Karnal Bunt, Where Are We Headed?

From Keith Kelly, Director of the Arizona Department of Agriculture
May 29, 1996

Arizona did not want Karnal bunt. Like the rest of the country, we did not need any more pests. Arizona did not want the boll weevil, the white fly or the Africanized bee, either.

We in Arizona are trying to figure out if KB is like the boll weevil, which we can control very well; like the white fly, which we have some small control over; or the Africanized bee, which we have little control over but have learned to live with.

The Northwest did not want TCK. The Upper Midwest did not want scab. Nobody wanted ergot or the many other diseases that can affect wheat. Are our efforts to eradicate KB as fruitless as trying to eradicate TCK, scab or ergot - while at the same time scaring off our international buyers? Or can KB be controlled as effectively as the boll weevil?

We all revere the American wheat industry. Wheat as the staff of life is depicted in Biblical verse and ancient Greek and Roman art and writings. Wheat is a way of life that holds what is best in America.

The question is what is best for the health of the entire U.S. wheat industry. The Arizona industry knows that its fortunes are tied to the national industry but the Arizona industry is only willing to make sacrifices which address the scientific reality of the disease.

Arizona did not want Karnal bunt. But it's here. What do we do now?

We worry that we are counterattacking KB using long entrenched theories about the effectiveness of slash and burn policies. Where is the precedent showing that these policies are effective against a fungus in wheat? Are these policies determined more by agency inertia and agricultural politicking than by scientific reality? Even worse, we wonder if USDA's slash and burn, zero-tolerance policies are really a Maginot line that creates overconfidence and leaves us open to unexpected catastrophe.

We have been so occupied with the logistics and tactics of the battle that we fear that few are thinking two steps ahead of a realistic strategy that can win the war. This paper evaluates three possible scenarios and possible solutions.SCENARIO #1: KB Spores are Widely Scattered and International Markets Close

Under this scenario, KB turns out to be like white fly or Africanized bee whose spread cannot be controlled. There is a very real possibility that KB spores have already been widely dispersed throughout the United States and possible Canada, according to Merritt Nelson, Head of the Department of Plant Pathology at the University of Arizona, and Robert Forster, Professor of Pathology at the University of Idaho.

Wheat seed was widely imported from Mexico before the 1983 quarantine. We found KB spores in a farm storage facility that has not stored grain in 15 years. We found KB bunted kernels in Arizona grain from the 1993 crop. KB spores may have been in earlier crops, however, we do not have any grain left from earlier crops to sample. During 1993 through 1995, many wheat breeders increased their seed stocks in Arizona during the winter and that seed was planted on thousands of acres throughout the United States and Canada. Nevertheless, there were no visible signs of KB in the United States until three months ago.

If KB spores became established outside the quarantine area, it would be nearly impossible to detect without laboratory analysis because of the weak nature of the pathogen. Remember that no farmers, marketers or customers noticed KB in any Arizona wheat. In fact, the grain we generally regarded by buyers as being of excellent quality. It took the unusual combination of a seed analyst who was also trained as a plant pathologist to find it. In the massive pre-harvest sampling program in Arizona this year, we have found only two (2) kernels that show visible signs of infection. That is, we found only two (2) partially bunt kernels in samples of over 2000 fields so far.

Burning Bridges

The most visible symptoms of the disease are seen in the international wheat markets. The USDA, in 1983, quarantined wheat from countries that have KB, specifically Mexico. We understand the United States was one of the first countries to quarantine KB but with USDA leadership, 25 countries had KB import restrictions by last March.

When the first KB was discovered by a laboratory technician in March, APHIS executed a full scale eradication program without knowing how widespread the disease was. The enormous mobilization by APHIS, of course, created enormous fears among domestic and foreign buyers of U.S. wheat. Drastic actions create drastic fears. Several countries who had no KB certification requirement in March, no do - and the number of countries is growing. In addition, the inconsistency and double standard of requiring stricter criteria for shipment to domestic mills than for foreign export was an open invitation to foreign countries to raise their standards. Italy's recent actions are a good example, APHIS, we imagine, believes these KB restrictions are justified because the foreign buyers are simply doing what APHIS would do.

Since the initial discovery, the more we look for KB spores, the more we find them. Now that USDA is looking for KB spores everywhere, are we going to find them to be widespread? Are we then going to find that the slash and burn, zero-tolerance policy toward KB has burned all of our bridges with foreign buyers? If we need to retreat from current policy, will we find ourselves trapped by spreading KB import restrictions? This scenario is where the potential for a true catastrophe lies.

USDA should be very careful not to commit itself to a battle plan in Arizona that will trap the rest of the U.S. wheat industry if KB spores are found to be present in other areas.

Zero-Tolerance Trap

We are all familiar with the ramifications of the zero-tolerance trap for carcinogens in food, the Delaney Clause. Now that technology can find one (1) spore in a sample, the ramifications of the zero-tolerance trap on international wheat markets could be dramatic. For example, if KB is widespread, even at incredibly low spore levels, the zero-tolerance trap will deny a huge amount of U.S. wheat access to a growing number of foreign markets.

There are national tolerances for ergot (less then 0.3% by weight), perhaps the most deadly small grain disease in human history. There are national tolerances for vomitoxin in scab wheat (2,000 parts per billion), a by-product of the wheat disease scab common in the Upper Midwest, which is toxic to humans. There are national tolerances for aflatoxin (20 parts per billion), one of the most potent carcinogens known to man. In veterinary medicine is the concept of critical infective dose - that is, one e.coli organism does not cause an infection.

For KB spores, there is no national tolerance even though we estimate that finding one (1) part in a 50 gram sample would still be equivalent to only half of the tolerance for aflatoxin. Remember, KB is not a human health issue.

The concept of zero-tolerance for KB spores is as unrealistic as the concept of zero-tolerance for ergot, zero-tolerance for vomitoxin, zero-tolerance for aflatoxin, or zero-tolerance for E. coli.

APHIS should establish a realistic safe tolerance level for KB spores in wheat destined for milling and feed use. FAS and APHIS should then encourage those countries that have KB import restrictions to also adopt those tolerance standards.

APHIS was the leader in implementing KB import restrictions. If APHIS cannot also lead them into making their KB import restrictions more realistic, the U.S. wheat industry will end up with a catastrophe under this scenario.

SCENARIO #2: KB Becomes the TCK [Tilletia controversa Kuhn, dwarf bunt] of the Southwest

Under this scenario, we assume that KB has not become established outside of the Southwest even if KB spores have been spread more widely. We assume that all areas with KB spores were discovered in March and April of 1996.

We also assume that KB turns out to be more like boll weevil, a pest which can be controlled or "biologically eradicated" but which cannot be scientifically eradicated to absolute zero. KB is controlled through testing and quarantine of affected land, seed regulations, cultural practices and market forces. Spore counts, however, are not reduced to zero.

In this scenario, APHIS reduces the size of the quarantine area, which reassures importers that the problem is contained and under control; APHIS and/or affected states establish realistic safe tolerance levels for spores, which encourages compliance with mandatory and recommended control practices; FAS and APHIS work to have importers modify their import requirements to accept a tolerance level of spores; scientific research tells us how to better control the problem; and fields with KB infections are shifted to other crops due to state regulations and market forces. Like boll weevil, we learn how to control it and live with it.

Trade problems would persist, however, with countries that continue to have a total ban on KB. Foreign countries may put a ban on wheat from the Southwest much like the ban China has on wheat from the Northwest, where the wheat disease TCK is common. TCK or dwarf bunt (Tilletia controversa Kuhn) is the same genus as Karnal bunt (Tilletia indica).

Except for China, TCK is not a serious trade problem with other important importing countries, even though TCK is more damaging to wheat than KB. USDA believes that the TCK requirement is an unnecessarily restrictive non-tariff barrier to trade and has negotiated with the Chinese for years over the issue. We feel APHIS is imposing a similar unnecessarily restrictive barrier against Arizona wheat.

SCENARIO #3: KB Is Eradicated to Absolute Zero - No Precedent

This scenario turns out, to be theoretical because we know of no instance of a wheat fungus being eradicated to absolute zero. Absolute eradication would be, by far, the best solution. It is, however, according to some experts, an impossible dream. Nevertheless, if KB were absolutely eradicated, the United States would continue to be threatened with re-infection from Mexico, therefore, the eradication program would need to be extended into Mexico to be effective.

SCIENCE PANEL MECHANISM DOES NOT WORK

Several factors have made this emergency worse than necessary and the Science Panel mechanism is a top factor. The Science Panel has great power because it directs, in large part, APHIS actions against KB and those actions have a large impact on U.S. wheat markets worldwide. The KB Science Panel is made up of three scientists from APHIS, three from ARS, and three from state agricultural departments.

The panel members appear to be laboratory scientists, some with a stunning lack of experience in real world pest control projects and real world agriculture. For example, one Science Panel member had to ask what "tillering" was.

Another very disturbing clue about the group dynamics of the Science Panel is how different the perceptions of the Science Panel are from those of other plant pathologists. According to Dr. Merritt Nelson, Head of the Department of Plant Pathology at the University of Arizona, most plant pathologists with extensive field experience believe that KB cannot be absolutely eradicated. He believes that if the American Phytopathological Society set up an ad hoc group regarding KB, that their recommendations would likely be very different than those of the Science Panel.

In "biologically" eradicating the boll weevil in Arizona, we believe that one of the reasons Arizona and APHIS have been so successful is because the academics, technocrats and industry have usually reached a general consensus on the best courses of action. The wide divergence of opinion between the academics and the technocrats regarding KB is worrisome and suggests deeper flaws in the Science Panel mechanism.

We fear that Science Panel recommendations may not represent the best scientific thought available but rather the inertia of the agencies involved. If there were a wider range of experiences on the panel, the panel should make better decisions. We recommend that future panels be less governmental, with less than half the members being government regulatory employees - or that the mechanism be eliminated altogether.

SOLUTIONS - Science, Education, Research and Perspective

No one knows if Karnal bunt will follow one of these scenarios - or if something entirely different will happen. The unexpected always happens. However, given the uncertainty and the importance of the issue, we should be prepared for any scenario. The key to moving past this problem and allaying fears in foreign markets is science.

Review Strategy Using Best Science Available

We do not have complete knowledge about KB and much research needs to be done. We do need, however, to resolve immediately whether or not KB can be eradicated to zero in the United States. APHIS tells us that they cannot take action in Arizona unless it is action to eradicate KB to zero. Arizona would like APHIS to help us with KB. Nevertheless, we feel that our battle plans should be determined by the biology of the pathogen not by agency policy. If there is reasonable evidence that KB cannot be absolutely eradicated to zero, we need to reevaluate our strategy and tactics.

Establish Immediate Interim Tolerance

This new problem will respond to an old solution, setting tolerances. We need to put the past behind us and have a fresh look at the scientific risks of using wheat with spore counts equivalent to parts per billion. APHIS should immediately establish a de minimis interim tolerance for KB spores for wheat going to food or feed use. As better scientific research becomes available, the tolerance should be adjusted. If spores are found scattered outside the quarantine area, then it becomes more important to have a previously established tolerance for spores.

Adjust Quarantine Boundaries

APHIS should immediately remove from quarantine all areas, and wheat from areas, where no spores have been found, such as Yuma County and the Casa Grande area in Arizona. This should help calm the fears of the world wheat markets by demonstrating that we are moving towards a solution. To date, approximately 95% of the fields tested show 110 evidence of any KB spores.

If other widely scattered areas in the United States are found to have incidental KB spores, such areas may need to be put under "observation," "investigation" or perhaps even "restriction," but "quarantine" may be counterproductive. Remember, drastic actions create drastic fears.

The results of the national KB survey should be released weekly, as is done in the Arizona program. APHIS, however, should act more deliberately to any new occurrences than they did to the Arizona occurrence.

Re-Open Foreign Markets Through Education

The most important step in making foreign restrictions more realistic is for USDA to review based on the best science available its own restrictions. Then FAS and APHIS should educate those countries that have KB import restrictions on our findings and encourage them to adopt similar standards.

Increase Research Dramatically

With better information we can make better decisions. This issue has affected millions of dollars of U.S. trade and the issue may be with us for years to come. Research focused on disease assessment would be a good investment.

In addition, the announcement of a large research effort on KB would likely allay some fears and increase confidence of U.S. wheat buyers. Such an announcement would also help prepare foreign buyers for the possibility of future changes in U.S. KB policy - if changes are warranted by the research results.

Perspective

Remember, despite all of the work and trade disruption, we have found only two (2) partially bunted kernels in Arizona this year. Perspective is always a key to success.