Bill Ryan/The Gazette Buckeystown farmer Nick Maravell gets his tractor ready Tuesday.

In south Frederick County, soybean farmers Nick Maravell and Chuck Fry are braced for the potential arrival of a destructive leaf fungus called Asian soybean rust.

"It requires a very careful monitoring process," said Maravell, owner of Nick's Organic farm in Buckeystown. "A lot of diseases on soybean plants look like rust."

Asian soybean rust, which spreads by airborne particles, originated in China. It spread to Australia and was detected in South America in 2001. Last year it blew progressively north, damaged a wealth of crops in Brazil, and was confirmed in the United States in Louisiana in November.

Since then, soybean rust has been found in more than 12 states: Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, Missouri, South Carolina, and Tennessee.

This summer, as temperatures warm, it could spread to northern states, including Maryland.

What is soybean rust?

If it becomes widespread, soybean rust could cause large crop and economic loss to soybean growers and industries. It has destroyed as much as 80 percent of crops in untreated fields abroad, according to the U.S. Department of Agriculture.

Spores thrive in temperatures ranging from 59-85 degrees Fahrenheit, and would not normally survive in the soybean belt in the Midwest and the Mid-Atlantic region, with frequent winter frosts. But spores can live year-round in the warmer southern states, which then could provide a launching platform for the disease to blow north each season.

Maravell, an organic farmer whose fields on Buckeystown Pike are used for research by the U.S Agricultural Research Services in Beltsville, suspects soybean rust will arrive late this season or next year.

"Soybean rust is going to get blown up to this area," Maravell said. "If it becomes more of a pandemic, it springs up all over the place."

Though the fungus poses no threat to humans, it is one of the most destructive soybean diseases, according to a 2004 research report co-authored by Reid Frederick, a microbiologist at Fort Detrick in Frederick.

Infected plants have reddish or tan spores and pustules on their leaves and mature more rapidly than uninfected plants.

At Fort Detrick's USDA Agricultural Research Service, Foreign Disease-Weed Science Unit, where Frederick works, more than 3,600 lines of soybeans have been tested for resistance to rust. About 2 percent of those have demonstrated resistance.

Getting ready for the fight

To ready for the disease, farmers can hand-check plants' leaves and follow reports on the whereabouts of disease findings. Maravell said the challenge for farmers is knowing when and whether to treat crops for it.

"It's going to be a very difficult timing issue," Maravell said. "If you go in to early, you won't get as big of a bang for your buck. If you go in too late, you lose everything. It's not an easy disease to deal with."

Reluctant to add to his production cost, Maravell said he will treat this year only after research results confirm the effectiveness of organic treatments or when he learns of nearby outbreaks, such as in a Virginia field.

He said organic soybean farmers are more challenged in fighting soybean rust than conventional growers, who have the option of using the six fungicides approved by the USDA. Applying the fungicides would disqualify the harvest from being certified as "organic."

Maravell, who is also vice chair of the Maryland Organic Food and Farming Association, said he is drafting a letter to USDA asking for an emergency exemption to allow organic soybean growers to use approved fungicides.

With about 25 acres of soybeans among his produce variety this season, Maravell said organic treatments are too limited and their effectiveness too under researched to help organic farmers fend off soybean rust.

Organic farmers may turn only to copper-based fungicides, which wash off with rain, or bio-fungicides, which frequently do not survive through dry hot spells common to Maryland summers, Maravell said.

Without effective treatment, Maravell said his roughly $30,000 worth of revenue from wholesale of the beans could be wiped out.

"In my case, the soybeans are sold as fresh vegetables," Maravell said. "If there's rust on the pod, it would make the products less marketable or not marketable."

Valuable commodity

One of Frederick County's top five commodities, soybean crops were valued at more than $4 million in 1997, according to the Maryland Farm Bureau. Only poultry, cattle and dairy outranked soybeans.

In Point of Rocks, Chuck Fry, owner and operator of Rocky Point Farm, said he will spray fungicides when the disease reaches North Carolina. A member of the Frederick County Agriculture Business Council, Fry said soybean rust is just the latest of a long list of diseases that plague soybeans.

"They all start out terrible," Fry said of soybean diseases. "But it will be fine in the end. You just have to wait and see."

Combating the rust could add more than $5,000 to Fry's expenditures ­ from $10 to $12 per acre for fungicides for his 500 acres of soybeans, which he grows for feed for his dairy cattle. Armed with fungicide options, he is less worried about severe crop damage.

"We have sprays that will take care of it," Fry said. He plans to hand-inspect his plants for rust this year. "Once you find it, you have three to four days to spray."

In Maryland, production of soybeans has declined by about 40 percent in the last decade from reported yearly revenues of about $100 million in 1996 to about $62 million in 2002, according to the Maryland Department of Agriculture.

Soybean planting begins in mid-May.

Soybean rust

* Asian soybean rust is a new disease that could hurt local soybean crops this summer.

* Soybean farmers should check their plants' leaves for reddish or tan spots or bacteria pustules. Farmers who detect those symptoms should immediately call the Cooperative State Research Education and Extension Office at 301-694-1594.

* Diagnostic guides are available at www.unitedsoybean.org or www.usda.gov/soybeanrust.

Source: U.S. Department of Agriculture