Last year, Asian soybean rust was a problem to confront and watch in the Southeast. This year, with ASR overwintering in Mexico and Texas, soybean producers must fret about a second avenue of attack for the disease. ASR could ride in from the Southwest on the Delta's prevailing wind pattern.
“That's a major concern,” says Jamie Nielson, Valent's Domark brand manager. “The winds could easily carry ASR into the Mid-South and on into the Midwest, where the majority of soybean acres are. That puts states like Arkansas more at risk for ASR. With that, growers should be as concerned as or more concerned than they were last year. (They need) to have a good plan in place to defend against this devastating disease.”
Valent is pushing Domark, currently a Section 18 product, as the prime fungicide solution to deal with ASR. There are three key points Nielson makes about Domark:
It's both preventive and curative.
It's safe for soybeans and, unlike some other fungicides, doesn't cause any phy-to-concerns.
It provides at least 20 days of residual control.
“As part of the residual component, it actually protects the new trifoliates on the plants,” says Nielson. “In many regions, new trifoliates pop out after the R-1 stage of plant development. Domark has an ability to move throughout a plant and helps protect those new trifoliates.”
Many plant pathologists agree that the two products best for ASR as curatives are tebuconozole (Folicur) and tetraconozole (Domark).
“Those are third generation chemistries — the latest technology in triazole chemistry — the two that producers look to,” says Nielson. “In our trials, Domark has provided better frogeye control…Domark is a proven product and has been used in Brazil for over four years.”
To fight ASR, the best time to treat soybeans with Domark is first bloom, R-1. Such a treatment would be preventive.
“If you're targeting secondary diseases or looking to go after, say, frogeye, then the best time to spray is R-3.”
Does the product do better being applied with ground rigs or airplanes? “We tested both in 2005 and found both very effective. Ground control may have a little bit better effectiveness. But overall, both are effective tools for controlling ASR.”
Does Valent have enough Domark in the right locations to deal with a potential 2006 ASR outbreak? “That's a million dollar question. It will depend on how severe ASR is. If it occurs in Texas and Mexico, as it could, and moves through Louisiana into Mississippi and Arkansas (that's a large amount of soybeans to treat). Arkansas is growing around 3 million acres of soybeans alone. If those need to be treated, that's a big chunk.”
The big concern is if ASR reaches Illinois and Iowa where, combined, there are some 20 million acres of soybeans. “I think (Mid-South) growers will have good supplies of (Domark). That's because it's highly likely rust will occur there before it hits the Midwest. We have some great customers that cover large regions and we'll be working with them if rust comes. We'll be working with them to move product accordingly.”
Valent continues to look at options for mixing Domark with other chemistries. “We're looking at mixes with other fungicides as well as insecticides. There are more insects becoming problematic in soybeans — stink bugs, aphids in the Midwest, mites. So we're studying pre-mix and tank-mix options.”