Thrips have become public enemy No. 1 for many cotton farmers with tarnished plant bugs becoming a bigger and bigger pest in many parts of the Cotton Belt.
Thrips and plant bugs are the gifts that keep on giving because insecticide resistance is becoming an issue with many growers having to make multiple applications to achieve control of both pests.
Plant bugs are popping up in places they haven’t been before, while thrips are often the biggest yield robbing pests for many cotton producers.
Cotton farmers are hoping for new tools to help battle both thrips and plant bugs. And at the Deltapine NPE (New Product Evaluator Summit) at the Marriott in New Orleans Dec. 14, Bayer revealed its new biotechnology trait, ThryvOn Technology, designed to protect cotton from both pests.
ThryvOn is the first biotechnology trait designed to provide season-long protection to the whole cotton plant against tarnished plant bugs and thrips species. Pending regulatory approval, ThryvOn is expected to be commercially available in the next few years — the early 2020s.
Scientists across the Cotton Belt have conducted research on the new biotechnology trait since 2014 and say it shows promise as a new tool to battle thrips and plant bugs.
At the NPE Summit, a panel of entomologists from the University of Georgia, the University of Tennessee, Mississippi State University and Texas A&M University discussed the challenges of thrips and plant bugs and how ThryvOn technology can help.
In Mississippi and across the Delta, plant bugs have become a consistent yield robbing pest over the past few years. Dr. Jeff Gore, a Mississippi State University entomologist at the Delta Research and Extension Center in Stoneville, said Delta farmers in some cases have to spray for plant bugs up to 15 times per season with eight to nine applications very common.
“The one consistent pest we see a yield response to in our environment is the tarnished plant bug. Even missing one to two sprays in a bad year is going to mean yield loss and we’ve seen it happen,” Gore said at the NPE Summit.
In Georgia, plant bug pressure hasn’t been a problem as it has been in the Delta, but thrips are a different story. Dr. Phillip Roberts, Extension entomologist at the University of Georgia, said basically 100 percent of the state’s cotton will be infested by thrips.
He said some type of preventive action against thrips is needed and he sees the ThryvOn technology as a good potential preventative tool for thrips. He said preventive control is a must to battle thrips in Georgia.
Seed treatments have worked well, but Roberts noted farmers have seen erosion of control due to resistance. One of the ways Georgia farmers have combatted resistance is with timely foliar sprays.
“We’ve added a trip to do it right to fully preserve yield. We like to be back in at first leaf, and we have a small window to truly preserve that yield potential,” Roberts said.
In Tennessee, Dr. Scott Stewart, professor of entomology and IPM Extension specialist at the University of Tennessee, said if thrips weren’t controlled, they would likely be the No. 1 yield robbing pest year in and year out in the state.
“In our environment, it’s very common to spray at least one time foliar for thrips. Because of that and because we have consistent pressure, we’re starting to see resistance issues. We’re seeing resistance to thiamethoxam and neonicotinoids. Recent data shows orange back thrips might be developing resistance to acephate,” Roberts said.
Stewart said the ThryvOn technology will definitely save a thrips spray. He calls it “excellent technology” for controlling multiple species of thirps.
“We still have to develop some knowledge of this product as it gets released on a larger acreage. A lot of the activity of this product is repellency or avoidance. It’s very strong on tobacco thrips and definitely a factor with tarnished plant bugs. We didn’t think and nobody thought the technology killed adult tarnished plant bugs. But we received improved square retention in a lot of our plots. If we’re not killing them, they must not be feeding on them,” Stewart said.
In Texas, resistance to seed treatments means farmers are having to make more sprays to control thrips. “In most situations, with the resistance, we’re having to spray for thrips earlier than we did previously,” said Dr. David Kerns, professor and statewide IPM coordinator at Texas A&M University.
Kerns noted that the thrips spray applications don’t line up with herbicide applications which means an extra trip and additional costs to growers.
Thrips pressure does vary in different geographical regions of the Lone Star State. Kerns said certain areas constantly experience thrips pressure, while in other areas thrips don’t present a problem. He estimated that roughly 1.5 million cotton acres across Texas are treated for thrips, a significant amount.
“I think when we figured out the costs of applications across the state associated with thrips injury, it comes up to $20 million to $25 million. Thrips are a significant pest for us,” Kerns said.
As with thrips, when it comes to tarnished plant bugs in Texas, pressure varies by geography.
“There are some areas in south Texas where we get some pretty bad plant bug pressure. You move up the coast and it plays out, but you will still have them out there. And as you move west the species changes, so you go from regular tarnished plant bugs to western plant bugs, a different species, but they do the same thing,” Kerns said.
In Tennessee, plant bugs also vary by region, but Stewart noted that virtually every acre in the state gets treated for tarnished plant bugs.
“We probably average three or four applications per year. As we get closer to the Mississippi River and the Delta environment, we struggle more with tarnished plant bugs. The other thing we are struggling with, particularly in the Mid-South because we spray so much, is insecticide resistance. Things that used to work when I got to Tennessee 16 to 17 years ago don’t work near as well now. We need some new chemistries,” he said.
