Mysterious pest threatens Texas’ $1 billion grain sorghum crop

A tiny insect of unknown origin is posing a serious threat to the $1 billion Texas grain sorghum crop, according to Texas A&M AgriLife Extension Service experts.

The threat comes at a time when a lingering drought and market pressures suggest growers will plant a larger than normal crop this year.

“For now, we’re calling this pest the sugarcane aphid,” said Dr. Raul Villanueva, an entomologist at the Texas A&M AgriLife Research and Extension Center at Weslaco. “It was first seen last year. We’re not sure if it’s a new invasive pest or if it just switched hosts, from sugarcane to grain sorghum. But it is a serious threat to this year’s grain crop and at this time there is no proven control for it.”

An insecticide known as Transform WG was tested and found to be effective against this pest, Villanueva said. The Texas Department of Agriculture recently submitted a request to the U.S. Environmental Protection Agency to approve an emergency exemption for its use on grain sorghum to control the aphid in Texas.

It is among 10 pesticides now being tested in Texas and Louisiana for their ability to manage sugarcane aphid populations.

“We’re also looking at biological control of this insect,” he said. “It appears to have lots of natural enemies, including ladybugs, lacewings and sweat flies. But the populations of sugarcane aphids grow so rapidly, we’re just not sure how effective they will be.”

Villanueva said he will supervise the evaluation of two groups of possible candidates, lady beetles and lacewings.

The sugarcane aphid, about one-sixteenth of an inch long, was first detected in 1977 in Florida sugarcane. It limited itself to the Sunshine State until 1999 when it was found in Louisiana sugarcane, Villanueva said. While populations were well established, they did not cause major crop damage in either state.

“But then in 2013, it was discovered in grain sorghum in Texas, in the Beaumont area,” he said. “Simultaneously, it was also discovered attacking grain sorghum in Louisiana, Mississippi, Oklahoma and other areas of Texas, including the Coastal Bend and the Lower Rio Grande Valley, as well as Mexico.”

Severe damage to grain sorghum in all these areas came quickly. TRUNews