September 2003 Soybean rust, the dreaded soybean plant disease that first appeared in Brazil in 2001, is moving north. Through checkoff-funded diagnostic tools and research, U.S. soybean farmers hope to bust rust and protect the U.S. soybean crop. The United Soybean Board (USB) hosted a symposium on the disease this summer at the American Phytopathological Society (APS) meeting in Charlotte, N.C. The goal of the symposium was to provide an update on current soybean rust research and educate other plant scientists on the disease. “It’s not a question of if this disease will enter the United States, but when,” said USB Production Chair Bryan Hieser, a soybean farmer from Minier, Illinois. Hieser said that soybean rust is a fungus that spreads by spores that move through the air. The disease originated in Asia and Australia. In 2001, rust was identified in the Western Hemisphere, in Brazil and Paraguay. Last year, the disease was identified further north in the Motto Grosso region of Brazil.

Soybean fields infected with rust may appear yellow, as evident in this picture of a heavily infected field in Zimbabwe.

“Through our checkoff, U.S. soybean farmers are taking a proactive approach to fighting this disease,” said Hieser. “USB first approved soybean checkoff funding for rust research over a year ago, in December 2001.”

The checkoff-funded research includes screening of existing varieties and exotic germplasm to find sources of rust resistance, identifying management recommendations for controlling the disease when it enters the United States and the use of weather models to help predict the spread of rust.

“We have already screened close to 3,600 lines for rust resistance in a two-stage process. Of those, 79 lines appear to have some tolerance to the disease,” said Reid Frederick, Ph.D., coordinator of the checkoff-funded rust research underway at the U.S. Department of Agriculture’s Agricultural Research Service (USDA-ARS) Foreign Disease-Weed Science Research Unit (FDWSRU) in Ft. Detrick, Md. The varieties are screened for resistance in the special Biosafety Level 3 containment facilities at the FDWSRU in Ft. Detrick.

“We have also planted U.S. varieties in rust-infected counties and are collaborating with scientists in those countries who are conducting tests for the disease,” said Frederick. “In addition to soybean checkoff funds, we have also received over $1 million in funds from ARS to sequence the two rust pathogens. And the Department of Energy is matching those funds.”

In May of 2002, the soybean checkoff was responsible for organizing a critical meeting that brought together soybean rust researchers, like Dr. Frederick, with representatives from the USDA’s Animal and Plant Health Inspection Service, the Cooperative State Research, Education and Extension Service, and the American Soybean Association to decide on the role each of these organizations would take to prepare the United States for soybean rust.

“Shortly after that meeting, USB and the soybean checkoff developed diagnostic guides for soybean rust that were distributed to farmers, crop consultants, county and university extension agents, plant pathologists and others,” said Hieser.

The checkoff-funded rust diagnostic guide and the U.S. Soybean Diagnostic Guide, which includes information on rust, are both available online at www.unitedsoybean.org. To order a printed version of these guides contact Osborn & Barr Communications at (888) 235-4332.

Farmers who think they see symptoms of soybean rust in their fields are encouraged to contact their local county extension agent or university plant disease diagnostic center immediately.

from Production Quarterly
The United Soybean Board
Copyright 2003 The United Soybean Board