The U.S. Environmental Protection Agency has granted a request from a Clemson University agency to allow farmers to apply the insecticide Transform WG to control sugarcane aphids in South Carolina sorghum fields.
The South Carolina Department of Pesticide Regulation at Clemson University requested the EPA approval as the tiny, tan-colored pests attacked in droves last year after first being found in South Carolina in 2014. In addition to injuring or even killing grain sorghum plants, sugarcane aphids secrete a sticky substance that can clog and damage harvesting equipment.
Some farmers reported a total loss of sorghum yield due to sugarcane aphids in 2015, said Francis Reay-Jones, an entomologist at Clemson’s Pee Dee Research and Education Center in Florence.
South Carolina farmers harvested around 14,000 acres of grain sorghum valued at more than $5.3 million in 2012, according to the latest U.S. Department of Agriculture data. The grain is used for animal feed and has gained popularity because it is relatively drought resistant and has low input costs.
These sugarcane aphids likely can not survive a South Carolina winter, so they must migrate from warmer states each year during the growing season, Reay-Jones said. They reproduce very rapidly once here, however, he said. The pests were first spotted last year in June.
“If it’s anything like it was last year, growers will need to scout fields at least once a week after aphids are detected and use timely applications of insecticide,” Reay-Jones said.
The EPA approval allows growers to apply the pesticide Transform WG twice per year, up until April 8, 2017. Because the ingredients can be toxic to bees, applications are prohibited when wind speeds exceed 10 miles an hour and must be made with medium to course spray nozzles.
Foliar applications may be made at a rate of 0.75 to 1.5 ounces per acre. Retreatments are prohibited within 14 days of initial application.
Growers are encouraged to apply the product either before 7 a.m., after 7 p.m. or when the temperature drops below 55 degrees.
“Transform WG is a much-needed product and we are happy the EPA supported our request. It should be a useful tool for South Carolina sorghum growers in their battle against sugarcane aphids,” said Steve Cole, director of regulatory services at Clemson.
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Growers can also apply Sivanto, an effective insecticide with slightly longer residual activity than Transform WG, Reay-Jones said. Growers are encouraged to rotate insecticides, if possible, so pests do not build resistance to specific treatments.
Transform WG has a shorter pre-harvest interval (14 days) compared to Sivanto (21 days), so Transform can be a better fit when late season infestations occur, he said.
At the Pee Dee REC, meanwhile, Reay-Jones is conducting a trial study to determine which varieties have the most tolerance to sugarcane aphids.
He is also conducting trials to quantify the benefit of insecticide seed treatments, to develop sampling plans and economic thresholds to help growers determine when to apply insecticides on tolerant and susceptible grain sorghum varieties.
