Do genetically engineered crops really increase herbicide use?

Another interesting article about GMOs has been making the rounds today. This one was written by Dr. Charles Benbrook, Chief Science Consultant for The Organic Center. This publication is an updated version of a report that The Organic Center published in 2009. The new version has been published in “Environmental Sciences Europe” and can be downloaded here for free (hooray for open access!). The title of the article is “Impacts of genetically engineered crops on pesticide use in the U.S. — the first sixteen years”. The following excerpt from the abstract provides a pretty good summary of Dr. Benbrook’s analysis:

A model was developed to quantify by crop and year the impacts of six major transgenic pest-management traits on pesticide use in the U.S. over the 16-year period, 1996–2011: herbicide-resistant corn, soybeans, and cotton; Bacillus thuringiensis (Bt) corn targeting the European corn borer; Bt corn for corn rootworms; and Bt cotton for Lepidopteron insects.

Herbicide-resistant crop technology has led to a 239 million kilogram (527 million pound) increase in herbicide use in the United States between 1996 and 2011, while Bt crops have reduced insecticide applications by 56 million kilograms (123 million pounds). Overall, pesticide use increased by an estimated 183 million kgs (404 million pounds), or about 7%.

Contrary to often-repeated claims that today’s genetically-engineered crops have, and are reducing pesticide use, the spread of glyphosate-resistant weeds in herbicide-resistant weed management systems has brought about substantial increases in the number and volume of herbicides applied.

Reuters recently reported on the article (pretty uncritically you might notice). And that article has been re-printed (also uncritically) in several other online news outlets. I’m not going to address the point that lumping all pesticides together while ignoring toxicity doesn’t make much sense… others I’m sure will address that. I reviewed Dr. Benbrook’s previous report (after 13 years) a couple years ago, so I was already somewhat familiar with the methodology he used. Which is good, because the “Methods” section of this most recent paper on estimating herbicide use is pretty sparse (and confusing). Basically, Dr. Benbrook uses USDA-NASS data to estimate herbicide use on both conventional and herbicide resistant crop acres. This is no easy task for several reasons. First, USDA (presumably due to budget cuts) does not collect pesticide use data very often anymore. They had completely stopped for a while, and I believe are now starting again, but in a limited capacity (not all crops in all years). I agree with Dr. Benbrook that this lack of independent pesticide use data is very frustrating.


UPDATE: October 3, 2012. I have recently been reminded that USDA-NASS is not the only source of pesticide use data. There are companies that collect this information and will make it available. However, these companies also charge for use of this data. So while the data have similar (or possibly better) accuracy compared to government statistics, they will cost money to obtain.


Dr. Benbrook acknowledges a second hurdle in estimating herbicide use on conventional and herbicide resistant acres:

NASS surveys do not report pesticide use on GE and conventional crop hectares separately.

Dr. Benbrook devised a way to get around that, but I honestly still can’t quite figure out how he did that… Here’s his description if you want to try and follow it:

The volume of herbicides applied to HR hectares can be approximated by adding NASS reported glyphosate use per crop year to an estimate of the volume of herbicides other than glyphosate (hereafter, “other herbicides”) applied on HR hectares. The volume of “other herbicides” applied on HR hectares is estimated based on the average number of nonglyphosate herbicides applied per hectare, coupled with the average rate per application of non-glyphosate herbicides. In addition, the rate of “other herbicides” on HR hectares is adjusted to reflect changes from year to year in overall herbicide use and glyphosate application rates. For example in recent years, “other herbicides” have been applied to around one-half of HR soybean hectares at an average rate of ~0.34 kgs/ha (~0.3 pounds/acre), resulting in an average ~0.17 kgs/ha (~0.15 pounds/acre) of “other herbicide” applications on all HR hectares (0.5 x 0.34).

I decided to take a look at the data that Dr. Benbrook used to come to his conclusions. To his credit, he has provided the data he used as a supplemental file, linked at the end of the manuscript. The MS Excel file can be downloaded from here. The first worksheet in that Excel file is titled “Sup Tab 1 Herb Rates” and contains herbicide applications per acre for the period 1995 through 2011. It appears to be a mostly complete data set, but some very important information is in the footnotes:

1)  The average rate per treated acre for total herbicides and all glyphosates applied to corn, are supplied by NASS (italicized), with the exception for the years 2004, 2006-2009 which are interpolated. 2011 is forecasted with a 2.5% increase for glyphoste and a 2% increase for total herbicides.

2)  The average rate per treated acre for total herbicides and all glyphosates applied to soybeans are supplied by NASS (italicized), with the exception of 2003 which is interpolated. Total herbicides applied for the years 2004 – 2011 are forcasted at a rate of 3% increase per year.  Glyphosate applied for 2007-2009 are forecasted at a 3% rate increase per year, then 2% and 4.4% for 2010 and 2011 respectively.

3)  The average rate per treated acre for total herbicides and all glyphosates applied to cotton are supplied by NASS (italicized), with the exception of the years 2002, 2004, 2006 and 2009 which are interpolated. Total herbicides applied for 2011 is forcasted at an increased rate of 2.0%.  Glyphosate applied for 2011 is forecasted to increase by 1%.

So basically, Dr. Benbrook is saying he did not have NASS data for 2004, 2006, 2007, 2008, 2009, or 2011 for corn, and instead “interpolated” or “forecasted” values for those years. For soybean, he forecasted all data after 2006 (since no NASS data were available). Cotton had the most complete data set, only missing 2002, 2004, 2006, 2009, and 2011. I’m not opposed to interpolating or forecasting data when observed data aren’t available. That’s life. But I think when data are estimated instead of observed, it is fair to question how those estimates were derived. Let’s first take a look at the cotton data, since it is the most complete data set from NASS. Below I’ve plotted the actual NASS data in black, and a linear regression line through those data. If I were going to interpolate or forecast, this would be how I would do it. I would determine if there is a trend, and use the trendline to estimate points where data is not available. This smooths out any year-to-year variability (due to wet spring weather, drought, or other factors that influence weed management). The P-value for the regression line is in the plot for any stats folks who are interested.

 

Although Dr. Benbrook’s estimates (in red triangles) don’t fall on my regression line, I think his estimates seem reasonable for total herbicide use in cotton. My forecasted estimate for 2011 herbicide use on cotton would be pretty similar to what Dr. Benbrook came up with using different methods. So there does appear to be an increase in the total amount of herbicide applied to cotton acres in the US between 1995 and 2011.

For corn, we came up with a little bit bigger differences, though. If I plot the NASS data and run a regression for total herbicide use in corn, I get a downward trend (0.039 lbs ai/treated acre per year to be exact). Dr. Benbrook, on the other hand, assumes a mostly linear increase between 2005 and 2010, and extends that increase through 2011.

So I would make the assumption that 2010 herbicide use was slightly above the predicted value (again, due to year-to-year variability) of the regression line, but we’re still observing an overall downward trend in herbicide use per acre over the period. Because that is the conclusion the observed data will support. I suppose I wouldn’t disagree too strongly with Dr. Benbrook’s estaimates here, although I would argue that using my downward trend, or even no trend between 2000 and 2011 would probably be more justifiable than the steady increase he predicts.

But now take a look at the soybean data. This is the most incomplete data set from NASS, and Dr. Benbrook had to forecast ALL pesticide use data between 2007 and 2011. It has been a while since I’ve been in time-series statistics class, but I’m pretty sure forecasting 5 years of data based on only 11 years of observed data is frowned upon.

 

Dr. Benbrook states in his article (I’d provide a page number, but there are none on the PDF):

In terms of overall herbicide use per hectare based on NASS data, substantial increases have occurred from 1996 through 2011.

and:

Compared to herbicide use rates per hectare on non-HR hectares, HR crops increased herbicide use in the U.S. by an estimated 239 million kgs (527 million pounds) in the 1996–2011 period, with HR soybeans accounting for 70% of the total increase across the three HR crops.

First, based on actual NASS data, herbicide use between 1995 and 2006 showed no statistical trend either upward or downward for soybean herbicide use (the slope of the non-significant trend line is slightly positive).  But for some reason, Dr. Benbrook forecasts an unprecedented increase in total herbicide use in soybean. He assumes that the increased use in 2006 is the new normal, instead of more variation around mean. There was very little in the previous 10 years of actual soybean herbicide use data (1995 through 2006) to support Dr. Benbrook’s predicted increase in herbicide use. Dr. Benbrook then states that his “modeled” data on soybean herbicide use actually accounts for a whopping 70% of the total increase across the three crops. Let’s assume that Dr. Benbrook is is correct about cotton herbicide use (he’s probably pretty close). Let’s also give him the benefit of the doubt about corn use, even though he turned a downward trend into an increasing trend. Using his own estimate, 70% of his estimated increase in herbicide use is based on this extrapolated soybean data, that are not well supported by actual USDA data. If anyone has a link to some actual herbicide use data for soybean for the period 2007 to 2011, I’d be more than happy to update the analysis to include those numbers. Until then, I have some pretty strong questions about the “model” Dr. Benbrook used to estimate herbicide usage on these crops.

Benbrook, C.M. 2012. Impacts of genetically engineered crops on pesticide use in the U.S. — the first sixteen years. Environmental Sciences Europe. 24:24. doi:10.1186/2190-4715-24-24.

 

Comments

  1. Andrew –

    Don’t know how you missed it — NASS surveyed soybean pesticide use in 2006, so values for 2007-2011 are projected, not 2003-2011 as you state. Look at the trend in total herbicide use and glyphosate use on soybeans in Suppl Table 1. Use went up about 0.2 pounds/acre just between 2005-2006; I assumed only another ~0.2 pound/acre increase between 2006 and 2011, despite spread of multiple resistant weeds. I’ll bet you $10 that when NASS reports total soybean herbicide use for 2012 in soybeans next July the increase will be greater than my projected 0.2 pound/acre. It is very clear in the NASS data, notwithstanding my model, that herbicide use has gone up sharply in soybeans and cotton, with glyphosate accounting for the rise. The trend in corn is less obvious and extreme, but still herbicide use on corn is heading higher.

    1. Hi Chuck,
      Thanks for stopping by to comment. I’m basing my figures on your footnotes to Supplemental table 2. Your second footnote states: “Total herbicides applied for the years 2004 – 2011 are forcasted at a rate of 3% increase per year.” I interpreted that to mean you forecasted all of those years. So to clarify, you’re saying that 2003 is missing, and 2004-2006 are observed data? I have updated the post to reflect that.
      I agree with you on cotton. I think the data are pretty clear there. I’m less in agreement in corn, and even less so on soybean. I would never bet $$ on the Feds, but I’ll buy you a beer if your projection is closer to the 2012 USDA soybean estimate than mine. :-)
      AK

    2. And yes, herbicide use did go up in soybean about 0.2 lbs/A between 2005 to 2006. But there are 0.2 lbs/A jumps up and down in all of the data sets. That isn’t always the beginning of a trend of consistent increases every year. It is very likely just a fluctuation for that year, and will go back down the following year.

  2. Are there increases in harvested amounts for these crops? I was just wondering if you get more production associated with this usage as well.

    1. That’s a very interesting question, and it illustrates another shortcoming of Dr. Benbrook’s approach. Simply counting pesticide “pounds on the ground” has its place in the grand scheme of things, but without additional information, it doesn’t really mean much. As you mention if you spray more pesticide, but increase yield significantly, then perhaps that is an acceptable trade-off. Especially if the pesticide used has a reduced environmental impact. But those are two things that this study does not quantify: the effect of pesticide use on crop yield, and the toxicity of the pesticides used.

      So to answer your question: sometimes. Another problem with bulking ALL crops and biotech traits together, is some traits in certain crops result in increased yield. Some do not. Some require more pesticide, but in return produce greater yield. Some require similar amount of pesticides but increase yield. Others don’t increase yield, but reduce pesticide usage. And some require fewer pesticides AND increase yield. But the press releases (and Dr. Benbrook’s abstract) simply lump all of this together into one giant calculation. Which again, has its place, but is not really very meaningful.

      1. Thanks, yeah, I see. As I kept musing on this, I realized how hard it would be to get data because you’d have to have similar fields nearby without weed controls and compare for really good assessment. And it might not be increase in yield so much as not losing to weed competition.

        I had another thought later too. I remember when GMO beets were coming along that reductions in human labor for weed-pulling was going to be substantial. I know some people in the organic realm think this back-breaking work is a good job opportunity, but I think fewer people having to do that really hard work is probably a better thing.

  3. When comparing herbicide use on HR and conventional farm areas always remember that the main reason farmers don’t grow HR varieties in ‘conventional’ areas these days is because they don’t have a weed problem in the first place.

    If an HR farmer decided to go back to conventional ways in a ‘high weed pressure’ area he would be using higher rates of herbicide than those recorded as the baseline control values in this study.

    Also as you say, lumping all pesticides together while ignoring toxicity is ludicrous. In all pesticide types (herbicide, fungicides, insecticides) the chemistry now is far less toxic to humans and the environment than even 10 years ago. Many of the worst offenders have been outlawed (especially in the EU where I am) and that includes many of the traditional ‘Organic’ pesticides.

    James

    1. Hi James,
      That’s an interesting observation, and one that I can attest to with a biotech crop Dr. Benbrook did not analyze: Roundup Ready sugarbeet. Within 3 years of commercialization, over 90% of the US sugarbeet acreage was planted to RR sugarebeet varieties. The only fields that continued to be planted to conventional varieties were those that did not have major weed problems to begin with. This would certainly confound the analysis, because fields with low weed pressure will receive reduced pesticide application regardless of whether they are Roundup Ready or not. I’m sure this is also the case in other crops (particularly corn). The Roundup Ready seed is going to be planted in the weediest fields, and will therefore require more herbicide, regardless of which herbicide you use.

  4. Andrew, an interesting critique. I was aware that Benbrook was having to forecast use because the data wasn’t available from NASS and he wasn’t taking advantage of the other sources. But frankly his approach has always been suspect. The data is not disaggregated in NASS into GM users and non-GM users, so Benbrook just guesses. He claims to have a special data set which NASS disaggregated for him, but as far as I am aware no-one else has seen that data.

    Benbrook’s approach has led to some interesting errors in his previous reports, which I documented, including one where he had more herbicide being used in GM soybeans in the US than was used on all the soybeans growing (although that one had incorrect forecasting as well as an incorrect way of distributing the herbicide).

    Benbrook would have been better advised to have purchased the disaggregated data and used that, like Brookes and Barfoot did. But then perhaps he might have come up with the same result that they did.

    Chris

  5. I read with great interest your article. You and the comments mentionned the difficulties to assess the trends in the herbicide use of herbicide-tolerant soybeans, as well as some other points dealing with the availability of data and the different toxicity levels among herbicides.

    Let me indicate a complementary paper (among others) that addresses these issues. This peer-reviewed paper deals with GM crops, herbicide use, glyphosate-tolerant crops, and weed resistance to glyphosate in the U.S., but not with all GM crops, mainly with glyphosate-tolerant soybean. It uses USDA-NASS data as well as some other sources, and has an agro-economic approach.
    Please find here the references as well as a link to this paper :
    Bonny S. 2011. Herbicide-tolerant Transgenic Soybean over 15 Years of Cultivation: Pesticide Use, Weed Resistance, and Some Economic Issues. The Case of the USA.
    Sustainability, 3(9), 2011, pp. 1302-1322.
    DOI:10.3390/su3091302
    Freely available at: http://www.mdpi.com/2071-1050/3/9/1302/

    1. I wonder wehehtr looking at pesticide application per yield gives us useful data or not. If we are concerned with pesticide runoff or impact on the environment, acreage (+toxicity of the chemical) is the critical variable. If we are interested in the amount of pesticide we are ingesting, yield is the right variable. I don’t think that is what he is asking/answering.

  6. Andrew,

    I’m constantly amazed by how out of touch you weed scientists are with the volume of herbicides being used. You’d think with the herbicide-only weed management programs you guys are always pushing, that you’d have a clue at least.

    Your statistical analysis of NASS data for herbicide use on soybean, corn and cotton is no more than a simple linear regression using all available data points from 1995 to 2010, completely uninformed by events on the ground. You say: “If I were going to interpolate or forecast, this would be how I would do it.”

    Why on earth would you assume a consistent trend from 1995, before the 1996 introduction of the first Roundup Ready (RR) crop, and today, when an epidemic of glyphosate-resistant (GR) weeds fostered by those RR crop systems has led to 45-60 million GR weed-infested acres? (Benbrook discusses various estimates, and arrives at this as the mid-range.) The very idea is absurd. Glyphosate-resistant weeds have been by far the biggest factor in weed management and herbicide use trends since wherever RR crops are dominant. They’ve triggered more applications of glyphosate at higher doses, and additional use of other herbicides like 2,4-D and paraquat. And yet in your treatment of Benbrook you say not one word about GR weeds and their effect on herbicide use. Unbelievable. This perhaps reflects your Wyoming experience, one of the dwindling number of states where a GR weed population has yet to be confirmed. Or perhaps your reluctance to discuss facts that reflect unfavorably on your darling RR crops.

    Glyphosate-resistant (GR) weeds emerged in the year 2000. They expanded slowly for 5-7 years, then really began taking off in 2007-2008 and haven’t stopped since. This is based on acreage-infested data, as recorded at http://www.weedscience.com, that I’ve compiled for 5 years now.

    Herbicide use on soybeans and corn bottomed out in 2001 (Andrew, you got the NASS data for cotton wrong, check again), when adoption of herbicide-resistant (i.e. essentially all RR) cultivars of both crops had reached about 70%. As Benbrook explains, initial efficacy of the RR system and lack of GR weeds allowed for a slight decline in herbicide use prior to this.

    The average annual herbicide rate on soybeans rose from 46% from 2001 to 2006 (0.97 to 1.42 lbs./acre). The average annual rate for cotton has risen 60% from 2001 to 2010 (1.66 to 2.67 lbs./acre). These are huge increases in herbicide intensity that primarily reflect increased herbicide use to control dramatically expanding GR weeds in these two crops.

    RR corn has been more slowly adopted. Most growers did not want RR corn, because there are many alternative herbicides in corn. Monsanto forced the RR trait on farmers by putting it in most of their varieties together with Bt, which was more attractive to farmers, for “triple-stack” corn. In its efforts to get farmers to adopt RR corn, Monsanto also told them that continual Roundup use would NOT foster GR weeds, which of course they knew was false. See http://www.weeds.iastate.edu/mgmt/2004/twoforone.shtml for the ugly story, which helps explain why GR weeds have been dramatically expanding in the corn/soybean belt.

    Given the continued rapid expansion of GR weeds, Benbrook is entirely correct to base his projections more on recent herbicide usage trends. This is certainly a much sounder approach than yours, Andrew, which is based on the implicit assumption that nothing’s changed over the past 16 years….

    Several others have mentioned alternative sources of data. They are all private, and cost big money. And they are all inferior to NASS. The gaps in NASS data are due to funding cuts. The program was eliminated for 2008-2009, then thanks to several non-profit groups like my own exerting pressure, we were able to restore funding. For more on the quality of NASS data versus private sources, and the funding cuts, see http://www.centerforfoodsafety.org/2008/05/20/groups-urge-usda-to-reinstate-pesticide-reporting-program/. Chris, Brookes and Barfoot cannot be trusted. They are industry contractors who do “simulation studies” of pesticide use that are not based on statistically valid farmer surveys like NASS and Benbrook. Like Andrew, they make no attempt to deal with glyphosate-resistant weeds and how they’ve driven GR weed increases.

    Readers of this note should be aware that Andrew has prevaricated abundantly in support of his darling crop, Roundup Ready sugar beets, in court declarations on behalf of Monsanto and in comments to USDA. For instance, while telling courts and USDA’s APHIS (in charge of GE crops) that RR sugar beet growers will use “diverse” weed control tactics to forestall glyphosate-resistant weeds, he was telling USDA’s Agricultural Research Service the truth: that RR sugar beets would lead to glyphosate-only weed control programs and thus rapid evolution of GR weeds. For more on this prevarication, see: http://www.centerforfoodsafety.org/wp-content/uploads/2010/12/RRSB-Partial-Dereg-EA-Science-Comments-BF.pdf. For more on rapidly expanding GR weeds in Roundup Ready sugar beets, RR soybeans and RR corn in Minnesota and North Dakota, see http://www.centerforfoodsafety.org/wp-content/uploads/2012/08/RRSB-FEIS-comments-7-9-12.pdf. According to Andrew, this was not supposed to happen, but it is happening, with a vengeance.

    Bill Freese, Science Policy Analyst
    Center for Food Safety

    1. Hi Bill,
      Thank you for stopping by to comment! Since you have a WHOLE lot to say, and the comment/reply system on our blog theme is a little klunky, I’m going to break up my response into quite a few different replies. This way I can respond to each of your points without everyone getting lost with respect to your quotes and my responses.

      First: my goodness, you certainly start off with a super congenial tone!

      Bill Freese: “I’m constantly amazed by how out of touch you weed scientists are with the volume of herbicides being used. You’d think with the herbicide-only weed management programs you guys are always pushing, that you’d have a clue at least.”

      We’re trying to keep this blog pretty focused on facts, rather than attacks. So I guess I’ll just ignore that you began by accusing me of being “out of touch”, and “always pushing herbicide-only weed management programs.”

    2. Bill Freese: “Your statistical analysis of NASS data for herbicide use on soybean, corn and cotton is no more than a simple linear regression using all available data points from 1995 to 2010, completely uninformed by events on the ground. You say: “If I were going to interpolate or forecast, this would be how I would do it.” ”

      Indeed I do use a simple linear regression using available data points from NASS. Simple linear regression is a pretty typical way of conducting a trend analysis, especially when the data set is small. It appears that Dr. Benbrook uses the same method, with the only difference being that I use all the available NASS data Dr. Benbrook lists in his supplemental file, whereas he uses only a subset of that data.

    3. Bill Freese: “Why on earth would you assume a consistent trend from 1995, before the 1996 introduction of the first Roundup Ready (RR) crop, and today, when an epidemic of glyphosate-resistant (GR) weeds fostered by those RR crop systems has led to 45-60 million GR weed-infested acres? (Benbrook discusses various estimates, and arrives at this as the mid-range.) The very idea is absurd. Glyphosate-resistant weeds have been by far the biggest factor in weed management and herbicide use trends since wherever RR crops are dominant. They’ve triggered more applications of glyphosate at higher doses, and additional use of other herbicides like 2,4-D and paraquat. And yet in your treatment of Benbrook you say not one word about GR weeds and their effect on herbicide use. Unbelievable. ”

      I assume a constant trend, because that is what a trend analysis does. It finds the trend in the data. Simple as that. The idea is not “absurd” or “Unbelievable.” I prefer to use data to support my conclusions, not speculation. Glyphosate resistant weeds are indeed a problem in some regions, but there is simply no data (that I’m aware of, anyway) to support the herbicide use increase that Dr. Benbrook assumes. Might this be true? Perhaps. But simply saying something is true, then making up data that support your assertion, then using your made up data to support your conclusions don’t “prove” that you are correct. I acknowledge that I am working from the same incomplete data set as Dr. Benbrook. I simply chose to not make up data to support any pre-conceived conclusions.

    4. Bill Freese: “This perhaps reflects your Wyoming experience, one of the dwindling number of states where a GR weed population has yet to be confirmed. Or perhaps your reluctance to discuss facts that reflect unfavorably on your darling RR crops.”

      I’m always happy to discuss facts. The point of this post was simply to illustrate some potential shortcomings in Dr. Benbrook’s analysis, not to write a dissertation on the status of weed management in the US. If you’d like to discuss facts, feel free to give me a call sometime. My office number is pretty easy to find.

    5. Bill Freese: “Glyphosate-resistant (GR) weeds emerged in the year 2000.”

      You are incorrect. Glyphosate resistant rigid ryegrass was documented in five separate populations prior to 2000 (in Australia and California). Goosegrass was documented as being glyphosate resistant in Malaysia in 1999. A full list of glyphosate resistant weeds can be found here: http://www.weedscience.org/Summary/UspeciesMOA.asp?lstMOAID=12&FmHRACGroup=Go

      Bill Freese: “They expanded slowly for 5-7 years, then really began taking off in 2007-2008 and haven’t stopped since. This is based on acreage-infested data, as recorded at http://www.weedscience.com, that I’ve compiled for 5 years now.”

      Nobody is disputing that cases of glyphosate resistant weeds are increasing. But just because this is happening doesn’t necessarily mean that herbicide use also goes up. It may actually decrease total herbicide use if growers use less glyphosate and instead substitute other products with lower use rates. But again, this is a major limitation of simply counting “pounds on the ground.” Also when you say “that I’ve compiled for 5 years now” it kind of sounds like you’re compiling the data for the http://www.weedscience.com website. I just want to clarify for my readers that the website is actually http://www.weedscience.org, and that it is not associated with the Center for Food Safety.

    6. Bill Freese: “Andrew, you got the NASS data for cotton wrong, check again”

      I actually didn’t get the NASS data wrong. I didn’t track down the actual NASS data for this post, I simply used the Supplemental Table that Dr. Benbrook submitted with his article. If the data are wrong it is an error introduced by Dr. Benbrook. Please let me know what exactly is wrong about the cotton data, and I would be happy to share the correction with Dr. Benbrook.

    7. Bill Freese: “The average annual herbicide rate on soybeans rose from 46% from 2001 to 2006 (0.97 to 1.42 lbs./acre).”

      This perfectly illustrates why we need to base “trends” on more than just 2 years of data. Why did you choose 2001 to calculate the change in herbicide use? Was it because it was the lowest number in the data set and made your increase more impressive sounding (WOW! 46%!)? Using only 2 years and calculating the difference makes it easy to “cherry pick” data that suit your conclusions. For example, I could just as easily look at the corn data and say that herbicide use decreased 30% between 1996 and 2002; or dropped a remarkable 16% in just 1 year from 2001 to 2002. Or that Roundup Ready corn resulted in a decrease of 15% between 1996 and 2010. Lots of different possibilities when we choose 2 arbitrary years for comparison.

      By conducting a trend analysis with all available data, I don’t get to pick and choose. It is not me making arbitrary guesses about what might happen, the data tells us what is happening. Differences between any 2 years in the data set will be dependent on a variety of things: weather patterns, new herbicide products being released, new seed varieties, etc. This is what Nate Silver would probably refer to as the “noise.” But we’re interested in the “signal”, which is what the trend analysis finds. (I’d suggest Nate Silver’s book for some leisure reading if you’d like to learn more: http://www.amazon.com/dp/159420411X)

    8. Bill Freese: “The average annual rate for cotton has risen 60% from 2001 to 2010 (1.66 to 2.67 lbs./acre). These are huge increases in herbicide intensity that primarily reflect increased herbicide use to control dramatically expanding GR weeds in these two crops.”

      Where did you get 1.66 for the year 2001? Dr. Benbrook’s supplemental table shows herbicide usage in cotton of 1.90 in 2001. As I’ve already described, choosing 2 arbitrary years is not a very scientific way to calculate the change. But if we’re going to choose 2 years, why 2001? The first glyphsoate-resistant weed to affect cotton was Palmer amaranth, which was documented in 2005. So how do you explain the use of 2.1 lbs/A of herbicides used in 1997? There were no glyphosate resistant weeds in the region in 1997. So there is no reason to think that 2.1 lbs is outside the realm of “normal” when it comes to the amount of pesticides that might be applied to cotton. If we use this figure to calculate the change, herbicide use increased by 28%, not 60%. As I said in the post, I think the cotton numbers Dr. Benbrook has are probably pretty accurate. But it is a little dishonest to attribute a 60% increase in herbicide use to glyphosate-resistant weeds.

    9. Bill Freese: “RR corn has been more slowly adopted. Most growers did not want RR corn, because there are many alternative herbicides in corn. Monsanto forced the RR trait on farmers by putting it in most of their varieties together with Bt, which was more attractive to farmers, for “triple-stack” corn.”

      Once again, I’d like to remind you that we want to stick with facts on this blog. But this is at least a testable hypothesis. You go find as many farmers as you can that will testify that the RR trait was “forced” on them. I will find as many farmers as I can that are wiling to testify that they wanted the trait, and willingly paid for it. I’ll buy you a soda if you find more farmers than me. Also, even if a grower buys corn seed with the RR trait, they are in no way obligated to spray the crop with glyphosate.

    10. Bill Freese: “Chris, Brookes and Barfoot cannot be trusted. They are industry contractors who do “simulation studies” of pesticide use that are not based on statistically valid farmer surveys like NASS and Benbrook. Like Andrew, they make no attempt to deal with glyphosate-resistant weeds and how they’ve driven GR weed increases.”

      Wow… did it just get ironic in here? I’m actually giggling right now from reading that. “Brookes and Barfoot cannot be trusted” because “they are industry contractors who do “simulation studies” of pesticide use”. The very same thing could be said of Dr. Benbrook. Although he is now working at a center within Washington State University, Dr. Benbrook conceived and wrote this report (at least several previous iterations of it) while working for the Organic Center, whose stated goals are to “Contribute to a measurable increase in organic production and consumption.” and “Achieve revenue objectives through new and creative funding strategies.” (http://www.organic-center.org/about.mission.html) He has also been “commissioned by Greenpeace” to write reports (http://occupy-monsanto.com/tag/charles-benbrook/). So you’re saying we shouldn’t trust people who are funded by industry, but we can totally trust someone who is funded by a different, competing industry? Let’s stay away from the ad hominem attacks, shall we?

    11. LAST ONE!
      Bill Freese: “Readers of this note should be aware that Andrew has prevaricated abundantly in support of his darling crop, Roundup Ready sugar beets, in court declarations on behalf of Monsanto and in comments to USDA. For instance, while telling courts and USDA’s APHIS (in charge of GE crops) that RR sugar beet growers will use “diverse” weed control tactics to forestall glyphosate-resistant weeds, he was telling USDA’s Agricultural Research Service the truth: that RR sugar beets would lead to glyphosate-only weed control programs and thus rapid evolution of GR weeds. For more on this prevarication, see:http://www.centerforfoodsafety.org/wp-content/uploads/2010/12/RRSB-Partial-Dereg-EA-Science-Comments-BF.pdf. For more on rapidly expanding GR weeds in Roundup Ready sugar beets, RR soybeans and RR corn in Minnesota and North Dakota, see http://www.centerforfoodsafety.org/wp-content/uploads/2012/08/RRSB-FEIS-comments-7-9-12.pdf. According to Andrew, this was not supposed to happen, but it is happening, with a vengeance.”

      “Prevaricated?” I had to look that up in the dictionary. “Prevericate: verb. Speak or act in an evasive way.” So I guess we’re back to ad hominem attacks? First, if you’re going to accuse me of lying, why not just say it? Second, sugarbeet growers do use diverse weed control tactics. How many sugarbeet growers do you know? I know quite a few. And they all rotate crops, they almost all use tillage, they almost all rotate herbicide modes of action. You began this comment by accusing me of pushing “herbicide-only weed management programs.” But now you’re ignoring the multitude of other practices sugarbeet growers use for weed management?

      And finally, what you claim was me “telling USDA’s Agricultural Research Service” as “the truth” was actually an abstract from a grant proposal where we described a worst case scenario that “could potentially result in near total reliance on a single herbicide for weed management” in the sugarbeet crop. You are being dishonest when you make it sound like I thought that it was LIKELY result. If I thought it were a likely scenario, I would have chosen much stronger language than “could potentially result.”

      So thanks again for stopping by to comment. But let’s try to stick to facts and verifiable information next time, rather than ad hominem attacks and mistruths.

  7. Andrew,

    You are a remarkably patient man. When I need an example of the misleading techniques that activists deploy, I will simply link to your post. I can’t think of anything to add to your thorough shredding of the junk-science-bomb dropped by Bill Freese.

    Steve

  8. Hey, I found this article while searching for information on GMOs. Made me curious. NASS has published more recent results, including the 2012 data: http://www.nass.usda.gov/Surveys/Guide_to_NASS_Surveys/Chemical_Use/2012_Soybeans_Highlights/ChemUseHighlights-Soybeans-2012.pdf
    I am not quite sure what to make of it, since there’s two kinds of glyphosate listed on p. 2. If the first one is the correct one, Benbrook seems to have gotten it quite right.

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