The long-term ecological and environmental effects of herbicide-tolerant crops have not been considered

We are writing to express our concern over the recent recommendation for approval for the environmental release of genetically modified mustard (“DMH-11 hybrid”) in India. The recommendation was made by the Genetic Engineering Assessment Committee (GEAC). Our concern is based on several aspects of the release proposal. First, the potentially adverse long-term ecological and economic consequences of the release of DMH-11 have not been sufficiently considered. Second, details of mandatory testing to ensure food and environmental safety, which is a prerequisite for release into the environment, have not been made public. Finally, a detailed long-term assessment of the potential social and economic benefits of using DMH-11, vis-à-vis its potential harms, remains to be done. Without minimizing the importance of the last two aspects, this note limits itself to underlining the first aspect.

A central feature of DMH-11 is that it carries a gene for herbicide resistance (also called herbicide tolerance or HT). This fact has not received the attention it deserves. The deployment of herbicide-resistant or TH crops has been accompanied by deleterious results in several places, including the United States, Australia and Canada (so-called developed countries) as well as in Argentina (a developing country). The best-established harmful consequence has been the spread of herbicide-resistant weeds over large areas of agricultural land, which can be catastrophic for normal cultivation.

The developers of DMH-11 stated in their 2016 Food and Environmental Safety Assessment submission that “Although the genetically modified mustard hybrid DMH-11 contains the bar gene conferring resistance to the herbicide Basta (phosphinothricin )…Basta herbicide should only be used by seed grower for hybrid seed production…(and) farmers are not required to spray Basta in hybrid GE DMH-11 for weed control The GEAC, in its October 18 recommendation for the release of DMH-11 into the environment, accepted this position and also laid down certain conditions for release into the environment. The first is that “the use of any herbicide formulation is recommended only under controlled and specified conditions exclusively for the production of hybrid seed…”. Another is “The use of any herbicide formulation is only permitted for r cultivation in the farmer’s field under any circumstances and such use would require the necessary authorization in accordance with the CIB&RC (Central Insecticides Board and Registration Committee) procedures and protocols for the safety evaluation of insecticides/herbicides ). ).” In other words, the GEAC assumes that farmers will use DMH-11 without adding herbicide even though they know it carries a herbicide resistance gene. It ignores the known fact that there have been numerous recent reports in the Indian media of the illegal use of unapproved herbicide resistant crops, which have come to the attention of the government. It is highly likely that DMH-11 will also be grown with a herbicide if it aids in weed control, as is expected to be the case. Further, the GEAC considered the possible use of herbicides with DMH-11 simply as a matter of herbicide use and referred its approval to the CIB&RC, which records herbicide use on a crop basis. However, in several respects, TH technology is qualitatively different from the conventional use of herbicides. They include the levels of herbicides used, which are much higher than in conventional use; its effect on the crop which is designed to be resistant to the herbicide and thus tolerate much higher levels of herbicide; and its agro-ecological impact, including on agricultural biodiversity and insect populations. The magnitude of the problems with using herbicides with a herbicide resistant crop puts it squarely within the scope of GMO regulations (i.e. GEAC). It is not enough for the GEAC to simply refer it for chemical registration since the CIB&RC is not the competent body to recommend the approval of GM crops.

Thus, notwithstanding the developers’ statement and its implied acceptance by the GEAC, the DMH-11 meets the definition of a TH culture. The answers to two questions show this. Is DMH-11 herbicide tolerant? Yes. Is it a culture? Yes. The developer’s intent as to how it is intended to be used does not determine how it is actually likely to be used, particularly if such use appears to confer obvious benefits.

We reiterate that HT technology involves the use of a herbicide in much higher amounts than conventional herbicide treatments, high enough to kill all the weeds in the field, leaving only the modified crop to grow. Thus, it replaces all other weed control measures. It may be effective for a few years. But basic evolutionary considerations, as well as experience from other countries, show that it imposes strong selective pressure for resistant weeds to emerge. They invariably do this over time and spread rapidly. Once this happens, even higher amounts of herbicide must be used; the cycle continues gradually. HT offers short-term benefits at the expense of long-term durability.

We are aware and appreciate that a great deal of time, effort and resources have gone into the development and testing of DMH-11 Mustard. It is also possible that safety issues related to herbicide tolerance were not fully apparent at the time of its design and development. However, the existing investment should not prevent us from seriously analyzing the risk posed by HT technology. In our view, the risk outweighs any benefit that may arise from its deployment.

Borges is Professor at the Center for Ecological Science, Indian Institute of Science, Bangalore; Gaur is Professor Emeritus, Center for Mathematical Modeling and Computer Simulation, Bangalore; Nanjundiah works at the Human Genetics Center in Bangalore; and Siddiqi, Center for Cellular and Molecular Biology, Hyderabad. The opinions expressed by all authors are personal

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