2005 Year in Review

Checkoff Research Stays On Top Of Soybean Rust

Source: Julie Toohill at (309) 663-7692

In Spring 2004, researchers said that as for soybean rust, it was not a matter of "if," but "when" it would arrive in the United States. That "when" came in November 2004, when the USDA confirmed that soybean rust disease had indeed reached the United States, first spotted in experimental fields in Louisiana. Soybean rust has been confirmed in nine other states, as of July 1, 2005, since it was first discovered on November 10 in Louisiana.

The Illinois Soybean Checkoff Board, through a coordinated effort with state and national agriculture organizations, along with state and federal government agencies, has focused on scouting, detecting and managing the disease in order to minimize the economic effects on Illinois soybean farmers and the state's agricultural output.

Soybean Rust - Soybean rust is a disease caused by the fungus Phakopsora pachyrhizi. It is most destructive in the tropical and subtropical regions of Asia and Australia. It also has been found in Africa and South America, and now has appeared in the southern United States.

Through the checkoff, U.S. soybean farmers are taking a proactive approach to fighting this disease. Nationally, soybean checkoff funding for rust research was approved in December 2001. Researchers at the University of Illinois are currently evaluating soybean germplasm for resistance genes and efficiency of fungicides.

With support by the soybean checkoff, close to 16,000 lines from the National Soybean Germplasm Collection have been evaluated for rust resistance in a two-stage process at the U.S. Department of Agriculture's Agricultural Research Service Foreign Disease-Weed Science Research Unit in Ft. Detrick, Maryland. Of those, 79 lines appear to have some resistance to the disease.

Work continues on monitoring the movement of the disease and informing soybean farmers of new developments in monitoring and management of rust with fungicides.

Management - Management of soybean rust can occur in several ways, the most effective of which are usage of resistant soybean varieties and/or application of chemical control measures. The U.S. soybean industry is taking a two-pronged approach to battle soybean rust. The short-term strategy is to evaluate and recommend fungicide and other management tactics that can minimize potential yield loss. The long-term goal is to develop rust- resistant soybean varieties through germplasm research and breeding. Checkoff funding supports management studies and strategies at both state and national levels.

Chemical Control - Chemical control using fungicides has been shown to be effective at controlling soybean rust in many countries, and may be the best short-term alternative in the U.S. until adapted, resistant soybean varieties can be released. In regions favorable to rust development, the rapidly repeating life cycle of the soybean rust fungus requires that detection be early and fungicide application be made immediately in order to effectively control the infection. Checkoff-funded research has shown that soybean rust can grow from 5% to 90% disease severity in just 21 days.

There are six crop protection substances that are approved for use on soybeans to combat soybean rust disease, with at least eight product lines for soybean farmers to purchase. Local crop service companies or local extension educators can provide that list. These substances have been tested and approved for use by the Environmental Protection Agency and are not harmful to soybean plants, the crop produced, or to humans.

Don't Overlook Other Soybean Culprits - There is no doubt that soybean rust is on the minds of most Illinois soybean farmers, but researchers warn farmers not to overlook other confirmed soybean diseases and pests that can lead to extensive yield losses.

Midwest soybean farmers lose more than $1 billion in potential yields each year to the top 20 soybean diseases and millions of dollars each year to soybean pests. Wayne Pedersen, retired plant pathologist, University of Illinois, Urbana-Champaign, and John Russin, associate dean, Southern Illinois University-Carbondale, remind Illinois soybean farmers that their checkoff dollars also have been invested in germplasm evaluation, disease characterization, and control and management development for many of the soybean pests and pathogens that affect their fields each year.

Russin and Pedersen say continuing research is extremely important to help farmers understand how to control existing pests and pathogens--such as Brown Stem Rot, Frogeye Leaf Spot, Southern Root-Know Nematode, and Phytophthora Root Rot--that expand into new areas.

Additional Resources - More information about soybean diseases can be found at:
USDA
Soybean Disease Research
Soybean Diseases in Illinois
Plant Health Initiative
VIPS
IPM

by  Editor, theCity1.com
July 18, 2005