PNAS, vol. 103(20), pages 7571-7576

Farm-scale evaluation of the impacts of transgenic cotton on biodiversity, pesticide use, and yield

Manda G. Cattaneo, Christine Yafuso, Chris Schmidt, Cho-ying Huang, Magfurar Rahman, Carl Olson, Christa
Ellers-Kirk, Barron J. Orr, Stuart E. Marsh, Larry Antilla, Pierre Dutilleul, and Yves Carrière
May 16, 2006

Abstract:

Higher yields and reduced pesticide impacts are needed to mitigate the effects of agricultural intensification. A 2-year farm-scale
evaluation of 81 commercial fields in Arizona show that use of transgenic Bacillus thuringiensis (Bt) cotton reduced insecticide use,
whereas transgenic cotton with Bt protein and herbicide resistance (BtHr) did not affect herbicide use. Transgenic cotton had
higher yield than nontransgenic cotton for any given number of insecticide applications. However, nontransgenic, Bt and BtHr
cotton had similar yields overall, largely because higher insecticide use with nontransgenic cotton improved control of key pests.
Unlike Bt and BtHr cotton, insecticides reduced the diversity of nontarget insects. Several other agronomic and ecological factors
also affected biodiversity. Nevertheless, pairwise comparisons of diversity of nontarget insects in cotton fields with diversity in
adjacent noncultivated sites revealed similar effects of cultivation of transgenic and nontransgenic cotton on biodiversity. The results
indicate that impacts of agricultural intensification can be reduced when replacement of broad-spectrum insecticides by
narrow-spectrum Bt crops does not reduce control of pests not affected by Bt crops.

Thanks Agronomist,
GM Bt cotton produces its own Bt insecticide to kill caterpillars and there is a continuous supply of plant-produced Bt insecticide being released to kill specific caterpillars. The insecticide applied to kill non-target pests on cotton will not be reduced because the other insects are controlled with insecticide applications. If the Bt released by the plant was measured and included, it is likely that there would actually be an increase in chemical released to the environment.
Herbicide tolerant varieties encourage the use of specific herbicides, the myth that Ht crops reduce herbicide applications is wrong as this report indicates.
And of course this report confirms that there is no yield improvement with GM cotton.

Bt MAIZE IN SPAIN FOUND TO IMPROVE PRODUCTION BY 7.3%

Scientists of the Institute and Agricultural Research and Technology (IRTA) of Catalonia report an average increase in Bt maize production of 7.3%, equivalent to 1,055 kilograms per hectare, when compared to non biotech varieties. In addition, the experts reported an increase in the quality of the grain, with an 83% decrease in the level of mycotoxins found in transgenic seeds, and increased grain moisture content during harvesting. The biotech varieties were also reported to have increase tolerance to fungal pathogens. More than 53,000 hectares of transgenic Bt maize were cultivated in Spain in 2005. The study also confirmed that a buffer zone of 15-20 m between Bt maize and conventional crop varieties is sufficient to insure coexistence and prevent the flow of the transgene.

I have tried now for a month to track down report of a 7.5% increase in productivity. I do not want a pundit site or Monsanto site. I want to check to see if all rules of science have been adhered to. In previous reports, I have found major issues that create the illusion of GM improvement over non-GM. An example:- "Outcrossing frequencies and distribution of transgenic oilseed rape in the nearest neighbourhood".

This 35 page report I found shows that the science is manipulated to make GM look acceptable and even fantastic to farmers. Experiment was done for two years (not long enough to show the full implications of cross-contamination), no wind speed given which would indicate that if it is in a valley there would be a reduction in contamination, decrease in flowering in second year of 14 days, the amount of plots allocated in second year of experiment was reduced to 1 GM plot due to labour and space limitations (was this on purpose).

"Another so far neglected factor for the establishment of specific rules concerning co-existence between GM and non-GM crops is the effective detection limit of analytical methods for quantitiative GMO diagnostics. This limit is caused by the amount of DNA that is introduced into the PCR reaction and depends on the genome size of the investigate species."

"Therefore our results cannot be transferred to conditions in large-scale experiments." also "Nevertheless, as shown in this study the effects of the pollination vectors wind and insects are often interacting especially at short distances and can therefore not be predicted completely by models. Therefore field trials providing real data are still necessary for the final determination of the gene dispersal of transgenic crops."

I want to know all the factors and so far all you've said is that is that there is an increase in GM over non-GM in Spain (by the way, wasn't GM meant to be 30% increase in productivity from brochures selling GM). There is a far cry from manipulation and reality when it comes to GM crops and their scientific methods it seems.

If GM maize was as good as you say Agronomist, far more American farmers would be growing it... but they do not. American farmers are well aware that the increase in cost and the restricted market access does not outweigh the "benefits" which is why GM maize growers are a minority.
Most of the yield advantages in GM is because of the non-GM varieties the GM trait is added to, not the trait itself.

NonGMFarmer, Insect-resistant corn has been adopted by farmers in the US. In 2006, 40% of the US corn acreage was sown to insect-resistant corn, up from 35% in 2005 (see: http://usda.mannlib.cornell.edu/usda/nass/Acre//2000s/2006/Acre-06-30-2006.pdf). The adoption rates are higher in some states that have greater pressure from earworm, rootworm or corn borer. Given that in 2005, only 23% of the corn acreage in the US received an insecticide application (see: http://usda.mannlib.cornell.edu/usda/nass/AgriChemUsFC//2000s/2006/AgriChemUsFC-05-17-2006.pdf) down from 30% in 1997, insect pests are not a major concern in corn growing in the US. Therefore, you would expect that adoption of insect-resistant corn would not be that high. The product is less widely used because there is not the need for it.

Just because the US corn growing has low insect pressure, does not mean everybody else has and insect-resistant corn can be more valuable in other areas.