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Issues: U.S. Department of Agriculture Attacks Karnal Bunt

(The following is adapted from "Karnal Bunt - A Strange Sounding Wheat Disease with Serious Implications," produced by USDA's Animal and Plant Health Inspection Service staff and available on the Internet at: http://www.aphis.usda/gov/oa/bunt/feature/txt.)

Washington -- The Karnal bunt task force headquartered in Phoenix, Arizona, is wrapping up the initial phase of combating this fungal disease of wheat. "The discovery of Karnal bunt this spring kicked off a comprehensive effort to identify contaminated areas and take actions to prevent spread to areas free of this wheat disease," said Terry Medley, administrator of the U.S. Department of Agriculture's (USDA's) Animal and Plant Health Inspection Service (APHIS). "These actions were also designed to protect our U.S. wheat export market. We are working closely with producers, millers, shippers, exporters, state officials and other interested parties to sort through all the issues surrounding Karnal bunt," he continued. "I am optimistic that we can control and contain this disease and develop a strategy that will allow us to reach our goal of eventually eradicating Karnal bunt in the United States."

The USDA Karnal bunt task force was activated immediately after the March 8 confirmation that Karnal bunt had been detected for the first time in the United States. Scientifically, Karnal bunt, or partial bunt, is caused by the smut fungus Tilletia indica Mitra and is spread by spores. Typically, only a portion of the kernel is affected; that's why the disease is sometimes called partial bunt. It presents no human health risk and affects only wheat, durum wheat and triticale (a hybrid of wheat and rye).

Damage from Karnal bunt is twofold: (1) infected plants produce less grain; and (2) flour made from bunted -- or "smutted" -- kernels can be discolored with an unpleasant, fishy odor. Although overall crop losses caused by Karnal bunt might not be severe, a number of countries restrict imports of wheat because of Karnal bunt, and thus it could affect U.S. grain exports. According to Frank Coolidge of USDA's Foreign Agricultural Service, the United States accounts for nearly 30 percent of world wheat exports. "In calendar year 1995," he said, "U.S. wheat exports were valued at $5.5 billion."

First Found in India Where did this fungus come from? According to Steve Poe, a plant pathologist with APHIS, Karnal bunt was first reported in 1931 in the Indian state of Haryana in wheat-growing areas near the city of Karnal, from which the disease gets its name. "Since then," he said, "it has been found in all major wheat-growing areas of India, as well as in Pakistan, Iraq and Afghanistan. Karnal bunt may have been present in Mexico since 1970. And," he continued, "we know it has been well established in some areas in northwestern Mexico since 1982. Until recently, the disease was not known to exist in the United States."

But on Tuesday, March 5, 1996, Joel Floyd, a plant pathologist with APHIS' Plant Protection and Quarantine (PPQ) program at Nogales, Arizona, received a package from Ron Ykema, a seed analyst with the Arizona Department of Agriculture (ADA). Ykema had spotted an odd-looking kernel during a routine germination test on a durum wheat sample at a seed dealership in Yuma, Arizona, and sent suspicious-looking seeds to Floyd. Floyd sent a sample containing 20 suspect seeds to the USDA's Agricultural Research Service (ARS) Foreign Disease-Weed Science Research Laboratory in Frederick, Maryland.

The Tell-Tale Signs of Smut On Wednesday, the ARS Frederick lab received the sample; spores were visibly present on the wheat kernels. Normal testing protocols would take 10 days to germinate the spores for proper identification, but APHIS and Arizona officials needed a faster response. So the visible spores in all 20 seeds were scraped out to extract enough DNA for a molecular biology test using a process known as PCR (polymerase chain reaction). Late on Thursday, ARS scientists confirmed that the spores were Karnal bunt. On Friday, March 8, a telephone conference call was held between ARS personnel, APHIS representatives, and ADA officials, to confirm that Karnal bunt had been found in U.S. wheat.

Later that day, USDA issued a press release announcing the discovery and, in accordance with the International Plant Protection Convention, began informing its trading partners of the detection through the Food and Agriculture Organization of the United Nations and the North American Plant Protection Organization.

Task Force Mobilized By Monday, March 11, APHIS officials had activated a rapid response team to begin quarantine and survey work. This group formed the heart of the Karnal bunt task force. The immediate job was to trace the source of infected seed lots, identify all Karnal bunt-infected premises, disseminate up-to-date information to local wheat growers and wheat industry officials, and enforce regulatory actions. Initially, the infection appeared to be limited to durum wheat of specific varieties. Also, most of the contaminated wheat was certified seed, which meant that there was a good "paper trail," making the work of tracing shipments much easier.

A first step was placement of emergency action notices (EAN's) on infected properties, seed, farm equipment, planted wheat and soil associated with the infected wheat. This effectively restricted movement of materials that might spread the spores. Meanwhile, a group of state, federal and university experts met in Phoenix to update an existing APHIS Karnal bunt action plan. They examined the outbreak and then tailored survey, regulatory and control measures.

Extraordinary Emergency Declared On March 21 Secretary of Agriculture Dan Glickman announced that he had signed a "Declaration of Extraordinary Emergency." This allowed USDA to take a wide range of actions to control and eradicate the fungus, including compensating farmers for losses and giving the Department authority to impose quarantines within a state.

On March 25 a federal area quarantine for Karnal bunt was placed on the entire state of Arizona; on Dona Ana, Hidalgo, Luna, and Sierra Counties in New Mexico; and on El Paso and Hudspeth Counties in Texas. Further investigation tracked contaminated wheat to California, and on April 19, the federal quarantine was enlarged to include Imperial County and the eastern part of Riverside County.

Another shipment of contaminated wheat was traced to Montana, but, fortunately, the seed was still in storage facilities there and officials were able to destroy it before it was distributed for planting. A few other isolated contaminated lots have been identified, but again, officials were able to minimize disease spread.

Risk-Based Quarantines The federal quarantine and APHIS' procedures are flexible and risk-based, according to Medley. "Our quarantine boundaries were determined by the area put at risk by distribution of contaminated seed," he said. "With risk-based regulations and procedures, the movement of grain from regulated areas to specific markets or for specific uses is allowed under carefully controlled conditions."

On March 26, Secretary Glickman signed a "Declaration of Emergency," under which he transferred $24.7 million from the Commodity Credit Corporation for fiscal year 1996 to help with Karnal bunt program activities. On April 1, crop destruction orders were issued for wheat farmers in Texas and New Mexico who had fields planted with contaminated durum wheat seed. These producers were paid $275 per acre plus $25 per acre plow-down costs.

According to Chuck Schwalbe, an APHIS PPQ official, once potentially infected wheat starts heading out (when kernels emerge in the plant) -- as was the case in Arizona and California -- the best strategy for containment is to let it go to harvest and then handle it in a way to minimize disease spread. "Plowing down headed-out wheat could inoculate the soil with Karnal bunt spores," he said, "and make the disease more difficult to eradicate." Schwalbe noted that Karnal bunt spores can survive in the soil for four to five years. "This means," he said, "that infected wheat fields may have to be planted with alternative, non-host crops for the next five years. As with many diseases, the job of control and eradication is not a short-term project."

Pre-harvest Sampling What is being done to contain the disease where potentially infected wheat is allowed to ripen? "We have a comprehensive pre-harvest sampling program underway," said Donald F. Husnik, PPQ deputy administrator. "Samples are being taken from each field of the 1996 wheat crop in the quarantined area at the time of harvest. Wheat that tests negative in the field and again before shipment can move under limited permit to designated processing facilities for milling, for the production of animal feed, and for export consistent with country of destination requirements. "These two tests substantially reduce, but do not eliminate, the risk that this wheat is contaminated," Husnik noted. "APHIS is entering into compliance agreements with millers under which they will handle this negative-tested wheat in a way that will not spread Karnal bunt. Flour presents a negligible risk, but additional treatment is required to reduce the risk of spreading disease from mill by-products that are used for animal feed. APHIS also has approved an additional protocol that allows limited movement of untreated millfeed under regulated conditions specified by the state of destination," he said. "Other states may choose not to allow this because their situation is different."

Wheat that tests positive for Karnal bunt cannot be moved outside the quarantine area. Options for infected wheat include its (1) shipment to a flour mill within the quarantine area (flour can move freely once it is processed; mill by-products have to be heat-treated or moved under restriction); (2) use as animal feed provided it is subjected to heat treatment; (3) destruction; or (4) movement to export if the country of destination will accept it.

By the beginning of August, with sampling virtually completed, pre-harvest testing of wheat in Arizona and California was indicating only low levels of infection. In Arizona, 4,710 wheat fields had been sampled and tested, with Karnal bunt found in only about 4.3 percent of the acreage tested. In California, infection was lower -- about 2.6 percent of the acreage tested. Pre-harvest testing of about 200 fields in New Mexico and Texas was negative.

In both Arizona and California, the infected fields appear to be concentrated in a few "hot spots." Based on this and other information, on June 27, quarantines were lifted from the entire counties of Yavapai, Conconino, Navajo, Apache, Gila, Greenlee, and Santa Cruz, and from portions of Mohave and Pima counties in Arizona; from portions of Hidalgo, Luna, and Sierra counties in New Mexico; and from a portion of Hudspeth County in Texas.

Protecting Export Markets Concurrent with field operations in the U.S. Southwest were efforts coordinated from Washington, D.C., to protect U.S. wheat exports. Like the United States, a number of countries restrict or prohibit wheat imports from areas where Karnal bunt exists. One of the first steps after confirmation of the disease was a series of conference calls to U.S. agricultural attaches around the world.

"Our purpose was to inform them of the Karnal bunt situation in the Southwest and that the vast majority of our wheat was produced in areas where the disease did not occur," said Chuck Havens, head of PPQ's phytosanitary issues management team. "We wanted our people to have complete information so that they could deal effectively with plant health officials in foreign countries. Then came the hard work of negotiating agreements with our trading partners on the conditions under which they would accept U.S. wheat," Havens said. "At the outset, 20-plus wheat-importing countries had listed Karnal bunt as a quarantine pest. If you counted the nations of the Russian Federation and Independent Republics separately, that number ballooned to around 35.

"One of the more effective arguments that we were able to make is that surveys for Karnal bunt in a number of states over the years were all negative. Currently, we have resolved Karnal bunt certification for virtually all outstanding U.S. wheat sales," he continued, "enabling our export shipments to proceed in a normal manner. We are continuing negotiations with those few countries where problems remain."

National Survey Starts APHIS has allocated $3 million to begin a two-year national survey to determine the actual extent of the Karnal bunt outbreak. This survey, which has already begun, involves sampling wheat elevators in each wheat-producing county in the United States several times during the year. "Negative results from this survey will be used to verify to our trading partners that grain is from areas free of Karnal bunt," Havens said.

More than 20,000 samples will be tested from some 2,100 counties, according to PPQ's Dave McNeal, who has been working on the survey design. "The survey is voluntary on the part of country elevator operators," he said, "but we anticipate good cooperation because of USDA's announcement that it will provide compensation in the event that Karnal bunt is discovered." To date, all survey tests have been negative.

Multi-Agency Effort The Karnal bunt project has been a multi-agency effort involving a large mobilization of personnel and resources. While APHIS PPQ employees took the lead in setting up the task force, they worked side-by side with state employees from Arizona, New Mexico, Texas, and California. Seasonal tobacco graders from USDA's Agricultural Marketing Service (AMS) were used to help with pre-harvest field sampling. Officials from USDA's Foreign Agricultural Service negotiated with foreign countries to keep our wheat flowing overseas.

USDA's Grain Inspection, Packers and Stockyards Administration (GIPSA) provided valuable service in sampling grain for interstate shipment and, in some cases, so it could be tested for export. In addition, GIPSA representatives are providing composite samples of all wheat shipments loaded at Western (Great Lakes) ports to be transshipped through Canadian transfer elevators. APHIS and the Canadian Government are testing the composite samples for Karnal bunt as a condition for entering Canadian port facilities.

Coordination of the activities of the various agencies involved with Karnal bunt within USDA lies in the hands of Paul Drazek, special assistant to Secretary Glickman. Drazek meets regularly with agency representatives to review the Karnal bunt program and harmonize activities where more than one agency is involved.

Keeping Everybody Informed Keeping everybody informed is one of the biggest challenges in Karnal bunt. APHIS established a Karnal bunt "home page" on the Internet's World Wide Web ( to provide accurate and timely information on the disease and what was happening. More than 8,800 "visits" to the home page have been recorded since mid-March. Basic information about the disease, quarantines, and Karnal bunt program activities also was issued in press releases, fact sheets, and special public updates. In addition, Secretary Glickman and other top USDA officials have been holding regular meetings with a variety of state officials and industry groups.

Most recently, USDA sponsored five public forums to provide additional opportunities to comment on Karnal bunt regulations and other aspects of the program. The first of these forums, held in Washington, D.C., on July 17, attracted more than 60 participants. Additional forums were held on August 13 in Kansas City, Missouri, August 14 in Phoenix, Arizona, August 15 in Imperial, California, and August 20 in Las Cruces, New Mexico.

Over-Reaction? Did USDA over-react when Karnal bunt was found, as some have claimed? Is this really just a minor disease that's no worse than some others we already have in this country? "If we are being criticized for doing too much, I would say only that this criticism would pale in comparison to what we would be hearing if we had done nothing or had taken inadequate actions," Medley said. "While some may argue that Karnal bunt is not serious and is something that we can live with, the quarantine implications alone demanded that we take decisive actions. Maintaining a $5.5 billion export market was critical for the affected industries and states.