EPA finalizes ban on use of chlorpyrifos
On Aug. 30, the EPA published a final rule banning all use of the pesticide chlorpyrifos. The agency took this action in accordance with an April court order from the United States Court of Appeals for the Ninth Circuit.
The ban takes effect Feb. 28, 2022.
According to UGA researchers, chlorpyrifos is used to control insects that inflict damage on several key Georgia crops.
Chlorpyrifos is the only product recommended for control of lesser cornstalk borer in soybeans. It is also used to combat peanut burrower bugs and rootworms in peanut fields and is recommended for control of cutworms in cotton but is used on a small percentage of cotton acres.
“We are fortunate that these pests do not occur in every field every year, but when they are present, their injury can result in significant economic loss,” said UGA Associate Professor of Entomology Dr. Mark Abney. “A load of peanuts at the buying point will be downgraded from [a quality grade of] segregation 1 to segregation 2 if 3.5% or more [of the peanuts in a load] have insect damage. The economic impact of that reduction in grade is huge.”
Abney said the abundant rainfall in Georgia this year is a prime example of the importance of chlorpyrifos to protect peanut crops, noting that rootworms require moist soil to survive and flourish.
“Due to the abundant rainfall we have received in 2021 we are seeing abnormally high populations of rootworm in peanut fields,” Abney said.
The state’s soybean growers will need an alternative product for their 2022 crop. According to UGA Extension Entomologist Dr. Phillip Roberts, chlorpyrifos is the only pesticide recommended to control the lesser cornstalk borer in soybeans.
“We have little information on alternatives,” Roberts said. “One potential alternative is chlorantraniliprole. We have limited data in soybean but this insecticide is used for lesser cornstalk borer control in peanut.”
Roberts said chlorpyrifos is also recommended for cutworm control in soybeans, but growers can also use pyrethroids for cutworms.
UGA Assistant Professor of Entomology Dr. Brett Blaauw said chlorpyrifos is not essential to pest management in peach orchards, but the EPA ban could be costly for Georgia peach growers.
“It is commonly used for peachtree borer, lesser peachtree borer, and scale insect management,” Blaauw said. “It is relatively inexpensive and works well, so the loss of chlorpyrifos has the potential to significantly change how producers grow peaches, especially economically.”
Blaauw said that the USDA and UGA have collaborated on research into the use of mating disruption dispensers to control peachtree borers. Additional studies have shown that placing parasitic nematodes that prey on insects at the base of peach trees may control peachtree borers. As for pesticides there aren’t many options, but novaluron has been shown to be effective for borer management.
Blaauw noted that to control scale insects, insect growth regulators and horticultural oils can be used to effectively. Those compounds are more expensive, but can also be more effective than chlorpyrifos, he said.
“The loss of chlorpyrifos has the potential to hurt the peach industry, but thankfully we still have the tools needed to continue to grow fantastic peaches in the Southeast,” Blaauw said.
Chlorpyrifos is also used by Georgia onion, pea and sorghum producers.
The EPA’s final rule was published in the Federal Register on Aug. 30. It can be read in its entirety at www.federalregister.gov/documents/2021/08/30/2021-18091/chlorpyrifos-tolerance-revocations.