males are winged but rarely seen.
What are the consequences for pastures?
“It can wipe out entire pastures,” Faris said.
While feeding on the plants, pasture mealybugs inject toxic saliva, weakening the grass and making it susceptible to secondary fungal infections. It can result in a catastrophic condition known as pasture dieback.
One of the first warning signs of a potential infestation is the yellowing of the leaves, which progresses to reddening, then browning in large spots of a pasture.
“We all know what our pasture should look like,” Faris said. “Right now, it can be a little tough because we’re a little drought-stressed. But if you notice something is even more severe than it probably should be, go take a closer look.”
These symptoms can often be mistaken for drought stress, nutrient deficiency or diseases.
How do I find pasture mealybugs?
Faris recommends looking around the edges of any dead spots in a pasture — rather than the center of the dead spots — because that is where the pasture mealybugs will be currently feeding.
Examine the lower leaves, near the soil surface, and inspect the thatch and root crown. Also, in recently cut hay fields, check the remaining stubble.
What should I do?
While pasture mealybug currently isn’t in Oklahoma, Faris said producers should follow the news in Texas and surrounding states. Due to their small size, pasture mealybugs move easily in the wind.
If you are in an infested field, make sure to follow good biosecurity measures and wash off or sweep your pants and shoes so you don’t carry pasture mealybugs into an uninfested area. Equipment, such as trucks and tractors, should be pressure-washed or swept off after being in an infested pasture.
Currently, the only chemical product labeled for pasture mealybugs in Oklahoma is Sefina Inscalis. Still, Faris notes this product only suppresses the pest when at low populations with little pasture damage and is not recommended for high infestations.
General pasture insecticides like pyrethroids, organophosphates and carbamates are ineffective against pasture mealybugs.
OSU Agriculture and the Oklahoma Department of Agriculture, Food and Forestry (ODAFF) are currently working together to assemble a team of experts to study and educate the public on the pest from multiple angles.
I think I have a pasture mealybug infestation. What’s the next step?
If producers in Oklahoma find unexplained pasture dieback or small, white, waxy insects in their fields, they should collect a sample immediately. Package grass clippings, wrapped in a dry paper towel, inside a sealable plastic bag.
Submit the sample to your local OSU Extension county office for shipment to the OSU Plant Disease and Insect Diagnostic Laboratory for identification.
OSU Extension and ODAFF will be tracking confirmations of the pasture mealybug in the state. For more information on the pasture mealybug, visit the OSU Extension Pasture Mealybug webpage.