Veterans of the cotton industry have plenty of stories to tell about insect control – or the lack thereof – in the early 1990s.
Pyrethroid resistance was emerging in tobacco budworm and cotton bollworm in the eastern Cotton Belt. Out west, pink bollworm was nearly uncontrollable. And growers from coast to coast were questioning their future in cotton production.
In those same years, a new technology was carefully tucked away under evaluation in research plots throughout the Belt. Twenty years ago, that technology – Bollgard, the first Bt trait for cotton – was commercialized, and cotton production has never been the same.
“Timing is everything,” recalled Keylon Gholston, Deltapine cotton products manager. “In 1995, in certain areas across the Cotton Belt, growers just could not control tobacco budworms. The worms were so resistant to pyrethroids, and growers didn’t really have any other options.
“Bollgard came in at a great time,” he continued. “It allowed cotton growers to have protection in their fields 24 hours a day, seven days a week. And even though we had to overspray Bollgard in 1997 and 1998 for bollworms, it was only one or two sprays versus the 15 or more we had been doing.”
Ron Smith, Extension entomologist with Auburn University, didn’t realize the impact the technology would have when he began working with it in the early 1990s.
“In 1995, I actually went on record as saying we could no longer grow cotton in Alabama without some new technology,” he said. “The Bollgard technology saved the cotton industry in Alabama. I don’t believe we would have had many acres planted to cotton in 1996 without it. Roughly 77% of our acres went to that technology the first year. It’s almost unbelievable to adopt something new and, to that point, unproven on a wide scale the first year.”
In Alabama and other southern states, the Bollgard introduction coincided with the Boll Weevil Eradication program. As Gholston recalled, those events changed the two biggest pests in the southern Cotton Belt.
“We had to spray at least once a week – sometimes twice a week – for boll weevils pre-eradication,” he said. “And you couldn’t stop those treatments when you had to start spraying for bollworm or budworm. We were continually spraying, and the cost of production was skyrocketing. Plus, we were losing yield if we weren’t spraying, because worms were sub-threshold and still feeding. And if we were spraying, we were losing yield, because we couldn’t get 100% control.”
In addition to season-long protection, Bollgard also gave growers more predictable insect control costs. The BWEP provided a planned treatment system to eliminate cotton’s original major pest from the fields.
Solving an Untreatable Problem
The story was similar in the western Cotton Belt.
“Controlling pink bollworm was such a significant challenge, that growers were wondering about the future of cotton after the 1990 season,” recalled Peter Ellsworth, professor, IPM coordinator and director of the Arizona Pest Management Center at the University of Arizona’s Maricopa Agricultural Center. “What was even worse was that everything we had to spray for pink bollworm was antagonizing the entire system. There were just so many negative consequences of the harsh control measures we had to take that Bt cotton was like a miracle.”
At that time, pink bollworm control relied on an adulticidal program to prevent moths from laying eggs on bolls. Once the eggs hatched, the emerged larvae drilled into the interior of the boll within hours without being killed. It was, as Ellsworth described, an extremely inefficient means for controlling pest populations.
“The best we could ever really do was 50% control of pink bollworm with conventional insecticides,” he said. “We were really on a treadmill that was not sustainable.”
Ellsworth also worked with the Bollgard technology before commercialization. “We could feel it was going to be a revolution with all of the efficacy and regulatory trials we had been running. It was the beginning of the creation of an environment where we could use selective materials to control other pests and start to let growers better manage the system itself through conservational biological control,” he said.
Today, pink bollworm has been effectively eradicated in Texas, New Mexico, Arizona, California and Northern Mexico. According to Ellsworth, Bt cotton was the cornerstone for that program.
“You couldn’t have picked a better system in which to demonstrate the safe use of GM technology and its benefits to society by increasing the safety of our production systems.”
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