Reader Comments on the paper
Karnal Bunt in Mexico
Guillermo Fuentes-Davila, Plant Pathologist
CIMMYT Wheat Program, Mexico
"One of the most important regulatory measures was the restriction on bread wheat planting in fields where disease incidence was over 2% infected kernels/kg.
However, this measure has not only caused important economic losses to farmers, but it does not help to minimize the disease..."
-From the paper.
THE FULL TEXT of Karnal Bunt in Mexico
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Gerald Holmes - 09:21pm Jul 5, 1996 EDT (#1 of 8)
Univ. Calif. Coop. Ext. Imperial Co.
Does the current U.S. crisis over KB parallel Mexico's crisis in the 1970-80s?
Is Mexico amused now that the shoe is on the other foot?
Do you think that it is
possible that many countries that have restrictions against KB
(e.g., China, Russia) might already have it, but have never
detected it due to low levels of disease and the lack of adequate
surveys?
Jack Riesselman - 03:42pm Jul 8, 1996 EDT (#2
of 8)
I believe that Mexico has
detailed records of where seed was shipped and also quanities
sent. This information would help many of us in the less
favorable environments convince necessary individuals that
certain environmental parameters need to be met before the
disease occurs.
Guillermo Fuentes-Davila - 07:02pm Jul 8, 1996 EDT (#3
of 8)
answer to Jack Riesselman: the following information was taken from the study "economic losses from karnal bunt of wheat in Mexico" by Brennan, J. P., Warham, E. J., Hernandez, J., Byerlee, D., and Coronel, F. 1990. CIMMYT Economic Working Paper 90/02. The study refers specifically to the affected areas of Sonora, Sinaloa and South Baja California.
NOTE: THE FIRST NUMBER IS THE YEAR, THE SECOND IS TONS OF SEED FROM
SONORA, AND THE THIRD IS TONS FROM TOTAL (SEE FOOTNOTE)
Table 2.11. Mexico's wheat seed exports
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year Sonora Total Destination
metric tons
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1964 20 0 USA
1965 40,000 0 India, Guatemala
1966 0 1 --
1967 21,000 66,499 Turkey
1968 1,650 2,607 USA
1969 4,600 5,514 USA, Syria, Libya
1970 11,646 11,814 USA, Algeria, Argentina
1971 59,371 61,189 Iraq
1972 15,493 15,789 Algeria
1973 9,950 10,668 China, Greece
1974 7,495 18,971 China
1975 42,480 30,253 USA, Brazil
1976 10,372 12,252 Spain, Brazil, Greece, Ecuador
1977 14,811 22,797 Libya, Algeria
1978 16,034 13,929 Pakistan, Brazil, Portugal
1979 12,746 14,352 Bangladesh, Libya, Greece
1980 20,161 23,065 Spain, Greece, Bangladesh, USA
1981 4,287 5,000 Greece, Spain
1982 700 638 Greece
1983 71 87 --
1984 0 202 --
1987 2,321 3,500 Bangladesh
1988 2,000 2,000 Tunisia
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SOURCE: PRONASE (National Seed Producer) for Sonora, and SARH (Department of Agriculture and Water Resources) for total. Note that the two series are not directly comparable for all years.
You have to consider also
the universities from the USA and Canada that had wheat,
triticale and barley breeding activities in the Yaqui valley for
quite some time.
Gerald Holmes - 03:11am Jul 9, 1996 EDT (#4 of 8)
Univ. Calif. Coop. Ext. Imperial Co.
For Guillermo: What precipitated the restrictions against KB? If Mexico knew of the disease by 1970, what happened in the mid-1980's that everyone become concerned about KB? Was it the Indian experience of increased losses with new susceptible varieties? Also I'd like comments on my first message if you're so inclined. Thanks.
As long as we have a
perspective from Mexico, we should have one from India. How this
thing came to be what it is today is fascinating. I'd love to
hear India's story.
Byrd Curtis - 10:01am
Jul 9, 1996 EDT (#5 of 8)
In response to Gerald Holmes question about the lack of attention to KB during the period, 1970-1983, many US scientists, including myself, (most of that time as a wheat scientist working in Colorado) were aware that KB was in Mexico. I can only assume that APHIS was also aware of the situation. Why the 1983 growing season was chosen by APHIS to become excited about KB is probably a result of two reasons: 1) One of the heaviest KB infections occurred in the Mexican state of Sonora that year and 2) bad as I hate to say it, many of us thought that APHIS succumbed to wishes of certain aspects of the US Wheat Trade to find a way to prevent Mexico wheat grain and seed being imported into the US. Considerable wheat grain was being traded between Mexico and the US at that time and much seed of improved Mexico varieties was being sold to the US. If indeed, the second reason was intentional, it really worked! Not only did it halt grain and seed shipments, it virtually stopped exchanges of breeding germplasm between the US and Mexico. Prior to 1983, several US public and private institutions sent breeding materials to Mexico with the intent of obtaining an extra generation to speed up development of new varieties for the US. This was a wonderfully efficient system and greatly enhanced the development of improved wheat germplasm for both countries, not to mention the wheat germplasm improvements realized by many developing countries (from seed received from Mexico).
It is time that plant
scientists take action toward regulatory systems with the purpose
of assuring that the regulations embody science (and good sense)
and rid the system of political interference that only satisfy
the greedy.
Jack Riesselman - 03:48pm Jul 9, 1996 EDT (#6 of 8)
For Guillermo and Byrd:
Guillermo, thanks for the data. From old seed traders I've been
informed that Mexican seen was used in PNW locations etc. Any
knowledge of where in the U.S. Mexican seed was sent? Byrd, also
appreciate your comments and I agree completely. A question for
Bryd, From a reliable source who once worked for the USDA I was
informed that in the late 60's or early 70's KB was reported from
Texas and a USDA team was sent to manage that occurrence. Any
information on that? Thanks!
Byrd Curtis - 07:27pm Jul 9, 1996 EDT (#7 of 8)
Thanks Jack for your comments. I had not heard about KB being in Texas in the early 70's but I have no doubt about that possibility considering the thousands of tons of Mexico wheat seed being introduced into the US in the late 60s and early 70s. It is simply amazing, from a scientific viewpoint, that if KB is such a potential hazard (as viewed by APHIS) that it was not found in the US earlier than March 8, 1996.
Why is it that APHIS
representatives are not responding to papers and comments of this
symposium? Maybe we have another "gate" that could be
called "APHIS-KBgate" on our hands. In any case, the
public and Congress should be appraised of this situation. If
anyone out there has any ideas how best to do this, let us hear
from you.
Guillermo Fuentes-Davila - 07:33pm Jul 9, 1996 EDT (#8 of 8)
to Gerald Holmes: I am sorry I am not the best individual to answer your questions. At the time of the so-called kb crisis in Mexico, I just had initiated my graduate studies at WSU in Pullman. I think Byrd gave a pretty good idea of what happened at that time (thanks Byrd!). The question about Mexico being amused that kb is present in the USA, I would recommend to ask Dr. J. Trujillo, director general of the Mexican plant health inspection service. The only comment that I can make about this aspect, is that several scientists (including some from the USA and myself) believed that eventually kb would appear in arizona or california (at what level?) because of the wind-blown teliospores from northwest Mexico, and that economic support should be provided to continue the research. Regarding the question about the possibility of kb in other countries, I can not give any answer because it would be just speculation without scientific data. It is important to consider the following factors for kb development: quantities of viable teliospores on the soil surface; environmental factors conducive for teliospore germination; environmental factors conducive for sporidial release, multiplication, mating, penetration-infection, and the host.
Answer for Jack Riesselman: I do not know the areas in the USA where the mexican seed went.
I will check in tomorrow
and then out for about 10 days.
© Copyright 1996 by the American Phytopathological Society