Soybean rust has yet to appear in Nebraska, but that doesn't mean area farmers aren't aware of the crop-destroying fungus that made its first appearance in America earlier this year.

Potential for soybean rust was among the topics covered at Friday's Crop Protection Clinic at the Holiday Inn Express in Beatrice. The clinic, which was hosted by the University of Nebraska Cooperative Extension, also covered herbicide additives, soybean aphids, Bt corn management, weeds to watch in Roundup Ready systems and key areas of alfalfa and wheat crop protection.

Soybean rust is a fungus that causes defoliation in soybean plants, reducing yields. Rust-infected leaves eventually turn yellow and fall off, causing plants to have lower seed weight and fewer pods and seeds. Characterized by brown or reddish brown spots on the leaves, it can destroy a crop in less that a month. The airborne parasite has caused crop losses of 10 to 80 percent in some parts of the world.

Spores probably blew up from South America in Hurricane Ivan, and were first detected in Louisiana in November, according to University of Nebraska plant pathologist John Watkins, who presented the soybean rust seminar to about 30 farmers and commercial ag suppliers and service providers. Since then, the disease has been found in several gulf states and as far north as Missouri.

Some fungicides can be effective in managing soybean rust, Watkins said, but only if applied before the disease infects a crop or immediately after it appears. Research is ongoing to develop rust resistant varieties of soybeans.

Because soybean rust pathogen needs a living host to reproduce, it will probably infect other species of hosts in the winter in the warmer climates of the southeastern United States. Winds could carry it north when it gets warmer, as has happened in the past with wheat rust spores carried up from Texas, said Paul Hay, Gage County Extension educator.

"That does happen, and it does happen with some frequency," Hay told the Beatrice Daily Sun. "When it hits, it hits, and that's a problem."

Soybean rust pustules form on the underside of lower leaves of the plant. Unlike wheat rust, which is orangish and rubs off on boots and pants, soybean rust spores are more brownish in color.

Watkins said farmers who think their crops may be infected with soybean rust should contact their local Extension office or their state plant diagnostic lab.

"We're all in a learning curve," he said. "We really don't know what's going to happen."

On the Web

www.cropwatch.unl.edu