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[SANET-MG] soybean rust a new dread
Soybean rust is only new to the USA and Canada where it is called an asian
soybean rust that blew in from South America on the hurricanes.
The fungicide used to treat it, Headline®, is a member of a
fungicide family called strobilurins. There have been no cancer or birth
defect studies done on that fungicide as far as I can gather.
The fungus targets cytochrome B respiration.
There is a tangible fear among USDA people, not because the disease is
new so much as because they have gambled on RR soy. Most growers grow
strain - introduced a short time ago in genetic terms.
Essentially the whole crop is monomorphic (having little genetic
thus a new disease can sweep through and wipe out everything fast.
This is reminiscent of a near total disaster in the US corn crop in the
early 1970s. Most of the crop was based on a hybrid line with what was
called the texas (t) cytoplasm. A fungal corn blight appeared that
depended on the
texas cytoplasm and caused about a $10 billion crop loss that led into
a serious economic recession.
The use of RR soy poses a threat because it is monomorphic and the
lessons of that threat are clear!
3 DECEMBER 2004 VOL 306 SCIENCE www.sciencemag.org 1672-3
Plant Pathologists Gear Up for Battle With Dread Fungus
"No soybean can resist a rust that has finally arrived in the United
States, spurring a search for new varieties, predictive models, and
My comments continue as follows. USDA/APHIS knows about the problem of
monomorphic crops and disease but chose to go forward with corporations
to promote and spread highly monomorphic transgenic crops as is
" In a 1976 paper entitled "An Evaluation of Special Grant Research on
Southern Corn Leaf Blight," the USDA also acknowledged the genetic
uniformity in the nation's corn crop as one of the primary causes of the
1970 Corn Leaf Blight. "In the [1960s], it became clear that relatively
few corn breeding parents were being used to produce the bulk of
American hybrid corn varieties," said the report. "This narrowness of
germplasm set the stage for potential vulnerability to diseases, insects
and other stresses. In early 1970, environmental conditions in Southern
and Northcentral corn producing regions were favorable for easy disease
establishment and spread among vast plantings of highly uniform
varieties. The [Southern Corn Leaf Blight] epidemic became of national
and international significance."
Given weather conditions that enhance spread of the rust fungus the
widespread use of rr soy will require a large and expensive use of of
an apparently virtually untested chemical fungicide.
Organic growers have the inherent benefit of polymorphic varieties and
saved seeds. These are the features that USDA and the corporations seem
to be trying to wipe out!
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