Chilli Thrips Attack Houston Plants

Chilli thrips, a new invasive insect pest, is causing severe damage to ornamental plants throughout the Houston area. And Hurricane Ike may have spread the pest farther, beyond the region, said Dr. Scott Ludwig, Texas AgriLife Extension Service entomologist and integrated pest management specialist.

The insect, only 1/16-inch long, is known to attack plants in at least 40 plant families, including many foundation plants in the landscape, Ludwig said.

“In Texas, ornamentals are the only plants they’ve been found on so far, but they have the potential to attack many other plants, including vegetables, blueberries, cotton and peanuts,” he said. “The most common plants we’ve seem them on so far have been roses – all types, including types that were previously thought to be tolerant to pest problems.”

Ludwig also has identified chilli thrips damaging cleyera, ornamental sweet potatoes and begonias in the Houston area.

Chilli thrips are usually detected in the landscape by the distinctive damage they do to plants while feeding. Chilli thrips “rasp” away developing plant tissue with their mouth parts, then suck juices from the wound. In response, leaves, buds and fruits may turn bronze in color, Ludwig said. Additionally, leaves may curl up and become distorted. Many infested plants become stunted and lose leaves or drop buds.

Control of chilli thrips is not difficult but requires persistent treatment, Ludwig said. “Though the pest is easily killed with insecticides, we have not found any insecticides that provide long-term preventive control,” he said. “Eliminating roses or planting something else may not be a solution since this pest has such a large host range.”

To date, chilli thrips infestations have only been verified in Harris and Montgomery counties, Ludwig said. “But with the pest being so small, hurricane-strength winds could have easily blown them farther north.”

Ludwig, one of the lead researchers of a national U.S. Department of Agriculture chilli thrips task force, currently is working to develop integrated pest management techniques specifically for the insect.

Those who think they may have an infestation may get help one of two ways, Ludwig said. They may visit a website that Ludwig maintains at http://chillithrips.tamu.edu or contact the AgriLife Extension office in their county. Contact information for county offices can be found at http://county-tx.tamu.edu.