Karnal Bunt: Experiences of a North-South Breeding Company, or:
Sixteen Weeks with a Political Disease Part 1 of 2
Dr. Dan Biggerstaff, General Manager, Western Plant Breeders

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I will discuss in detail certain events and activities, both inside and outside the quarantined area, that may not be familiar to many APS Symposium participants. Since the science, history, and politics of this minor disease are convoluted, my comments will move back and forth between various Symposium discussion topics.

Although much of the following is being discussed in some fashion by APS participants, some of what WPB has learned and endured has not yet been discussed on the APS Symposium. Our southern wheat and durum breeder, Kim Shantz, recently posted very important information (see General Comments, July 2) about his KB observations related to weather conditions in the Southwest.

To save space I will use common abbreviations where possible. In addition, I will use the following: KB = Karnal bunt; KBT = Karnal bunt teliospore(s); TIM = Tilletia indica Mitra, TCK = Tilletia controversa Kuhn, dwarf bunt.

1. Distinction Between KB Infection, Contaminated Seed, KB Teliospores

My first comments are about an important issue that is often handled very poorly by USDA/APHIS, the popular press, and even some APS symposium participants. I refer to the issue of making a clear distinction between a KB infection, infected seed, contaminated seed and KB teliospores. This issue is not one of mere semantics. It can be a critical distinction when discussing KB. As an example of this, the letter inviting participation in this symposium states: "In March 1996, scientists confirmed the presence of Karnal bunt in Arizona in certified durum wheat seed, the first known occurrence of this disease in the U.S. It has since been found in several counties in adjacent areas of Texas, New Mexico and California." (Bold added for emphasis.) The disease [KB] has not been found in those areas planted with "suspect" seed. However, I will guarantee you that almost everyone you poll in other states (or countries) is convinced there has been an "outbreak" of Karnal bunt in all three areas.

Most plant pathologists know that KB is not technically a seed-borne disease. A seed or a seed lot is not "infected" if it has one or a million KBT associated with it. It is certainly "contaminated" or more precisely "surface contaminated." APHIS press releases equate minimal surface contamination with "an infected seed lot." Their press releases imply that planting an "infected seed lot" results in a KB field infection. Planting seed with minimal "surface contamination" of KBT (1 to 3 KBT per 50 grams) poses essentially no risk of a field infection by the KB fungus during that crop year. I must add that the risk is not zero. One to three KBT per 50 grams of seed is the typical contamination in those seed lots used to plant the "suspect" fields in Texas, New Mexico, and the Imperial Valley of California. [And in other areas known to APHIS, but not quarantined. Yes, I will disclose later.] Even subsequent host crops are at very low risk of a KB infection if these few KBT are brought to the surface. (Assume an average planting rate of 135 lb./A [150 k/ha]; 3 spores/50 grams of seed yields about 9,000 spores per hectare or 3600 spores per acre).

Present and former KB researchers in India and at CIMMYT have indications that a detectable field infection, under favorable weather conditions, requires millions, if not billions, of KBT per square meter! Research is being undertaken to get a more conclusive answer to the question of how many KBT are required for a field infection. In addition, most wheat seed planted in the Southwest is treated with fungicides. While not 100% effective as KB fungistats, these treatments certainly reduce the number of KBT that will germinate.

Planting clean seed (free of KBT) into soil that contains KBT, on or near the surface from previous contamination, poses the greatest risk of a KB field infection in a given crop year. Previous contamination can be from: previously planted bunted or partially bunted kernels; combine deposited KBT when a field infection is present; wind-borne KBT; KBT contaminated insect or bird feces, or external KBT contamination (experiments have shown that white wing doves can carry millions of KBT in their feathers after a "dust bath" in KB infested fields); previously planted seed that was surface contaminated with KBT; or any soil (containing KBT) movement by people, dust storms, machinery, non-host crop debris, cars, Winnebagos, etc.

Detecting probable KBT in grain samples does not necessarily mean that a KB infection occurred in the field from which that grain originated. Detecting bunted or partially bunted kernels (from a KB infection) is definitive. One probable KBT in a sample of grain is the most common "positive" in 1996 pre-harvest samples, post-harvest samples and rail car samples. One teliospore can come from any number of sources ---- contaminated combine, road dust, contaminated conveyance, etc. I will return to the issue of "false positives" later.

Conversely, detecting no KBT in a pre-harvest or post-harvest grain sample does not mean that there are no KBT present in that field. (Read "Its the Weather, Stupid" in General Comments) Are KBT present in some fields that have tested negative? Of course they are! Are there fields outside the quarantine that contain KBT? The answer is obvious to any scientist.

Why make such a big issue of this? Because fields, facilities, and entire counties are being quarantined on the basis of perception and politics, not science. Because research nurseries are being destroyed, valuable germplasm and breeder's seed are being denied movement, and beautiful durum grain (and seed) is being dumped as feed on the same basis.

2. Infection Level

A second issue, related to the distinctions above, is the level of KB infection. What is a heavily infected lot? What is a high level of infection? I suggest the following conventions for describing the level of KB infection. Can we agree that grain having 3% bunted or partially bunted kernels is a heavily infected lot? Most research indicates that when 3% bunted or partially bunted kernels are present in a sample, the resultant flour may be discolored and have a fishy odor. Researchers in India report no significant quality reduction at infection levels up to 6% bunted or partially bunted kernels. Second, I propose that a grain sample having 1% bunted or partially bunted kernels should be described as having a high level of KB infection. I await expert opinions on these proposals.

Let's add some perspective to the issue of KB infection levels in this year's samples. I will use 10,000 seeds/lb. or 22,000 seeds/k as a working average for desert durum and wheat. In one 1995 sample we found 300 KBT per 50 gram sub-sample. In one kilogram of this sample we found two partially bunted kernels. That is an infection level of 0.009 %! It can be argued that a totally bunted kernel will be destroyed in the combining process and not be found in the grain. Even so, 1996 KB infection levels in the Southwest are some tiny fraction of 1% in fields that have KB infections. If the total wheat crop within the quarantined area is considered, the average infection level is very close to zero. An infection level this low can not be detected at an export elevator unless many samples are examined microscopically.

3. Serious Disease? Highly Infectious?

USDA, APHIS, and many newspaper articles describe Karnal bunt as a serious disease of wheat, durum, triticale, and rye. Karnal bunt is described in the Federal Register as "an injurious plant disease caused by a highly infectious plant pathogenic smut fungus, and can substantially reduce the yield and lower the quality of the wheat seed heads. As a result, Karnal bunt can have serious economic consequences for wheat growers." Poll hundreds of plant pathologists and see how many refer to KB as a serious disease. As several APS symposium participants have stated, APHIS purposely uses these terms to justify their actions and help secure additional funding for their bureaucracy. If Congress and the general public learn what a "wimp" of a disease KB really is, I think the USDA will be hard pressed to justify the 1983 or the 1996 quarantines.

Nearly every KB press release since March emphasized that KB causes yield loss and causes flour to be discolored and have a putrid or "fishy" odor. Once again, this misinformation is fostered by USDA/APHIS. In most cases the press releases do not bother to explain that the quality issue is only related to bunted kernels and usually not detected until more than 3% of the kernels are affected. Measurable yield loss is uncommon for this disease. The estimated yield loss in the affected areas of Northwest Mexico is slightly over 0.1% per year.

4. KB, Primarily a Disease of Proprietary Durum?

Review USDA/APHIS and state agriculture department press releases for the first two months of the present KB "crisis." Is it any wonder that most newspaper articles (even in farm publications) and TV news reported KB as a disease affecting durum. Yes, some of the articles may have included the stock phrase "of wheat, durum, and triticale" somewhere, but the emphasis was on durum.

Furthermore, these releases named the proprietary durum again and again. USDA/APHIS has done irreparable and unjustified harm to these named varieties. First they named 'Reva' and 'Durex' in AZ, then in NM and TX, then 'Kronos' and 'Ocotilla' in AZ and CA, then 'Durex' in MT and the lowest blow "thought to be 'Kronos' durum" in WA (See 7 below for details.) APHIS knew the material in WA was not 'Kronos,' and they named it anyway!

Some growers in MT, OR, WA, and ID who were interested in planting durum this spring because of its attractive price, decided not to risk a new, "serious" disease. All of our Northern Associate seed companies reported some version of the following paraphrase when they asked growers why they decided not to plant durum: "I would really like to, but I hear that it gets that 'disease' from Arizona." Sure this demonstrates ignorance about KB on the part of certain growers, but if you go back and read the newspaper articles, you will understand the origin of their concern. When the news of KB being found in durum at Moses Lake, WA, hit the press, we and our Associates in OR and WA received numerous phone calls from growers. Some who had already planted durum (seed produced in the North) wanted to know if they should immediately plow it out.

A plant pathologist with the Oregon Department of Agriculture called me and asked what variety of durum, found to have KB, was planted in the four acre field in WA. I asked him why he was inquiring. He indicated that the Director of his department felt it would be prudent to check all seed of that variety for KB, regardless of where the seed was produced. I responded by asking him what they would do if I told him it was Stephens (a soft white winter wheat grown on millions of acres in the PNW). He replied, "I don't understand. I thought it was 'Kronos'."

5. USDA/APHIS Actions Determine Quarantines

Prior to the US imposed quarantine on Mexico, very few wheat-importing countries had KB on their quarantine list. After the US imposed a KB quarantine on Mexico, the number jumped to 21. Since the USDA/APHIS quarantines were enacted in the Southwest, this number has more than doubled. Even Italy, a key importer of Desert Durum, added KB to its phytosanitary requirements after repeated requests for response by the US government. Bear in mind that Italy imports durum from Mexico without requiring two microscopic inspections for KB teliospores.

6. AZ Events Early in the Quarantine

When the press releases started to fly in March, we thought that our research nurseries south of Phoenix (Maricopa site) and southwest of Yuma were at very low risk for KB infections because of weather conditions and cropping practices. Even so, we were extremely concerned. WPB asked the AZ KB Task Force (a cooperative group set up by the Arizona Department of Agriculture and APHIS) to check our reserve seed samples. After numerous phone calls and several unsuccessful attempts to get official samples taken, we were able to submit samples on March 29. On April 5 we received our first results. Unfortunately some composite samples from our Maricopa site tested positive for KBT. No evidence of KB field infections has been found at our Yuma site.

By mid-April we had conclusive evidence that: 1) KB field infections occurred in red wheat at our 1992 Maricopa site; 2) KB field infections occurred at the 1993 Maricopa site in wheat and durum and in our neighbor's field (more prevalent than in 1992 or 1995); 3) no detectable KB field infections occurred at this site in 1994; and 4) WPB's Maricopa nursery site had KB field infections in 1995, but our neighbor's nursery on the other half of the same field did not. Our neighbor"s material (same checks as ours) headed 7 to 10 days later than ours because it was "irrigated up" two weeks later in the fall of 1994. Therefore, their material escaped infection. These nursery sites are on different fields each year and usually have 3 or 4 years of non-cereal crops prior to our use. An exception is the 2 year non-cereal rotation mentioned below.

When WPB tested positive for KB teliospores, the Task Force investigators started their WPB investigation. They were not interested in learning anything about where, when, or how the field infections occurred. Their only concern was to determine if any contaminated 1995 seed had been sent out of Arizona. Our southern breeder, Kim Shantz, completed a field history for our 1993 and 1995 sites. When he told an investigator that the 1995 site was planted to Yecora Rojo wheat in 1992 (non-host crops in 1993 and 1994) the response was, "So?" Then Kim asked, "Aren't you interested in previous host crops?" The response was "Should I be?"

Even when it was obvious that KBT were present in Arizona and California before 1992, and at widely separated sites, APHIS maintained their "contain and eradicate" position. We found it extremely difficult to cooperate with a Task Force that continued to preach the party line at every public meeting -- "contain and eradicate" -- when many of them privately admitted that there was no possible way of eradicating Karnal bunt.

7. Washington (State) Debacle

On March 19, WPB planted a spring nursery near Moses Lake, WA. Included in the last block of a four acre nursery was a 16 entry, 3 replication, durum yield trial (48 plots, 5' x 20' each, or 0.11 acres). Seed for this durum trial was grown in the Southwest in 1995 and was cleaned, treated with Vitavax RTU, and packaged at our Chandler, AZ, facility.

The first lab reports on our reserve samples (April 5) indicated no KBT associated with the durum entries planted in WA. However, lab results received by WPB on April 10, did implicate some of these durum lines. I notified the Task Force by fax on April 11 that we might have a problem outside the quarantine. We had an exact duplicate of this experiment (destined for a nursery in Idaho) that was submitted for testing. We received lab results after 5:30 p.m. on April 16.

On April 17, we received dozens of phone calls from all over the West asking about the KB found in WA. I was shocked to hear that a Knight-Ridder piece was on every grain trader's screen by mid-morning April 16. The piece had eight significant errors in it. When I confronted the Task Force, they assured me it did not come from them. After I faxed them copies of two releases quoting Beth Hulse and Larry Hawkins (APHIS Public Affairs, Wash. DC), their response was "Whoops, maybe it was us." I asked APHIS Public Affairs to print a correction. They did not.

The next day I flew from Bozeman to Moses Lake to attend a press conference orchestrated by Jim Jesernig, Director, Washington State Department of Agriculture (WSDA). I might add that I was not invited to this press conference. To keep Mr. Jesernig and 25-30 people from walking through our nursery, I requested an immediate Emergency Action Notice (EAN) [in effect, a field quarantine] from the Task Force in Phoenix. They assured me that an APHIS representative from Seattle or Spokane would serve me with an EAN before the 10:30 a.m. press conference. No one from APHIS even bothered to attend.

The press conference was pure political grandstanding. Mr. Jesernig, APHIS personnel, and others had discussed (for several days) the best solution to the "discovery of Karnal bunt in Washington." Their decision: 1) immediately plow the 4 acres of "infected" durum and the 160 acre registered wheat seed field surrounding it; 2) follow with a 5 year quarantine on the 160 acres. Isn't it amazing that none of them called WPB to get any facts. They did not know what was planted, the size of the experiment, the way it was planted, its location, the date it was planted or the present crop stage. Mr. Jesernig's only concern was public perception.

After two hours of discussions, our Associate seed company staff, our cooperator, and I were able to convince Mr. Jesernig that the best course of action was to fumigate the durum experiment and a buffer zone with methyl bromide and have no quarantine. The grower already planned two years of non-host crops and voluntarily agreed to five years. On April 26, 2.7 acres were fumigated at a rate of 500 lb. of methyl bromide per acre and tarped for a week.

Then on April 30, WSDA enacted an illegal quarantine on those areas of the US already under quarantine. The WSDA quarantine prohibited any host-crop seed or conveyances of the same from the APHIS quarantine areas, even if it qualified for an APHIS Phytosanitary Certificate and a Limited Permit (PPQ Form 530). This was purely political and accomplished nothing as far as "preventing Karnal bunt's introduction into Washington." It is technically illegal for any state to impose a quarantine that is more restrictive than a Federal quarantine, but it is certainly not without precedent. What this state quarantine accomplished was to cause other countries to question US phytosanitary assurances. To wit, "If states do not trust APHIS, should we?"

8. 1995 Breeder's Seed Quarantined in Montana

'Express' hard red wheat is the most successful fall-planted red wheat in the Sacramento Valley of CA. It is now becoming the most popular irrigated hard red spring wheat in many areas of MT and WA.

In 1995, at our Yuma location, WPB grew another increase of 'Express' line rows to produce Breeder's seed. Part of this increase was used in 1995. The balance was stored at Barkley Seed, Yuma, AZ. Unfortunately, this Breeder's seed of 'Express' had not been shipped North before the AZ KB quarantine was imposed.

It was very critical to move this seed to MT for production of Foundation seed in 1996. After numerous frustrating delays, we were able to get every bag (26) officially sampled for KBT analysis. On April 19 the results came back, all negative of course. APHIS issued a Phytosanitary Certificate indicating the entire lot "was officially sampled, and found to be negative for KB." We were also issued a Limited Permit, No. 452727, to ship this Breeder's seed to MT.

On April 24, the Task Force changed their mind and asked Barkley Seed to intercept this shipment and redirect it back to Yuma. It was already on the truck for local delivery, so we received it at Bozeman, MT, April 25.

Two APHIS personnel (one from Billings, MT [145 miles] and one from the Task Force in Phoenix [Thanks to the taxpayers, Delta sold a full fare ticket.]) arrived at our office to issue an EAN quarantining our 'Express' Breeder's seed. I asked for their justification. Had WPB or Barkley Seed not followed the APHIS protocol exactly? The Task Force representative agreed that we had done everything correctly, but there had been a misunderstanding. The Task Force apparently had no idea whatsoever that Breeder's seed is planted to produce Foundation seed. They needed to prepare another protocol for seed that might be planted to produce seed. The Task Force assured us that they were working on a solution to this problem. There is still no protocol to move any "seeds for increase" or commercial seed out of the quarantine. Our Breeder's seed of 'Express' is still wrapped with bright yellow US Government Quarantine tape.

In 1995, Barkley Seed produced in excess of 300,000 bushels of Certified wheat and durum seed in the Yuma area. About one half of this seed was sold outside AZ. The largest portion was sold in the Imperial Valley of CA, but large quantities were sold in the San Joaquin and Sacramento Valleys as well. Smaller amounts were delivered to the San Louis Valley of CO and the Gallatin Valley of MT. Bear in mind that remnant seed of all lots was tested for KBT after the quarantine was imposed and no KBT were found.

Why is it O.K. to have exported 9 million pounds of seed from Yuma, but it is not O.K. to export 2270 pounds of the same year's production? I defy APHIS or any APS Symposium participant to justify this as "good science."

9. California Nursery Destruction

The Pest Exclusion Branch, Division of Plant Industry, of the California Department of Food and Agriculture (CDFA) has a cooperative agreement with APHIS, like Arizona. CDFA had a very large, quarantine-experienced staff in place at the onset of the KB situation. Therefore, CDFA rather than a Task Force, manages KB operations in CA.

I will not expound on our experiences in CA to the extent that I did in the previous section on Washington. Suffice it to say the experiences in CA were similarly political and unpleasant.

WPB destroyed all five of our research nurseries in CA. We offered to destroy these nurseries and fumigate the soil like we did in WA. CDFA refused. They asked us to voluntarily fumigate but were going to impose a 5 year quarantine anyway, because "methyl bromide fumigation is only 98% effective."

On May 28, WPB received written notification that CDFA had accepted methyl bromide fumigation as an eradicative treatment for Karnal bunt. In the interim, one of our cooperators destroyed our nursery, according to existing protocol, and planted a crop of milo. All field operations were done in compliance with the existing protocol. Each time a piece of equipment left this field, it was washed with a 30% Clorox solution. WPB agreed to fumigate the soil later this summer, after the milo is harvested. On July 8, CDFA issued another EAN to this grower requiring him to immediately destroy the milo crop and fumigate the soil. The reason given: "Because it will look better." No scientific reason is being offered. One of the UC Davis Regional Trials sites (dryland) is fenced-off now and will be fumigated this fall. A seventy-five acre durum field in Fresno County, planted with seed that tested positive for KBT, was plowed but will not be fumigated. Apparently CDFA feels that it is O.K. to leave a KBT contaminated acreage, 15 times larger than WPB's, non-fumigated in another part of the San Joaquin Valley.

As a short aside, the maximum labeled rate for soil application of methyl bromide in CA is 400 lb. per acre. Most growers' applications use 300 lb. per acre. The APHIS protocol calls for 500 lb. per acre. Apparently CDFA convinced the pesticide regulatory group that it was necessary to bend the rules for this "serious" disease.

WPB lost all CA field trials this year, including performance data from nine UC Davis Regional Trials. In one nursery we were screening F4 and F5 head rows for septoria, leaf rust, and stripe rust resistance. This material was not replicated at any other location. No provisions were available to save even a single head from resistant rows.

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