La soia Transgènica fa augmentar l’ús d’herbicida

No és cap novetat, però la Isabel d’Ecologistas en Acción ha fet arribar aquesta notícia.

Adjunto un extracto del Resumen Ejecutivo del último informe de Charles
Benbrook, en el que se analiza la utilización de pesticidas en los
cultivos transgénicos en EEUU a lo largo de los últimos 13 años.

El informe completo, elaborado por encargo del Organic Center, Union of
Concerned Scientists, Center for Food Safety, Cornerstone Campaign y
Greenpeace, entre otras organicaciones, está disponible en:
http://www.organic-center.org/science.pest.php?action=view&report_id=159

El resumen ejecutivo está disponible en
<http://www.organic-center.org/reportfiles/13Years20091126_ExSumFrontMatter.pdf

Algunas de las conclusiones importantes de este estudio son que:

Los cultivos transgénicos resistentes a los herbicidas (RH) han
incrementado el uso de herbicidas en 173,5 millones de kilos durante los 13 años de cultivo.

En los últimos años la utilización de herbicidas en la superficie
cultivada con variedades transgénicas RH ha experimentado un aumento muy acusado, representando el incremento en el uso de herbicidas de las temporadas 2007 y 2008 el 46% del aumento total de los tres cultivos en estos 13 años. De 2007 a 2008 el uso de herbicidas en los cultivos RH aumentó un significativo 31,4%.

Este aumento tan acusado del incremento en el uso de herbicidas en los
cultivos RH se debe principalmente a la aparición y rápida expansión de malezas resistentes al glifosato (tambien a crecientes reducciones en el volumen de herbicidas aplicado en los cultivos no MG).

En las regiones donde los agricultores están luchando ya contra malezas resistentes, expertos de universidades proyectan para 2010 incrementos de hasta 200 dólares por hectárea en los costes asociados a los cultivos RH, con lo q. el margen de ganancia para los agricultores se reduciría drásticamente.

El año 2009 marcará probablemente varios puntos de inflexión en la
tendencia de los cultivos RH. La superficie de soja RH descendió un 1%
respecto al año anterior, y seguramente volverá a descender varios
puntos porcentuales adicionales en 2010. Las razones argumentadas por
los agricultores para abandonar el sistema RR incluyen el coste y los
problemas inherentes al control de malas hierbas resistentes al
glifosato, el rápido aumento del precio de las semillas, los ventajosos precios de venta de la soja no-MG, un rendimiento de la soja RR2 inferior al esperado y al prometido en 2009, y la posibilidad de guardar y resembrar semillas convencionales (una práctica tradicional que la compra de semillas RH/RR convierte en ilegal).

En varios estados la demanda de soja convencional está superando la
oferta, y los agricultores se encuentran con dificultades para encontrar semillas de variedades no transgénicas.

El futuro de los cultivos transgénicos /Bt/ es más prometedor, pero
únicamente siempre y cuando se evite la aparición de resistencias.
Durante estos 13 años, el maíz y el algodón /Bt/ han conseguido
reducciones en el uso de insecticidas que ascienden a un total de 29,1
millones de kilos. Pero ya han aparecido resistencias en una plaga del
algodón, y de relajarse las medidas de prevención (principalmente
refugios) que hasta ahora han dado muy buenos resultados, el peligro de proliferación de insectos resistentes y de una creciente necesidad de plaguicidas (igual q. ha ocurrido con las variedades RH) no puede
descartarse.

SI ALGUIEN PUEDE REVISAR LAS CONVERSIONES DE DATOS NO VENDRIA MAL – CON LAS PRISAS HE PODIDO METER ALGUN GAZAPO – y he dejado los “bushels” sin convertir -resaltado en gris-, pero la proporcion es clara.

———————————————————————

Los datos de este estudio vienen a confirmar la tendencia perversa de
los transgénicos a:

1/ Dependencia de los agricultores en las semillas transgénicas
(desaparecen del mercado las convencionales, dado el creciente monopolio de las semillas por parte de las transnacionales de los transgénicos – y se prohibe guardar semillas a los agricultores incluso cuando no son híbridos).

2/ Dependencia creciente en el uso de pesticidas y mayores problemas de gestión agrícola (y mayores costes) debido a la aparición de malezas (o plagas posiblemente en el futuro) resistentes

3/ Utilización de pesticidas cada vez más agresivos y/o en cantidades
cada vez mayores.

En el caso de los cutlivos insecticidas (Bt), pese a que la estrategia
de prevención en EEUU parece estar dando buenos resultados (por lo que
desciende la _*media*_ de utilización de plaguicidas -subrayo media xq. en anteriores trabajos de Benbrook y otra gente, si mal no recuerdo, se reflejaba q. la aplicación de plaguicidas baja fundamentalmente en cultivos muy intensivos o en zonas muy infestadas por plagas, donde la utilización de plaguicidas era muy alta anterioremente) y se ha conseguido retrasar la aparición de resistencias, hay ya datos de aparición de resistencias en China, en Sudáfrica y en el propio EEUU (aunq. el dato de aparición de resistencia en una plaga del algodón en EEUU también ha sido puesto en cuestión)…
En España, teniendo en cuenta q. no se ha exigido a los agricultores q. cultivan maíz Bt establecer zonas refugios (al menos al principio – ahora no estoy segura- se alegaba q. como la superficie sembrada era pequeña, no hacía falta), no sería de extrañar q. en algunas zonas sí pudiera haber problemas de aparición de resistencias sin que ello se conozca siquiera (dada las carencias de seguimiento).
También hay que tener en cuenta el importante dato de China, de que en los cultivos insecticidas plagas consideradas secundarias ocupan rápidamente el nicho de la plaga controlada por el Bt, con lo cual la eficacia del Bt es muy relativa.

Os adjunto el último trabajo de Tabashnik, revisando el tema de
aparición de resistencias en los cultivos insecticidas, y el de China
con el tema de otras plagas, por si alguien le interesan y no los tiene.

Como era de esperar, los datos de Benbrook han sido cuestionados desde
sectores cercanos a la industria biotecnológica. Al pie os reboto una
nota de GM-Watch en la que se analizan los fallos en la argumentación de los contra-informes aparecidos (algunos de los cuales son criticados por el propio informe de Benbrook). Resalto en rojo los argumentos principales pero no voy a tener tiempo en unos días para traducir más.
Si alguien le interesa esa información en castellano por favor
decirlo a la lista del área.

Un abrazote

isabel

Betreff: GMW: Benbrook on PG Economics’ methodological creativity
Gesendet: Mittwoch, 25. November 2009
Von: GMWatch <gmwatch-daily@gmwatch.eu>

1.PG Economics Ltd studies
2.National Center for Food and Agriculture Policy (NCFAP) studies

NOTE: The recent report, ‘Impacts of Genetically Engineered Crops on
Pesticide Use: The First Thirteen Years’, by Charles Benbrook has
stirred a lot of interest and some attempted rebuttals. All of the
latter – from the Biotechnology Industry Organisation down, seem to draw heavily on the findings of the UK consultancy PG Economics Ltd.

For instance, an article published by the pro-GM lobby group Truth About Trade states, “It’s possible to point to statistics that say the exact opposite [to the Benbrook study]. PG Economics Ltd., a well-regarded English consulting firm, recently issued its own findings and said that the use of pesticides on global biotech acreage has dropped almost 800 million pounds–or nearly 9 percent–during the same period.”
http://www.truthabouttrade.org/news/editorials/board-commentary/15185-
the-business-of-farming

Curiously, although the Truth About Trade article brands Benbook’s study “activist-sponsored”, it fails to mention that PG Economics work in this area is almost invariably funded by the biotechnology industry. It also fails to mention, possibly because like other critics the author failed to read the actual study, that Benbrook includes a review of PG Economics’ work (see below – item 1) within his study.

What’s apparent from Benbrook’s review is the extreme lengths to which
the PG Economics’ analysts have had to go to come up with their
conclusions. This includes such “creative – and highly questionable –
methodological strategies” as disavowing their own “data-driven
estimates”. (item 1)

This is not the first time PG Economics has been accused of
methodological creativity in achieving their results.
http://www.spinprofiles.org/index.php/PG_Economics

Any such creativity might perhaps owe its origin the passionate
commitment they, and those around them, display towards GM crops.
According to one press report:

“A presentation by Graham Brookes, director of the England-based PG
Economics Limited, showed hard evidence of the overwhelmingly positive
economic and environmental impacts of the crops. Mind you, this is a man whose company gets a paycheck from such pro-GM trade associations as CropLife International and Green Biotech Europe, and who summed up his view of the Indian environmental activist Vandana Shiva with the couplet ‘bloody idiot.'”
http://www.spinprofiles.org/index.php/PG_Economics

Incidentally, Brookes’ co-director at PG Economics, Peter Barfoot, heads an organisation with the motto: “Serving the biotechnology industry”.
http://www.spinprofiles.org/index.php/PG_Economics

It’s sometimes claimed that some of PG Economics work has been “peer-
reviewed”. But such claims are based on publication in the Journal of
Agrobiotechnology Management & Economics – otherwise known as
AgBioForum. AgBioForum has such enthusiastic GM proponents as C. S.
Prakash on its editorial board and is funded by the Illinois-Missouri
Biotechnology Alliance who say their purpose is “to fund biotechnology
research… directed at expanding the volume of profitable businesses in the US food and agricultural sector”.
http://www.spinprofiles.org/index.php/PG_Economics

Below we include Benbrook’s review of PG Economics’ studies, and also
his review of studies by the National Center for Food and Agriculture
Policy (NCFAP), whose work PG Economics draw on. (Note that in the
Benbrook study he reviews the work of NCFAP ahead of that of PG
Economics – we’ve reversed the order).

To access the Benbrook study:
Full report – pdf (3.68 MBs, 69 pages)
http://www.organic-center.org/reportfiles/13Years20091116.pdf
Executive Summary – pdf (1.44 MBs, 15 pages)
http://www.organic-center.org/reportfiles/EXSUM_13Years20091116.pdf


1.PG Economics Ltd Studies

A UK based consulting firm, PG Economics Ltd., has carried out several
studies of GM crops funded by the pesticide and biotechnology
industries. Their latest was released in May 2009. The PG Economics
report uses methods and sources similar to NCFAP [dealt with earlier –
see below], and claims its estimates are based on “the average
performance and impact recorded in di?erent crops.”

The PG Economics report estimates a 4.6% reduction worldwide in
herbicide use attributable to GM crops from 1996 through 2007 (the first 12 years of commercial use). This report [Benbrook’s] estimates that GM HT [Herbicide Tolerant] corn, soybeans, and cotton have increased herbicide use in the U.S. by 382 million pounds over 13 years, or by about 10% (NASS [the USDA’s National Agricultural Statistics Service] reports that 3.82 billion pounds of herbicides applied to these three crops from 1996-2008). It is worth noting that the increase in 2008 -the extra year covered by this analysis – was 100 million pounds, or about 26% of the total increase over the 13 years.

The methodology in the PG Economics report is worth a closer look. HT
soybeans are by far the most important GM crop in the U.S. in terms of
impacts on pesticide use, and so the focus herein is on the PG Economics analysis of herbicide use on conventional and HT soybeans.

The authors begin by noting that there are two primary sources of data
on pesticide use in the U.S. – NASS surveys and private farm-level
surveys (survey data from DMR Kynetec was used in the PG Economics
report).

Their Table 33 reports herbicide use on HT and conventional soybeans for 1998 through 2007 in the U.S., based on Kynetec survey data. In every year, herbicide use was higher on HT soybeans than conventional
soybeans. The margin was typically less than 0.2 pounds until 2002, when the margin increased to around 0.3 from 2003-2007.

Estimates of herbicide use on HT soybean acres as reported in the PG
Economics report and this analysis di?er modestly, and are accounted for largely by the rate per crop year of glyphosate herbicides. Likewise, the PG Economics and this report’s estimates of total herbicide use on conventional soybean acres, and the di?erences between HT and conventional acres, are relatively close for 1998 through 2004. The Kynetec dataset then projects increases in the total rate of herbicide application on conventional acres from 2004 through 2007, despite the continued trend toward greater reliance on relatively low-dose herbicides, as evident in the projections based on NASS data.

This deviation in estimates of herbicide use on conventional soybeans
accounts for this report’s progressively larger margin of di?erence in
herbicide use rates on HT in contrast to conventional soybean acres.

Despite some di?erences, it is significant that the industry-sponsored
Kynetec survey, as reported by PG Economics, supports the same basic
conclusion as this report – HT soybeans have increased herbicide use by a substantial and growing amount.

*But curiously, right after reporting the Kynetec results in Table 33,
the authors of the PG Economics report state:

“The comparison data between the GM HT crop and the conventional
alternative presented above is, however, not a reasonable representation of average herbicide usage on the average GM HT crop compared with the average conventional alternative for recent years.”

The PG Economics analysts disavow their own data-driven estimates,
asserting that herbicide use is lower on conventional soybean acres in
the Kynetec dataset because the majority of farmers planting
conventional soybeans must be among those facing the lightest weed
pressure. This creative argument, however, is incompatible with the
pattern of adoption of HT soybeans across the states. Since 2006, the
rate of adoption of HT soybeans varies modestly between states from 81% to 97%, with no clear pattern between states with relatively low weed pressure (Minnesota, South Dakota) and states with much higher levels of weed pressure (Mississippi, Arkansas).

After rejecting the Kynetec survey findings that were based on real data, the PG Economics team then turns to another source for supposedly more reliable estimates – the National Center for Food and Agricultural Policy [see below]. The PG Economics team revises its soybean herbicide use projections drawing on NCFAP’s faulty simulations, and reaches the basic finding of a 6.8% reduction in herbicide use as a result of HT soybeans.

Similarly creative – and highly questionable – methodological strategies are employed by the PG Economics team in projecting the impacts of other GE crops on pesticide use. Like the NCFAP, the PG Economics team never explains the discrepancies between their estimates and those based on NASS data.
*
NB: The findings of the PG Economics report were featured at the
Biotechnology Industry Organization (BIO) 2009 conference and
subsequently used by most biotechnology and pesticide industry trade
associations in public relations e?orts designed to promote awareness of the benefits of GE crop technology. Note that in [a] posting [on the BIO website, 21 May 2009] by Michael Phillips, BIO Vice President for the Food & Agriculture program, the PG Economics report is highlighted as a “counter” to the 2004 UCS report on the impacts of GM crops on pesticide use over the first nine years of commercial use.


2*.National Center for Food and Agriculture Policy (NCFAP) studies

Several studies by the National Center for Food and Agriculture Policy
(NCFAP), an organization funded in part by the biotechnology industry,
have addressed the impact of GM crops on pesticide use. The most recent report was released in November 2006 and projects impacts in crop year 2005.

NCFAP’s general method is to simulate pesticide use on GM and non-GM
crops by simply extrapolating from particular pest management systems
recommended by university extension agents for adoption on all GM and
non-GM crop acres. Such simplistic models are highly vulnerable to
error, since actual pest management systems often are not the same as
those recommended by university specialists.
*
NCFAP on corn

NCFAP estimates that GM HT corn was planted on 35% of corn acres in
2005, a considerably higher share compared to NASS’s (the USDA’s
National Agricultural Statistics Service) corresponding figure of 26%.
Based on this 35% figure, NCFAP estimates that GM HT corn reduced
herbicide use by 21.8 million pounds in 2005, or about 0.8 pounds per acre.

This finding rests largely on two faulty assumptions that exaggerate the amount of herbicide applied to conventional/non-HT corn acres, which in turn inflates the “reduction” from a switch to HT corn.
These faulty assumptions relate to the extent and rate of use of two high-dose herbicides, atrazine and s-metolachlor/metolachlor, that are used on both HT and conventional/non-HT corn.

With regard to extent of use, NCFAP assumes that all non-HT corn farmers apply two premixed products: first, a mixture of the high-dose herbicides s-metolachlor and atrazine (preemergence), followed post-emergence by a product consisting of mesotrione, nicosulfuron and rimsulfuron. NASS data demonstrate clearly that the atrazine-metolachlor premix could not have been used by a majority of, much less all, farmers planting non-HT corn.
According to NCFAP, non-HT corn comprised 65% of national corn
acres, while NASS reports that just 25% of all corn was treated with
either s-metolachlor or metolachlor, so that at most 25% of corn acres
were treated with this premix. At most, 38% of non-HT corn acres could
have been treated with this high-rate premix.

NCFAP assumes that non-HT corn farmers apply the s-metolachlor/atrazine premix at 3.16 pounds of active ingredients per acre, and the low-dose post-emergence mix at 0.07 pounds per acre, for a total of 3.23 pounds per acre. However, NASS reports that the average amounts of atrazine and s-metolachlor applied to all corn in the 2005 season were 1.13 and 1.35 pounds per acre, respectively.
Accordingly, the combined average rate of atrazine and s-metolachlor applied via the premix was at most 2.48 pounds of active ingredient per acre, much less than the 3.16 pounds assumed by NCFAP.

NCFAP projects that an average of 2.5 pounds of herbicides were applied on RR corn acres in 2005, resulting in a 0.73 pound per acre reduction (3.23 pounds on conventional acres, minus 2.5 pounds on RR acres). NCFAP would have projected a 0.02 pound increase on HT acres had it used the more realistic NASS application rates for atrazine and s-metolachlor on conventional corn. The methodology in this report projected a 0.01 pound reduction in per acre herbicide use on HT acres in 2005.

NCFAP on HT soybeans

In the case of soybeans, NCFAP both underestimates herbicide use on HT
acres and overstates the amount applied to conventional acres. These
faulty assumptions result in a simulated and illusory “reduction” of
20.5 million pounds nationally from the planting of HT soybeans in 2005.

NCFAP wrongly assumed that one application of glyphosate sufficed for
over 80% of Roundup Ready soybean acres, resulting in a simulated 1.18
glyphosate applications to the average RR soybean acre for the year. In contrast, NASS reported an average of 1.5 applications of glyphosate (28% higher), a figure that reflects the need for two or more glyphosate applications to control resistant weeds in many states. Similarly, NCFAP’s estimate of total herbicide applied to RR soybeans – 1.03 pounds per acres per year – does not even match the annual NASS figure for glyphosate alone, which is 1.1 pounds per acre, much less account for non-glyphosate herbicides applied to RR soybeans.

NCFAP assumes, for reasons not explained, that herbicides in addition to glyphosate were applied to RR soybeans in just one state (Iowa). In Iowa, NCFAP assumes that soybean farmers apply 0.19 pounds per acre of Canopy (a premix of chlorimuron and metribuzin), in addition to one application of glyphosate. In contrast, this report (Benbrook’s) more realistically estimates that non-glyphosate herbicides were applied to RR soybean acres at an average rate of 0.12 pounds per acre in 2005.

NCFAP also vastly overstates the amount of herbicides applied to
conventional soybean acres in 2005, assuming average total applications of 1.35 pounds per acre (all presumed to be non-glyphosate herbicides).
This presumed rate for herbicides applied to conventional soybean acres is more than twice the rate of 0.59 pound per acre on conventional soybeans estimated in this study, based on NASS data. NCFAP’s estimate of average herbicide use on conventional soybeans is clearly out of step with the trend toward lower-dose herbicides, some of which are applied at rates well below 0.1 pound per acre.

If NCFAP had used NASS data to work out herbicide use on RR and
conventional soybean, it would have arrived at a result much closer to
the one in this report: an estimated increase in herbicide use of 41.5
million pounds in 2005 due to the planting of RR soybeans.

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