Humans may be culprit in latest South Texas invasive insect problems

September 15, 2015 by Rod Santa Ana, Texas A&M University
Dr. Raul Villanueva, an entomologist at the Texas A&M AgriLife Research and Extension Center at Weslaco, inspects tomato and sesame plants for damage from the tomato bug. Credit: AgriLife Communications photo by Rod Santa Ana

An insect considered beneficial in many parts of the world is causing havoc on vegetable crops in South Texas, according to a Texas A&M AgriLife Extension Service entomologist in Weslaco.

"We first found this insect, Nesidiocoris tenuis, commonly referred to as N. tenuis or the tomato bug, in commercial field crops in the Rio Grande Valley in October 2013," said Dr. Raul Villanueva. "But now we're finding it in abundant numbers on tomato crops throughout the area. It's causing fruit drop on both tomato and sesame crops. It's now well-established here."

For the first time, growers are having to spray insecticides this year to control N. tenuis because of their extremely high populations, in some cases hundreds per plant.

"What's really interesting about this insect is how it got here," Villanueva said. "I suspect that somebody illegally brought a bottle of these insects and intentionally released them either in Mexico or the U.S."

The tomato bug is originally from India and is commercially available in Europe to control whitefly populations in greenhouses.

"The illegal release was likely made to control whiteflies in greenhouses," he said. "They are a good predator of whiteflies and work very well. They prey at all stages, but especially as nymphs. But outside greenhouses they can cause a lot of problems, like we're seeing here now. So, it's a two-edged sword."

Dr. Raul Villanueva points to two tomato bugs so small they are barely visible on a sesame plant. Credit: AgriLife Communications photo by Rod Santa Ana

The tomato bug is considered zoophytophagous, meaning it feeds on a variety of prey.

If the release occurred in Mexico, Villanueva suspects they naturally migrated to South Texas. If they were released in California, they likely made their way here aboard tomato seedlings, tiny plants shipped to the Lower Rio Grande Valley in trays that growers use to start their crops.

On tomatoes, Villanueva said they cause flower abortion by feeding on the plant, reducing nutrients and causing the flower to drop, which reduces yields.

In sesame crops, they lay eggs on leaves and feed on pods. They cause necrotic patches on plant stems where they feed and lay eggs. They can also feed on the plants' pollen

"Sesame is a relatively new grain crop to the Rio Grande Valley," Villanueva said. "It's harvested for use on buns and as flour for cookies. It is grown practically year round here, and this year the area saw its largest sesame crop, some 15,000 acres."

The tomato bug has also been found on okra, squash and peppers but damage has so far been minimal in these crops.

"For now, pyrethroids have been providing control, but insecticides are expensive and we just don't know how long it will continue to be effective. That's why we're evaluating other insecticides for efficacy."

Danielle Sekula-Ortiz, the AgriLife Extension integrated pest management agent in Weslaco who first detected the tomato bug in South Texas sesame crops, said she was concerned when she found it because she knew they could damage tomatoes in the same way they were damaging sesame.

"They were becoming quite abundant and feeding heavily," she said. "So we met with about 30 sesame growers where Dr. Villanueva and I were able to inform them of N. tenius, or the tomato bug, and made recommendations on spraying for them. They are now well-established, so we expect to continue seeing them in the sesame growing season. We also have plans for more research to help our growers."

On the positive side of the double-edged sword, Villanueva suspects the bug may be reducing whiteflies on the South Texas cotton crop, though it hasn't actually be found on cotton yet.

"For the last two years, whiteflies have not been a serious problem in our cotton crops," he said. "We can't be sure there is a direct correlation, but because N. tenuis is so well-established here, they may be affecting whitefly populations in cotton."

Explore further: Farmers markets driving tomato research

Related Stories

Farmers markets driving tomato research

February 7, 2013

The emergence of farmers markets in the Lower Rio Grande Valley has led to new research that shows planting dates affect the productivity of organic tomatoes, according to an expert at the Texas A&M AgriLife Research and ...

Whitefly, tomato growers find truce in new Texas variety

December 5, 2011

The whitefly in Texas may be sending up a surrender flag to tomato processors in the state thanks to a Texas AgriLife Research scientist developing a new variety that resists the virus spread by this pesky insect.

Recommended for you

The powerful meteor that no one saw (except satellites)

March 19, 2019

At precisely 11:48 am on December 18, 2018, a large space rock heading straight for Earth at a speed of 19 miles per second exploded into a vast ball of fire as it entered the atmosphere, 15.9 miles above the Bering Sea.

OSIRIS-REx reveals asteroid Bennu has big surprises

March 19, 2019

A NASA spacecraft that will return a sample of a near-Earth asteroid named Bennu to Earth in 2023 made the first-ever close-up observations of particle plumes erupting from an asteroid's surface. Bennu also revealed itself ...

Nanoscale Lamb wave-driven motors in nonliquid environments

March 19, 2019

Light driven movement is challenging in nonliquid environments as micro-sized objects can experience strong dry adhesion to contact surfaces and resist movement. In a recent study, Jinsheng Lu and co-workers at the College ...

Revealing the rules behind virus scaffold construction

March 19, 2019

A team of researchers including Northwestern Engineering faculty has expanded the understanding of how virus shells self-assemble, an important step toward developing techniques that use viruses as vehicles to deliver targeted ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.