EPA OKs label for rice fungicide

Schultz Bruce, Groth, Donald E.

News Release Distributed 02/24/14

CROWLEY, La. – LSU AgCenter plant pathologist Don Groth said a federal label for the fungicide Sercadis has been granted for the upcoming growing season.

Groth made the announcement at the Rice Technical Working Group’s 35th meeting held recently (Feb. 18-21) in New Orleans, which was attended by more than 400 rice experts and scientists. The working group meets every even-numbered year throughout the rice-growing states to exchange research data and provide updates on their work.

The temporary label for Sercadis expired in August 2013 for use on fungicide-resistant sheath blight in rice, and rice growers had their fingers crossed that the U.S. Environmental Protection Agency would grant the full label.

Groth said the 2013 regulations allowed the use of the fungicide for any areas with the resistant pathogen. The permanent label will allow the fungicide to be used anywhere rice is grown in the South.

The fungicide-resistant pathogen continues to spread and could move into other rice-growing states, Groth said.

“If it happened here, it can happen somewhere else,” he said. “We think we have detected it further north into Allen and Evangeline parishes.”

He said the disease is spread by soil or plant material.

The continued use of the same fungicide led to the resistance, Groth said. “If you challenge the population enough and put selection pressure against it, a resistant pathogen will develop.”

The fungicide resistance developed due to a single change in an amino acid of the thousands of combinations in the pathogen’s DNA.

Sercadis at the higher rate in 2013 made the product much more effective, Groth said. The previous rate of 4.5 ounces per acre was increased to 7.6 ounces. Application is normally most effective when applied around the boot stage of rice.

“The consultants I talked with liked it,” Groth said. “They thought the rice looked like fields sprayed with Quadris when it first came out.”

In addition, the restriction on where the product can be used has been relaxed.

Groth said he is testing several new fungicides that may be available in two to three years. “There’s potential we will have resistance to Sercadis in five to six years,” he said. “If we have another product we could rotate with Sercadis, that would be the ideal situation.”

Fungicides have been used on rice since 1977, Groth said. Sheath blight in rice became a problem as more rice farmers started growing soybeans in rotation with rice, and the beans were also susceptible to the sheath blight pathogen which causes aerial blight. Before that, farmers rotated rice with pasture for cattle.

Much of Groth’s research has been accomplished with check-off money paid by farmers based on 5 cents for every 100 pounds of rice sold.

“Without this funding resource, the disease research could not have been done,” Groth said. “Getting a product like Sercadis approved by the EPA requires support from scientific data that our research provided.”

A lawsuit by a small group of farmers has successfully challenged the constitutionality of the check-off program.

“These check-off dollars are well spent on the hard work by our staff at the station,” said Steve Linscombe, resident director at the Rice Research Station. “I’ve had many farmers tell me they would no longer be in business if it weren’t for our research, and much of that work could not be done without the check-off funds.”

Bruce Schultz
2/25/2014 4:03:13 AM
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