Substantial equivalence - glyphosate tolerance

Asked February 28, 2014, 9:29 AM EST

I recently heard some remarkable information about substantial equivalence tests regarding glyphosate resistant crop varieties.

When a glyphosate resistant crop is grown to be tested for substantial equivalence tests, is it actually sprayed with the herbicide which it is designed to resist?

Washtenaw County Michigan

3 Responses

To my knowledge MSU does none of these types of tests. A call to the weed specialist got the response that 'That is a question for the registrant', meaning that the experimental procedures would be determined by the company registering the GMO and the US Food and Drug Administration, which would register the GMO for use. I had to look up 'Substantial equivalence' which in this case means that the GMO crop produces a product the is equivalent to the none GMO. Here is a link to a more in-depth discussion of GMOs and substantial equivalence in respect to GMOs. I thought your question was, is the crop treated with glyphosate before it is planted. During the seed propagation campaign when the plants are planted and harvested for elite seed and that seed is planted to produce more seed for commercial seed sales and production it would surprise me if the seed production fields were not treated with glyphosate herbicide for weed control. It would also surprise me if the crop products tested for the GMO glyphosate resistance trait would not be treated with glyphosate to enhance the expression of those genes and gene products for the substantial equivalence test against a non GMO crop and its products.

I thought the FDA was responsible for regulating the chemicals (like glyphosate) and that USDA regulates the crop itself. Does that seem right? In either case. Do you know who I could ask about how the crops are grown/treated during the substantial equivalence testing. If the registrant comes up with the experimental proceedure I'm sure someone at the regulating agency must have approved it.

Yes it is confusing. Generally pesticides such as glyphosate are regulated by the EPA. Something to be used as a food or a food additive is often regulated by FDA. Crops that would be used as animal feed, fiber, etc. are more likely to be regulated by the USDA. The GMO crop would go through APHIS if is was to be grown in the US. If you go down into the article I first linked to there are sections on how many countries regulate GMOs, and there is a section on the US and its regulator procedures. It is more detailed than my short description. Often a GMO crop will be regulated by several of these agencies depending on the end use. Since you are probably most concerned about human food I would think it would be all 3 agencies. You might start with the State FDA headquarters in Lansing and see if they will forward you to someone to answer your question. I suspect the people who can answer your questions work in Washington DC.