ST. LOUIS (DTN) -- Gus Lorenz is bracing for a tough insect control landscape in 2016, after the EPA announced a ban last week on sales of sulfoxaflor, the active ingredient in Dow AgroSciences' Transform WG insecticide.
"This is a bad situation for our cotton and sorghum growers," the University of Arkansas entomologist told DTN. "It will increase the cost of production and it will be more difficult to keep insects under control."
More northern growers also use Transform to fight the soybean aphid, but they have good alternative insecticides, said Iowa State University entomologist Erin Hodgson. Cotton and sorghum growers, however, will be forced to resort to older and less environment- and bee-friendly chemicals and risk the rapid development of insect resistance, Lorenz warned.
Transform was registered in 2013 to control piercing and sucking insects like aphids and plant bugs in soybeans, canola, cotton and other crops. After an outbreak of a new pest called the sugarcane aphid in sorghum, the EPA had also issued Section 18 emergency use exemptions for Transform to 13 states by 2015.
Now the insecticide is off the market indefinitely, after the EPA bowed to a federal court decision that ruled that the agency had registered sulfoxaflor without sufficient evidence that it did not harm pollinators. The court ruling was the result of a lawsuit by the Pollinator Stewardship Council, a coalition of beekeepers and beekeeping trade groups.
Dow has announced its commitment to work with EPA to supply the necessary data, and the industry group National Sorghum Producers has vowed to fight for its re-registration. However, for now, Transform is off the market and growers will have to adjust, Lorenz said.
BATTLING THE PLANT BUG IN COTTON
In the past few years, Transform had become the preferred insecticide to control tarnished plant bugs, the cotton industry's most costly pest. Older alternative chemistries, such as pyrethroid and organophosphate insecticides, have been largely compromised by insect resistance, Lorenz said.
"We definitely don't need to lose a tool," said Bob Walker, who farms cotton near Somerville, Tennessee. "In a bad year, we may spray six to eight times for plant bugs and in that situation, you need to have some ability to mix your chemistries up, so this worries me."
"We think Transform saved us one or two applications," Lorenz added. Without it available, he estimated cotton growers may spend $18 to $36 an acre more to control plant bugs in 2016.
In the ruling against sulfoxaflor, the court concluded that leaving the insecticide on the market without more research presented an unacceptable risk to the pollinator population. However, Lorenz is worried that the ban on Transform presents the bigger threat to pollinators.
"If you put [sulfoxaflor] on a scale of all the insecticides we currently use, it's below average as a toxin to bees," he said. "The battle to get rid of Transform is kind of ironic because in the end it will result in growers having to spray more often and use more products that are more toxic to bees for control of plant bugs."
Transform was also easier on the beneficial insects that populate crop fields and help farmers control other pest populations like aphids, Walker said. "They're not looking at the whole picture," he said of the ban's proponents.
RISKING RESISTANCE IN THE SUGARCANE APHID
In 2014, Texas sorghum grower Josh Birdwell could hardly keep up with the sugarcane aphid. He sprayed Transform twice and still struggled with the pest at harvest. "We probably needed to spray at least three times," he told DTN. Even after record rains in 2015, the aphid still required treatment, he added.
Sorghum growers will now have to control this aggressive new pest with one insecticide, a product from Bayer called Sivanto. Given the aphid's rapid spread and its ability to produce multiple generations in a season, resistance is inevitable, Lorenz said.
"This is the worst insect you could deal with, from a resistance standpoint, with one product," he said. "If we have another aphid year like this past one, we'll likely see resistance by the end of 2016 and definitely by 2017."
At $2.50/oz., Sivanto is also more expensive than Transform, particularly at the higher rates often needed to combat bad aphid infestations, Birdwell said. In an effort to lessen his reliance on insecticides, he said finding aphid-resistant hybrids will be his top priority when selecting seed this year. But when the aphid shows up next spring, he and other growers will have to pull out the sprayer.
"People are worried," he said. "We try not to be totally reliant on them but chemicals are big part of what we do."
"We hope that EPA understands that we have to have another insecticide for control of this pest," added Lorenz. "We can't live with just one. That's an untenable situation."
You can find the EPA's cancellation order for sulfoxaflor here: http://1.usa.gov/….
You can read the Ninth Circuit Court of Appeals' ruling against sulfoxaflor here: http://bit.ly/….
Emily Unglesbee can be reached at firstname.lastname@example.org.
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