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Scientist says biotech companies encouraging GMO-herbicide treadmill
Ken Roseboro
Organic & Non-GMO Report, April 4 2012
http://www.non-gmoreport.com/articles/april2012/scientist-biotech-gmo-herbicide.php

The dramatic rise of weeds resistant to glyphosate, the main ingredient in
Monsanto's Roundup herbicide, is leading biotechnology companies to develop more
genetically modified crops that are tolerant to older, more toxic herbicides
such as 2,4-D and Dicamba.

In a paper published recently in BioScience, David Mortensen, professor of weed
ecology at Penn State, and fellow researchers criticized this "single tactic"
approach of herbicide-tolerant GM crops to control weeds. The paper says the
approach will dramatically increase herbicide use and threaten environmental
quality, create even more herbicide resistant "superweeds," and encourage
continued neglect of public research and extension investment in integrated weed
management approaches in favor of chemical company profit-driven GMO approaches.

In 2010, Mortensen told a US House Oversight Committee that the government
should restrict the use of herbicide-tolerant GM crops and impose a tax on GM
seeds to fund research and educational programs for farmers.

Ken Roseboro, editor of The Organic & Non-GMO Report, recently interviewed
Mortensen.


What were the key findings of your paper published in BioScience?

Dave Mortensen: There are three parts to the paper. In the first part we
outlined the problems with genetically modified herbicide-tolerant crops. The
over-reliance on glyphosate herbicide, coupled with vast acreage of
glyphosate-tolerant GM crops, including most recently Roundup Ready alfalfa and
sugar beets, has created intense selection pressure for the evolution of
glyphosate resistant weeds.

In the second part of the paper we discuss how the biotechnology companies are
reacting to this weed resistance problem by introducing more genes into crops
that will facilitate more herbicides to control weeds. The companies are using
GM methods to ramp up herbicide use. This industry-led solution is causing a
transgene-herbicide treadmill that will result in a doubling or tripling of
herbicide use in corn, soybeans, and cotton.

The companies are saying that the way to manage resistant weeds is to use
multiple herbicides and more GM crops. We know from past experience that a
silver bullet approach will not solve complicated weed problems.

We do understand why farmers would use the glyphosate and glyphosate-resistant
crop package. It is simple and relatively cheap, but we have to think about the
long-term consequences.

In the last part of the paper we discuss practical approaches for integrated
weed management. These approaches, such as cover cropping, go in a different
direction than what biotech companies want to go.


How many weed species are now resistant to glyphosate?

DM: Twenty-one, and 75 percent of those have been documented since 2005, despite
company-sponsored research stating that the resistance would not occur.


How many millions of agricultural acres are affected by glyphosate-resistant
weeds?

DM: I believe there are 15 million acres of land affected with glyphosate
resistant weeds. There are a number of projections by biotech companies that the
number of affected acres could hit 20 or 30 million in the next few years.


You talk about a transgene-facilitated herbicide treadmill. Please tell me more
about this.

DM: The biotechnology companies' reaction to the weed resistance problem is to
develop more herbicide-tolerant GM crops that will encourage more herbicide use
to control weeds. The companies are creating a genetic modification treadmill
similar to the pesticide treadmill experienced in the mid-20th century, when
companies produced increasingly more toxic substances to manage pests resistant
to pesticides. This continual insertion of more genes into crops is not a
sustainable solution to herbicide resistance.

Another aspect that is disturbing is that the original justification for
developing the herbicide-tolerant GM crops was that we would move away from
older, less environmentally benign herbicides. Specifically, several companies
are actively developing crops that can resist glyphosate, 2,4-D and Dicamba
herbicides. Such genetic manipulation makes it possible to use herbicides on
these crops that previously would have killed or injured them. What is more
troubling is that 2,4-D and Dicamba are older and less environmentally friendly.

Will weeds becoming resistant to these other herbicides?

DM: Yes, weeds will eventually evolve combined resistance to Dicamba, 2,4-D and
glyphosate. Globally, there are already many examples of weeds simultaneously
resistant to two or more herbicides.


What are some other problems with 2,4-D and Dicamba?

DM: Increased use of 2,4-D and Dicamba applied over the growing corn and soybean
means much more of these herbicides will be applied at a time of year when many
sensitive crops like tomato and grapes are most vulnerable to injury. Such
injury results when these herbicides move from the targeted field during or
following an application.

Overuse of herbicides may increase chances that farmers will use the herbicide
during inappropriate weather conditions, leading to herbicides drifting from the
targeted area and killing or harming other non-target plants and crops.

I recently saw a database on pesticide spray drift complaints. These happen when
a farmer applies herbicides and they blow into adjacent fields or gardens and
damage that crop or garden. In the most recent years, the most frequent
complaints involved 2,4-D, Dicamba, and glyphosate. What's worrying is that
farmers aren't even using much 2,4-D and Dicamba now, but they will be with GM
crops being ramped up for marketing in the next few years.

The harm to non-target plants (from pesticide drift) is likely to amplify
greatly with the use of these older compounds.


You recommend integrated weed management as a solution to the weed resistance
problem. What are the practices involved in this?

DM: Planting cover crops, rotating crops, and using mechanical weed control
methods, as well as targeted, judicious use of herbicides.

Cover crops such as winter rye, hairy vetch, crimson or red clover can be
planted in early fall following annual cash crops, or seeded in early spring.
These crops add a smothering effect and keep weed seeds from emerging.

In the Northeast, there are now incentives to encourage farmers to adopt cover
crops to enhance water quality in the Chesapeake Bay. I recently heard a talk by
John Lundgren (an entomologist with US Department of Agriculture's Agricultural
Research Service) who said that cover cropping can significantly reduce pest
pressure and insecticide use.

Unfortunately we have an agricultural industry that doesn't want to encourage
cover cropping because it goes in the opposite direction of where they want to
go with GM crops and herbicides.

© Copyright The Organic & Non-GMO Report, April 2012
The Genetic Engineering News is produced by Thomas Wittman and EcoFarm, and supported by a generous donation from the Newman's Own Foundation.  Please pass this vital information on.  If you would like to get on this list go to www.eco-farm.org and select Newsletters.

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