Orondis Ridomil Gold SL Fights Black Shank in Tobacco

The Syngenta fungicide made a stellar debut in 2016, proving its value as a key ingredient in growers’ resistance-management programs.

Orondis Ridomil Gold SL Fights Black Shank in Tobacco
North Carolina grower Donnie Boyette employs three-year rotations across the 1,700 acres he farms with his brother Brent. Moving into the 2016 season, they planned to grow about 225 acres of tobacco in an operation that also includes production of corn, soybeans, sweet potatoes and cotton. Of those tobacco acres, there were eight in particular that concerned him. A small field had proven itself prone to outbreaks of black shank disease.

“The last two times we had tobacco in that field, we had terrible disease pressure,” says Boyette, who farms in the eastern part of the state. Their most recent attempt encountered particularly gruesome results. “Probably half of it died,” he says.

But 2016 also marked the first year on the retail market for Orondis® Ridomil Gold® SL fungicide, which offered a new mode of action for fighting black shank in tobacco. Boyette weaved it into his program.

“To be completely honest, I was surprised by the control,” says Boyette, especially given the circumstances in which it was applied. “It worked like a charm.”

Virulent Disease

Black shank is a soilborne fungal disease that can strike throughout a plant’s development, beginning at the seedling stage. The disease is extremely durable; it overwinters in the soil as chlamydospores, which can survive up to six years. Once germinated, the fungus attacks roots and invades plant wounds, leading to rotting roots and crowns. Above ground, growers with infected acres will witness wilting, along with chlorosis and necrosis of leaves, followed by the death of their plants.

"The key to Orondis is that it is one leg of a three-legged stool: crop rotation, disease-resistant strains and fungicides,” Teeter says. “Without all three, you’ve set yourself up for failure."

Ken Teeter
“Black shank can be a devastating disease,” says Ken Teeter, a Syngenta agronomic service representative, who notes that black shank doesn’t waste its time in wreaking havoc. “It’s a pathogen that attacks very early.”

Ridomil Gold SL has long been a No. 1 go-to fungicide for growers looking for black shank control. Pairing it with Orondis creates a game-changing program.

“It gives growers a double hammer,” Teeter says. “It’s a beautiful combination of two chemicals.”

New Mode of Action

Orondis Ridomil gives growers a double hammer against black shank in tobacco.

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The active ingredient in Orondis, oxathiapiprolin, is not cross-resistant to any other fungicide. It is the only active ingredient in Fungicide Resistance Action Committee (FRAC) Group 49 and offers built-in resistance management, when included in a season-long oomycete disease control program.

For 2016, Boyette deployed Orondis Ridomil Gold SL in the transplant water, then followed it with Ridomil Gold SL on its own at first cultivation and an additional fungicide at lay-by. “Orondis is great as part of a piggyback treatment system,” he says, noting that he plans to continue using it in 2017.

Boyette’s strategy is the ideal one, Teeter says, as it allows Orondis “to get into the root system and protect the plant right away.”

Prior to its arrival on the market, Orondis went through years of university tobacco-based trials. The University of Georgia, Clemson University, North Carolina State University and Virginia Polytechnic Institute and State University are among those institutions that tested real-world applications of the product.

For resistance management, researchers recommend a single application of Orondis Ridomil Gold SL, as part of an overall black shank program. Although its use in transplant water is highly recommended, growers may also leverage it at first cultivation or lay-by, depending on the needs of their program.

“The key to Orondis is that it is one leg of a three-legged stool: crop rotation, disease-resistant strains and fungicides,” Teeter says. “Without all three, you’ve set yourself up for failure.”