Released: June 14, 2001

New Practices Urged for Keeping Karnal Bunt at Bay

MANHATTAN, Kan. – Karnal bunt disease has never been found in Kansas and like wheat growers statewide, a Kansas State University scientist wants to keep it that way.

"By now, I suspect that everybody has heard that there is an outbreak of Karnal bunt in Texas," said Bob Bowden, plant pathologist with K-State Research and Extension.

The fungal disease typically causes minimal yield loss and is no threat to human or animal health, but it can impart a fishy odor to the grain.

With harvesting equipment moving north out of Texas, Kansas growers are urged to take steps to ensure that any equipment entering their farms is free of residue that could infect their fields. Bowden is recommending a new "Best Management Practice" for wheat producers who use custom cutters or custom seed cleaners.

"All combines, grain trucks, and trailers coming from out of state should be thoroughly cleaned before entering Kansas wheat fields," Bowden said. "This is a strong recommendation, not a legal requirement. However, it benefits growers in other ways too, as it will help prevent the introduction of weed seeds such as cheat, rye, goatgrass, and Italian ryegrass into the field."

What’s at stake is Kansas’ market share of wheat exports. About half of all wheat grown in Kansas every year is exported. Approximately 80 countries restrict the import of U.S. wheat grown in areas where the disease is found.

There are two procedures custom harvesters can use to prevent the Karnal bunt from entering the state, he said.

First, Kansas Department of Agriculture inspectors are available to supervise and certify harvest equipment cleaning for custom cutters coming from a newly-established Karnal bunt quarantine area in Texas. In late May, the disease was found in wheat in two Texas counties, Throckmorton and Young.

To satisfy certification requirements, cleaning must adhere to USDA-approved methods. Three Wichita companies have mobile, high-pressure hot water washers and steam cleaners that meet USDA standards. Telephone numbers for the companies may be obtained from the Kansas Department of Agriculture in Topeka; temporary harvest offices operated by the Kansas Department of Human Resources; or any county Extension office.

Another procedure is to use a low-pressure, high-volume water treatment, Bowden said. These steps will not result in certification, but they should prevent the disease from moving into a field. An empty combine can still hold several bushels of grain and chaff, as well as weed seeds, dust, insects and diseases, so a thorough cleaning is important, he said. "The goal is to remove all of the grain and debris to avoid contaminating the next field," Bowden said.

Bowden and Vernon Schaffer, director of the KSU Foundation Seed program, have the following suggestions for cleaning a combine:

1) Do a preliminary cleaning before you leave the old field. Clean off the feeder house and reel, open the trap doors, and run the machine until the loose grain is all out.

2) Select an area for cleaning with access to a water supply.

3) Remove the header and clean it separately.

4) Park on pavement where waste grain can be swept up and disposed of properly. You might want to tilt the combine to help drain the horizontal augers.

5) Open all access doors, traps, and elevators and remove the sieves.

6) Run the machine until the loose grain is all out.

7) Use a garden hose and nozzle to dislodge debris. Start at the front and clean in the direction that grain flows through the machine. That way if you need to run the machine to shake debris loose, you won’t re-contaminate an area you’ve already cleaned.

8) If possible, remove the concaves and wash the cylinder area. On some machines, the concaves will be difficult to remove. Try using the water to thoroughly flush them in place. Continue cleaning toward the back of the machine.

9) Clean the grain tank and unloading augers.

10) Run the machine again to shake any remaining grain loose.

11) Don’t forget to look underneath and clean debris and grain that collects on the undercarriage.

12) Dispose of waste grain, weed seeds, and debris in a landfill or bury it deeply.

"Cleaning a combine can be hazardous, so always make safety a top priority," Bowden said. "Wear proper eye protection and be especially careful when running with the access doors open."

For more information, interested persons can visit the Web site http://www.oznet.ksu.edu/wheatpage/.

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by:
Mary Lou Peter, Communications Specialist
mlpeter@oznet.ksu.edu
K-State Research& Extension News