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Actual Evaluation of the Pesticide Use Report

I published this morning about putting the numbers being reported by the organic center about increased use of pesticides in herbicide tolerant crops into the proper perspective. In the introduction I mentioned:

I’m neither a statistician nor an agronomist, so I’m not qualified to confirm or refute the numbers they put forward. Hopefully we’ll see more detailed analysis on that end from someplace like biofortified or sustainablog.

And here, fresh from the biofortified forums, is a link to a report [pdf again I’m afraid] that goes into details with problems with the actually methodology used in The Organic Center’s report. (h/t to gntis for posting it)

From a quick skim (I’m too excited about the maize genome to be detail oriented):

  • The remaining acres grown with non-BT crops are grown that way for reasons (stricter pesticide regulation, more pest pressure, intentionally being grown as a low input crop, where the farmer accepts lower yields and puts a lot less money into fertilizer, seeds, and herbicides, possibly even acres in transition to organic certification (which requires three years)). They aren’t a random subset of all the acreage on which that crop is grown, and as a result using their herbicide numbers to extrapolate to what the total usage would be in the absence of biotech crops is wildly inaccurate.
  • There actually is a statistic, called the environmental impact quotient, (developed by Cornell!) which takes into account issues like differences in persistence, toxicity, and dispersal between different herbicides!
  • There are other more complete datasets on pesticide usage available (which paint a different picture from the one presented), which the author choose not to take advantage of, preferring to extrapolate from the incomplete data he selected.

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