Free download: Expert review on economics of GM crops

An electronic review that contains high quality information about the economics of GM crops, including economics in developing countries, has become available with free access at Annual Reviews website. The pdf can be currently be downloaded (perhaps only for a limited time).

The Economics of Genetically Modified Crops by Matin Qaim of the Department of Agricultural Economics and Rural Development at Georg-August-University of Goettingen, Germany. Note: “The author is not aware of any affiliations, memberships, funding, or financial holdings that might be perceived as affecting the objectivity of this review.” The research was supported financially by the German Research Foundation (DFG).


Genetically modified (GM) crops have been used commercially for more than 10 years. Available impact studies of insect-resistant and herbicide-tolerant crops show that these technologies are beneficial to farmers and consumers, producing large aggregate welfare gains as well as positive effects for the environment and human health. The advantages of future applications could even be much bigger. Given a conducive institutional framework, GM crops can contribute significantly to global food security and poverty reduction.
Nonetheless, widespread public reservations have led to a complex system of regulations. Overregulation has become a real threat for the further development and use of GM crops. The costs in terms of foregone benefits may be large, especially for developing countries. Economics research has an important role to play in designing efficient regulatory mechanisms and agricultural innovation systems.



  1. Another very recent (29 March, 2011) review (warning, slow download).
    Assessment of the economic performance of GM crops worldwide

    “6. Conclusions
    In the analysis undertaken in this study (raw) data from original papers was re-assessed to find out about trends in results across space, time and different crops and traits. It therefore differs from most other review studies which mostly use overall results from different (case) studies for a comparative analysis.
    Due to the strong variations between regions and the additional varying factors found in the analysis that influence results on the economic performance of GM crops (see above), any generalised conclusions on the economic performance of GM crops for the whole world would inevitably be misleading. However, positive economic effects have been observed for a number of countries, which is in line with other review studies (e.g. Carpenter, 2010, Gouse et al., 2009, Bennett et al., 2004a, Frernandez-Cornejo et al., 2005, and Qaim, 2009) and explains the high adoption rates of GM crops in these countries.
    It must be added that the study found general limitations in the collection of comparable data. In particular, the comparability between studies based on field trials and studies using surveys as a data source is limited and should be taken into account in future research. In addition, other varying factors, such as farms characteristics, crop varieties adopted and seasonal changes of growing conditions, can hamper the conclusiveness of comparative studies between GM and conventional crops because comparisons under equal conditions are difficult to achieve and are rarely made.”

  2. One pitfall it is good to avoid is studies which look at farmer income. Here in the US, GM crops have led to important increases in farmer income — almost entirely because the decrease in crop management time makes it easier to have a “real” job in town.
    It’s in developing countries where the productivity of GM crops leads directly to farmer income.

  3. The 2009 Annual Review “review” states the following:

    “In the first years of Bt crop deployment, it was predicted that insect populations would soon develop Bt resistance, which would undermine the technology’s effectiveness and lead to declining insecticide reductions over time. However, until now, Bt resistance has not been observed under field conditions,…..”

    H.Kuska comment. Apparently a scientific paper was published about Bt field resistence in 2007 First report of field resistance by the stem borer, Busseola fusca (Fuller) to Bt-transgenic maize
    According to Google Scholar the above paper has been cited 36 times (including another 2009 Annual Review “Fitness Costs of Insect Resistance to Bacillus thuringiensis”.
    Here is the most recent paper (April 2011) that I could find on this subject:
    Resistance to Bt Maize in Busseola fusca (Lepidoptera: Noctuidae) From Vaalharts, South Africa
    I like to find the most recent paper since it’s Introducion Section should give a quick historical review of what was done earlier. Here is what they stated:

    “To date field evolution of resistance has been rare and only detected in Busseola fusca (Fuller) (Lepidoptera: Noctuidae) in South Africa (Van Rensburg 2007); Helicoverpa zea (Boddie)(Lepidoptera: Noctuidae) in the southeastern United States (Tabashnik 2008, Tabashnik et al. 2008a); and Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in Puerto Rico (Matten et al. 2008, Storer et al. 2010). Resistance to Bt cotton has also recently been reported in the pink bollworm [Pectinophora gossypiella (Saunders)] (Lepidoptera: Gelechiidae) in India (Monsanto 2010).”

  4. Insect resistance to Bt crops is increasingly viewed as unlikely, due to findings regarding Bt mode of action.
    It’s often said that Bt perforates the gut of the insect, resulting in an insect that’s not able to digest food. But more recent research points in a subtly different direction: perforation of the insect’s gut leads to beneficial gut flora escaping from the gut and infecting the entire insect.
    The result: insects would have to develop resistance to their own beneficial gut bacteria to actually develop Bt resistance. This indicates that insect Bt resistance is highly unlikely.
    Their exists a counterexample, Bt resistance in the diamondback moth, which resulted from organic farmers using Bt sprays indiscriminately. That phenomenon deserves more research, but unfortunately, it’s politically incorrect to examine things which might make organic farming look bad. And try to find funds to research that — no way.
    There’s also a conundrum associated with this. Why do farmers planting Bt crops have to establish refugia, whilst organic farmers spraying Bt sprays don’t have any requirements or restrictions?
    If Bt resistance is a real concern, why do organic farmers get a free pass?

  5. Eric please give references for the sources of your above your statements as many things once thought so may have been found not to be the case. In this specific case you just made a statement about insect resistance that appears to not be consistent with what I posted (with reference). Then you give an example with a diamondback moth that appears to not be consistent with what you just stated. (In a scientific forum I feel it is not too much to ask for actual references when non obvious statements are made.)

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