EPA has granted a Section 3 registration for the application of Domark fungicide to control Asian soybean rust and other diseases such as frogeye leaf spot and purple seed stain in soybeans.

Valent U.S.A. Corp., the company that markets Domark under an agreement with Milan, Italy-based Isagro SPA, received a series of state-by-state Section 18 emergency exemptions for Domark in the spring of 2005 and again in 2006 for control of Asian soybean rust.

The full, federal registration granted on April 13 will allow farmers to apply tetraconazole, the active ingredient in Domark, to prevent yield losses from Asian soybean rust and from frogeye, purple seed stain, brown rot and other soybean diseases.

“The Section 3 registration will give growers a tool they haven’t had before,” said Jamie Nielson, Domark product manager. “We have a great deal of information from university trials that indicate Domark provides exceptional control of other diseases along with Asian soybean rust.”

For soybean farmers, he said, Domark will “maximize harvest value, which means disease protection, ease of harvest and crop safety, resulting in higher yield and increased profit. An additional key advantage Domark has is that there are no harvest issues with green stems.”

“In university trials, Domark was consistently one of the best performing fungicides for soybean disease control,” said John Pawlak, Domark product development manager. “We saw excellent control of frogeye, the No. 1 secondary disease in soybeans — better than some of the leading triazole and strobilurin fungicides.”

Domark, which has been available under the trade name Eminent in Brazil for several years, can be used as both a preventative and curative treatment for soybean diseases, protecting existing and new growth, they said. Its systemic activity allows Domark to be quickly absorbed by the soybean leaf and evenly distributed throughout the treated leaf to ensure fast-acting control.

Asian soybean rust has proven to be a hard disease to get a handle on since it was first discovered in the United States by Ray Schneider, a plant pathologist with Louisiana State University, in November 2004.

“The southeastern states — Florida, Georgia, the Carolinas — seem to be at risk for an outbreak in some portion of the region almost every season,” he said. “So year in and year out we are likely to have the disease in those states.

The situation in the Mid-South is more variable. “The likelihood of the disease in the Mid-South may depend on whether soybean rust becomes established in Texas and Mexico,” he noted. “During a three-week period in September and October last year, we saw the disease move from Louisiana to the Missouri Bootheel to Illinois to Iowa so we know it can spread very quickly.

“My concern is that if we get a season with good moisture conditions, we could see Asian soybean rust become a serious threat to soybeans in a widespread portion of the triangle, and farmers could suffer severe losses.”

The United States probably will never be like Brazil when it comes to soybean rust. “We don’t have the year-round growing season and 100 inches of annual rainfall. We’ll be more like an Argentina with occasional outbreaks of the disease.

“It may be an every year experience in the Southeast, it may occur every two or three years in the Mid-South and on rare occasions in the Midwest. Year in and year out, we think 1 million acres could be effected, mostly in the Southeast and in Louisiana.”

The recent freezing conditions in the Mid-South and Southeast states may have hindered the development of Asian soybean rust but could also set up situations in which ASR could be more of a problem down the road.

Some growers who lost whole fields of corn to the freeze may decide to replant them in soybeans, which could expand acres of the latter. Farmers could also plant more double-cropped soybeans behind the increased acres of wheat planted last fall.

“We could see a lot more double-cropped soybeans, which could extend the window out into September and October,” said Nielson. “There are a lot of unknowns about Asian soybean rust.

“My concern is that growers will become complacent and not monitor the rust situation carefully,” he said. “The main thing is growers need to have a rust plan and a rust fungicide they can rely on.”