You can't pick up a farm-related publication these days without reading something regarding Asian soybean rust. With the official start of the hurricane season and one tropical depression already, many farmers are concerned about the status of the disease and our plan for the remainder of the season.

Is the Mid-South prepared for soybean rust? With help from the Arkansas Soybean Promotion Board, the Arkansas legislature and USDA, the Arkansas Soybean Rust Working Group began preparing in early January, basing our plan on lessons learned in South America.

Since Arkansas has such a wide planting window for soybeans (mid-March through early July), we began planting sentinel plots March 14 and continued until May 16. Rather than using different planting dates at each location, we decided to use a wide range of maturity groups (2.9 through 5.8). With the difference in planting dates coupled with the maturity groups chosen, Arkansas should have a wide array of soybean growth stages throughout the year for sampling.

When all was said and done, Arkansas had 37 soybean sentinel plots representing 33 soybean-producing counties. In addition we have identified 13 kudzu sites to monitor.

This is quite an accomplishment considering the task set before us. This spring, Alan Beach, Extension soybean program associate, committed countless hours to getting the plots in. He's to be commended.

We have also established weather stations in Crittenden, Prairie, Chicot, Miller, Poinsett, and Yell counties to monitor environmental conditions throughout the season. Data such as air temperature, relative humidity, rainfall, wind speed/direction and leaf wetness will be recorded every 30 minutes. Data from all stations will be downloaded every seven to 10 days and results will be posted on our soybean rust Web site (www.aragriculture.org/cropsoilwtr/soybeans/Rust/weather/default.htm).

With the help of Rick Cartwright, Extension plant pathologist, and other members or the Arkansas Soybean Rust Working Group, the following information provides an update on current and future soybean rust research efforts as well as funding support for these projects:

  • Very limited funding (up to $37,500) has been promised by USDA/APHIS in support of monitoring national sentinel plots established in Arkansas (15). The funds will be released through the Arkansas State Plant Board.

  • Backup temporary personnel for the Plant Disease Clinic and the sentinel monitoring program have been hired.

  • Conventional PCR is now available at the Plant Disease Clinic and real-time PCR is available for the clinic at the University of Arkansas-Fayetteville (UAF) for confirmation of Asian soybean rust.

  • Testing of the Envirologix Elisa Kit for Asian soybean rust detection continues. Results are promising.

  • All Section 18 fungicide approvals expected for 2005 — including Quilt and Headline SBR, and Orius 3.6F (another brand of tebuconazole) — have been received by Arkansas. An additional seven fungicides applied for may not be available until 2006. These include Quadris XTRA, Punch, Charisma, JAU6476, Impact, metconazole and Operetta.

  • Efficacy testing for all registered fungicides has been planned and some plots have been planted. Control of soybean rust and other diseases, yield and seed quality will be assessed.

  • Testing for slow-rusting resistance has been designed and seed has been obtained. Thirty-eight early Group 4 varieties and 12 late Group 4 varieties were included.

  • Spore trapping and forecasting projects — in collaboration with regional and national researchers — have begun using backup personnel at the University of Arkansas in Fayetteville and field personnel in eastern Arkansas. Arkansas will provide expertise in reading the spore trap collections for the southern United States.

  • If the Asian soybean rust is re-established in the state during the summer, greenhouse and growth chamber studies are planned for the fall

  • The State of Arkansas has appropriated $150,000 for Asian soybean rust research and Extension efforts. Federal funding does not appear likely. The state funds will allow us to finish high priority 2005 projects established using checkoff funds.

With a major portion of our early-planted crop reaching reproductive stages, many want to know what action to take. Right now, fungicide applications for soybean rust alone are not recommended. Historically, Arkansas has treated up to 1.5 million acres with a foliar fungicide for diseases such as frogeye leafspot and aerial web blight. Current fungicide decisions should be based on these diseases and not on soybean rust.


Chris Tingle is the Extension agronomist for soybeans with the University of Arkansas Cooperative Extension Service. This article was prepared by Tingle and other members of the Arkansas Soybean Rust Working Group.