Aphid Relief

ROCKVILLE, Md. (DTN) -- Sorghum growers in Texas will be able to use sulfoxaflor, the active ingredient in Dow AgroScience's Transform insecticide, to control the sugarcane aphid, despite an EPA ban on the product.

The EPA has approved a request by the Texas Department of Agriculture for a Section 18 emergency exemption use of the product on up to 3 million sorghum acres in the state. (USDA predicted 2.2 million acres of sorghum would be planted in Texas in its prospective plantings report in March).

The Section 18 request was filed in December 2015 after the EPA canceled Dow's registration for sulfoxaflor after a ruling from the Ninth Circuit Court of Appeals questioning its safety for pollinators. That decision was a blow to sorghum growers, who have access to only one other insecticide that is effective against the sugarcane aphid, a Bayer CropScience product called Sivanto.

The new emergency use label for Transform in Texas addresses pollinator concerns by banning applications from three days before bloom all the way to seed set. "This product is highly toxic to bees exposed through contact during spraying and while spray droplets are still wet," the label warns. That label also recommends that growers minimize the risk to pollinators by spraying "before 7 a.m. or after 7 p.m. local time or when the temperature is below 55 [degrees] F at the site of application."

The emergency use label is effective until April 2017. Several other sorghum-growing states, such as Kansas and Louisiana, have also applied for Section 18 exemptions and are waiting to hear from the EPA.

The Texas decision bodes well for those applications, said Texas A&M entomologist Pat Porter. "It is extremely good news for all sorghum growers," he told DTN.

Controlling the sugarcane aphid with just one insecticide was almost certain to lead to rapid insect resistance, Porter explained. "Aphids are basically clones that are born pregnant and if resistant alleles exist in a population, and growers are using the same insecticide again and again, resistance will spread rapidly," he said.

Depending on when sugarcane aphid populations start building in Texas, the restriction on spraying between bloom and seed set could be a problem for some growers, Porter said.

Aphid infestations can spread rapidly across a field if conditions are right and require prompt treatment. "For example, on the High Plains last year, we picked up our first aphid colonies on June 27," Porter explained. "And by time we needed to start spraying, it was approximately two to three weeks later and a lot of the crop was at bloom."

For now, however, sorghum industry leaders are celebrating the Section 18 approval, which they had vowed to fight for as soon as Transform was taken off the market.

"The availability of Transform WG is crucial to helping sorghum farmers combat the sugarcane aphid," Tim Lust, CEO of the National Sorghum Producers, said in a press release. "We thank the U.S. Environmental Protection Agency for their approval of this important crop protection tool, which augments industry efforts to develop better management practices and resources to meet this unprecedented challenge."

You can find more information about the new emergency use label for Texas growers at Porter's blog here: http://bit.ly/….

You can see the Texas Department of Agriculture's Section 18 request to the EPA and the 387 public comments it received here: http://1.usa.gov/….

Emily Unglesbee can be reached at emily.unglesbee@dtn.com

Follow Emily Unglesbee on Twitter @Emily_Unglesbee

(PS/AG)

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