Widespread adoption of Bt cotton and insecticide decrease promotes biocontrol services

Over the past 16 years, vast plantings of transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) have helped to control several major insect pests12345 and reduce the need for insecticide sprays156. Because broad-spectrum insecticides kill arthropod natural enemies that provide biological control of pests, the decrease in use of insecticide sprays associated with Bt crops could enhance biocontrol services789101112. However, this hypothesis has not been tested in terms of long-term landscape-level impacts10. On the basis of data from 1990 to 2010 at 36 sites in six provinces of northern China, we show here a marked increase in abundance of three types of generalist arthropod predators (ladybirds, lacewings and spiders) and a decreased abundance of aphid pests associated with widespread adoption of Bt cotton and reduced insecticide sprays in this crop. We also found evidence that the predators might provide additional biocontrol services spilling over from Bt cotton fields onto neighbouring crops (maize, peanut and soybean). Our work extends results from general studies evaluating ecological effects of Bt crops123461213 by demonstrating that such crops can promote biocontrol services in agricultural landscapes.
Nature letter

Genetically modified crops shrink farming’s pesticide footprint

Genetically modified crops have allowed pesticide spraying to be reduced by almost half a million kilograms in the last 15 years. Eric Constantineau

Recent news reports claim one in ten Australians believe the world will end on December 21, 2012, based largely on internet gossip about the meaning of ancient stone carvings from the Mayans of Central America. Such is the disturbing power of frightening myths to influence human belief.

No wonder modern apocalyptic mythology about agriculture, sinister stories about pesticides and assertions that genetic engineering of crops break a biological taboo find a very receptive audience, especially among those who don’t ever go to a modern farm.

In truth, there’s a lot to feel good about in the way modern agriculture is shaping up to the big challenges of the present – reducing carbon emissions, preventing soil erosion and minimising any environmental damage by herbicides and pesticides.

Helping the environment

One of the most significant crop management improvements in recent times has been the increasingly common practice of sowing seeds by direct drilling them into the stubble of the previous season’s crop. This approach forgoes a massive amount of soil tillage with the plough. Such minimum-tillage or no-tillage farming means that much less diesel oil is used in tractors and carbon levels can buildup in the soil rather than be released to the atmosphere.

It’s been estimated that the carbon emission savings from introduction of genetically engineered crops that encourage no-till farming are equivalent to removing 19.4 bn kilogram of carbon dioxide from the atmosphere worldwide. This is equal to the carbon emissions savings from removing 8.6 million cars from the road for one year.

Minimal tillage farming also has several other benefits, such as better moisture retention in the soil and reduction in soil erosion.

Genetically modified insect protected cotton on the left, next to a closely related conventional cotton variety on the right which is showing the damage from heavy insect feeding pressure. Greg Kauter, Courtesy of Australian Cotton Growers Research Association Inc, Narrabri, NSW.

Klik hier voor het volledige Australische artikel. 

Can Genetically Engineered Crops Cause Adverse Effects on Nontarget Organisms?

Various published studies analyzed effects of Bt maize on nontarget insects. Two well-known studies focused on monarch butterflies (1) and on black swallowtails (2). The first, a note to Nature in 1999, was a laboratory study in which monarch caterpillars were fed milkweed leaves dusted with loosely quantified amounts of pollen from a single Bt corn variety. In the second study in 2000, black swallowtail caterpillars were placed different distances from a cornfield planted with a Bt corn variety different from that used in the 1999 study; populations were studied for effects of Bt for seven days. In the first study more monarch caterpillars died when they ate leaves dusted with Bt corn pollen versus leaves dusted with conventional corn pollen. In the second study, no negative effects of Bt pollen were found on numbers of swallowtail caterpillars.

Het volledige artikel met referenties vind je hier.

De toekomst van de landbouw ligt in een hybride aanpak

Meer en meer blijkt uit onderzoek dat er niet 1 antwoord is op de toekomstige uitdagingen om aan duurzame landbouw te doen. Geen enkele techniek of landbouwmodel zal alleen alle problemen kunnen oplossen. Meer en meer gaan dan ook stemmen op dat een hybride aanpak de enige mogelijkheid is, waarbij het beste uit de biologische landbouw gecombineerd wordt met het beste uit de conventionele landbouw. Waar plaats is voor een agro-ecologische optimalisatie, maar ook voor de allernieuwste veredelingstechnieken. Geen enkel systeem of techniek kan op zichzelf een totaaloplossing bieden voor de toekomstige uitdagingen.

Deze week werd opnieuw een artikel gepubliceerd in Nature (nieuwsbericht) door o.a. Jonathan Foley dat specifiek ingaat op het verschil in opbrengst tussen conventionele en biologische landbouw en welke problemen en/of mogelijkheden dit schept. Jonathan Foley is ook de schrijver van, “Can we feed the world and sustain the planet?”, de stappen die hij hierbij beschrijft worden hier schematisch samengevat.

Naar aanleiding van de publicatie van deze studie in Nature werden heel wat artikels aan deze materie gewijd. Andrew Revkin schreef een heel genuanceerde analyse van dit onderzoek met als titel, Study Points to Roles for Industry and Organics in Agriculture. Prof. Pamela Ronald, gekend van Tomorrow’s table, laat haar licht schijnen op deze problematiek die haar nauw aan het hart ligt. Het nieuwsbericht van McGill, waar het onderzoek, in samenwerking met The Institute on the Environment (Universiteit van Minnesota), werd uitgevoerd. Ook in de Los Angeles time verscheen een artikel met een interview met agro-ecoloog John Reganold (Universiteit van Washington). Zijn quote en uitsmijter van het artikel wil ik u zeker niet onthouden.

“People think organic is not going to feed the world,” Reganold said, whose own research has found that organically grown strawberries contain more nutrients than their conventionally grown counterparts. “Well guess what? No one farming system’s going to feed the planet. It’s going to take a blend to guarantee us global food security.”

Veldproef met bladluizen afwerende tarwe

Bladluizen zijn een belangrijke plaag in verschillende gewassen binnen de landbouw. Ze veroorzaken rechtstreekse schade door zich op de plant te voeden, maar belangrijker is dat ze tijdens dit proces ook virussen verspreiden. In Rothamsted, Groot-Brittannië, wordt deze zomer een veldproef gehouden  met een genetisch gemodificeerde tarwesoort die deze plaag op een duurzame manier tracht te bestrijden.

Bladluizen verspreiden bij gevaar een feromoon ((E)-β-farnesene (EBF)) dat soortgenoten waarschuwt en een teken is om die plaats te mijden. Natuurlijke vijanden van de bladluis, zoals parasitoïde wespen, hebben zich gedurende de evolutie aangepast aan dit proces en worden net aangetrokken door dit feromoon. Zij leggen op hun beurt eieren in de bladluizen, waarna de bladluizen sterven. Ook lieveheersbeestjes worden door dit feromoon aangetrokken.

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The role of transgenic crops in sustainable development


The concept of sustainable development forms the basis for a wide variety of international and national policy making. World population continues to expand at about 80 M people per year, while the demand for natural resources continues to escalate. Important policies, treaties and goals underpin the notion of sustainable development. In this paper, we discuss and evaluate a range of scientific literature pertaining to the use of transgenic crops in meeting sustainable development goals. It is concluded that a considerable body of evidence has accrued since the first commercial growing of transgenic crops, which suggests that they can contribute in all three traditional pillars of sustainability, i.e. economically, environmentally and socially. Management of herbicide-tolerant and insect-resistant transgenic crops to minimize the risk of weeds and pests developing resistance is discussed, together with the associated concern about the risk of loss of biodiversity. As the world population continues to rise, the evidence reviewed here suggests it would be unwise to ignore transgenic crops as one of the tools that can help meet aspirations for increasingly sustainable global development.

Volledige artikel vind je hier.

GM maize and the two-spot ladybird: The scientific debate continues

The significance of laboratory results
Hilbeck et al. (2012) write explicitly that the research methods they describe are suitable only for detecting a potential risk. Further studies would have to be carried out to clarify the matter. Back in 2009 they wrote that ladybird larvae in the field would only be exposed to potentially harmful quantities of Bt protein if they fed on Bt maize pollen or on prey such as red spider mites, which accumulate Bt protein. However, they would not come into contact with Bt protein through their usual primary food source, aphids, because aphids only suck up plant sap, which does not contain Bt protein. Hilbeck et al. (2012) do not address the feeding trials that the Romeis group conducted with prey organisms.

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Field assessment of Bt cry1Ah corn pollen on the survival, development and behavior of Apis mellifera ligustica


Honeybees may be exposed to insecticidal proteins from transgenic plants via pollen. An assessment of the impact of such exposures on the honeybee is an essential part of the risk assessment process for transgenic Bacillus thuringiensis corn. A field trial was conducted to evaluate the effect of transgenic Btcry1Ah corn on the honeybee Apis mellifera ligustica. Colonies of honeybees were moved to Bt or non-Bt corn fields during anthesis and then sampled to record their survival, development and behavior. No differences in immature stages, worker survival, bee body weight, hypopharyngeal gland weight, colony performance, foraging activity or olfactory learning abilities were detected between colonies that were placed in non-Bt corn fields and those placed in Bt corn fields. We conclude that cry1Ah corn carries no risk for the survival, development, colony performance or behavior of the honeybee A. mellifera ligustica. Continue reading

The Impact of Genetically Engineered Crops on Farm Sustainability in the United States

Corn, cotton, and soybean that have been engineered to resist insect pests and herbicides are now planted on almost half of all U.S. cropland. An analysis of the U.S. experience with genetically engineered crops shows that they offer substantial net environmental and economic benefits compared to conventional crops; however, these benefits have not been universal, some may decline over time, and potential benefits and risks may become morenumerous as the technology is applied to more crops. Understanding the impacts of geneti- cally engineered crops is vital to ensuring that crop-management practices and future research and development efforts realize the full potential of genetic engineering for commercial as well as public goods purposes, while maintaining the environmental, economic, and social sustainability of U.S. farms.

Online artikel hier, pdf.

Volledige rapport kun je hier downloaden.

Genetically modified Bt maize: New test with bee larvae

Scientists at the University of Würzburg have for the first time investigated how well bee larvae cope with Bt maize pollen under controlled laboratory conditions. The results of their experiments have now been published: Pollen from Bt maize MON810 and from a Bt maize variety that produces three different Bt proteins was not found to have any harmful effect on the sensitive larval stages of bees. The larval test is part of a biological safety research project funded by the German Federal Ministry of Education and Research (BMBF).

Volledig online artikel hier.