Impact of GM cotton on biodiversity. Impact des cotton GM sur la biodiversité

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1 Impact of GM cotton on biodiversity Impact des cotton GM sur la biodiversité Jörg Romeis Agroscope Reckenholz-Tänikon Research Station ART Zurich, Switzerland

2 Biodiversity is a protection goal! Cartagena Protocol on Biosafety to the Convention on Biological Diversity (2000) Ratified by Burkina Faso in 2003! Annex III The objective of risk assessment is to identify and evaluate the potential adverse effects of living modified organisms on the conservation and sustainable use of biological diversity

3 Why do we care about biodiversity? Largely because of the ecological services it provides Biological control of herbivores Pollination Decomposition

4 GM crops need to be assessed for their potential adverse effects on non-target organisms prior to commercialization Nature Biotechnology 26, (2008)

5 Comparative risk assessment Comparator: Conventional pest control practise; the method(s) to be replaced. Main method of insect pest control in Burkina Faso: insecticides (organophosphates, pyrethroids) - 6 sprays for the control of Lepidoptera (Helicoverpa armigera) - 2 sprays to control other pests Photo courtesy of Carl Pray

6 How can Bt cotton affect non-target organisms? Direct effects Toxicity of the Cry proteins to non-target organisms There is no indication of direct toxic effects of Bt cotton on organisms outside the order of Lepidoptera. O Callaghan et al. (2005) Annual Review of Entomology 50, Romeis et al. (2006) Nature Biotechnology 24, US-EPA (2001) Biopesticide registration action document. Bacillus thuringiensis (Bt) plant-incorporated protectants.

7 How can Bt cotton affect non-target organisms? Indirect effects Reduced competition with target pests Increased plant biomass Example - Increased number of plant bugs in Bt cotton because of higher number of bolls and flowers. Whitehouse et al. (2007) Australian Journal of Agricultural Research 58,

8 How can Bt cotton affect non-target organisms? Indirect effects Reduced competition with target pests Increased plant biomass Consequences for natural enemies due to the effective control of the targe pest

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10 Bt cotton

11 How can Bt cotton affect non-target organisms? Indirect effects Reduced competition with target pests Increased plant biomass Consequences for natural enemies due to the effective control of the targe pest Reduced application of broad spectrum insecticides

12 Bt cotton insecticide use Historically almost half the insecticide used globally was applied to cotton about half applied for Lepidoptera Bt cotton commercial in 1996, now grown for 12 years Average insecticide reduction > 50% in 2007, but variation among countries (Fitt, 2008)

13 Bt cotton - impact on yield and insecticide use (Fitt, 2008) Country N Sprays Pesticide Yield % change (Kg/ha) % change % change Argentina Qaim et al., 2003 USA Williams, 2003; Cattaneo et al., 2006 Australia Fitt 2003, 2005; Pyke 2004, 2007 India to Qaim 2003; Qaim & Zilberman 2003; Bamberwale et al., 2004 China to +19 Pray et al., 2002; Huang et al., 2003; Lu et al., 2002 Sth Africa (sml) to +80 Yousef et al., 2001; Ismael et al., 2002; Kirsten et al., 2002; Bennett et al., 2003; Hofs et al., Kirsten et al., 2002; Gouse et al., Traxler et al., 2001 Sth Africa (lg) Mexico -54 Refs

14 Bt cotton effects on non-target arthropods A meta-analysis Wolfenbarger et al. (2008) PLoS ONE 3(5): e publications 922 independent data points Countries: USA, China, Australia Insecticidal proteins: Cry1Ac, Cry1Ac+Cry2Ab, Cry1Ac+Cry2Aa

15 Bt cotton vs. non-bt cotton (no insecticides) 1.5 Abundance increased Effect size equal in Bt cotton decreased -1.5 or itoid ixed vore vore vore t a d M erbi mni s ti i r t Pre Para H O De Bt cotton (directly or indirectly) affect abundance of predators. Ratio of predators to non-target herbivores was not affected.

16 Bt cotton vs. non-bt cotton (plus insecticides) 8 Effect size Abundance increased 0.0 equal 1.0 or itoid ixed vore vore vore t a d M erbi mni s iti r t Pre Para e H O D in Bt cotton decreased Abundance is influenced by the method used to control the pest targeted by Bt.

17 Non-target herbivore outbreaks Outbreaks of non-target pests have been reported from Bt cotton worldwide These herbivores are not affected by the Cry proteins and not controlled by natural enemies Mainly restricted to sucking pests: mirid bugs, stinkbugs, leaf hoppers, plant hoppers, whiteflies, aphids Insecticides are sometimes required for their control

18 Conclusions Bt cotton does not appear to cause direct adverse effects on non-target arthropods Changes in arthropod biodiversity that are observed are related to the effective control of the target pest

19 Conclusions Compared to conventional pest control (i.e. insecticides) arthropod biodiversity is significantly enhanced in Bt cotton Herbivores not affected by the Cry proteins may reach pest status (and potentially require control)

20 Conclusions Bt cotton is no a silver bullet but one tool in an integrated pest management program

21 Thank you for your attention