Ecological Effects of Transgenic Crops

Transcription

1 Ecological Effects of Transgenic Crops Peter C. Ellsworth, Ph.D. IPM Specialist, University of Arizona & Steve Naranjo, Ph.D. Research Scientist, USDA-ARS, WCRL

2 Disclosure

3 Disclosure Those engaged in the dialog on biotechnology should fully disclose their relationships and opinions up front so that audiences can consider the context.

4 Disclosure Those engaged in the dialog on biotechnology should fully disclose their relationships and opinions up front so that audiences can consider the context. Partial support for my research comes from companies with interests in biotechnology.

5 Disclosure Those engaged in the dialog on biotechnology should fully disclose their relationships and opinions up front so that audiences can consider the context. Partial support for my research comes from companies with interests in biotechnology. The balance of support comes from state and federal sources of competitively available public funds.

6 Disclosure (continued)

7 Disclosure (continued) Biotechnology and its products are neither inherently good nor bad.

8 Disclosure (continued) Biotechnology and its products are neither inherently good nor bad. The specific process and each of its products should be scientifically and independently evaluated.

9

10 Science or Emotion?

11 Science or Emotion?

12 Science or Emotion?

13 Science or Emotion? Proponents and opponents of biotechnology have made ample use of both. However, emotion tends to rule in the court of public opinion.

14 Public Opinion Unintended consequences: pelicans nearly wiped out by DDT, massive radiation leaked at Chernobyl, now butterflies killed by genetically modified corn Full page back cover of blue magazine; Patagonia, 2001

15 Public Opinion The list of environmental damage caused by inadequately tested technologies is long. With genetic engineering unleashed on the world the list may grow much, much longer. We don t yet know all the impacts and dangers of genetic engineering. Shouldn t we find out the risks before we turn genetically modified organisms loose on the world, or eat them in our food?

16 Public Opinion Our species, as yet unable to see the whole, or to know how it works, now stands poised... From Patagonia, 2001

17 Public Opinion Our species, as yet unable to see the whole, or to know how it works, now stands poised......with an X-Acto blade to cheat the outcome: to solve the puzzle by reshaping its pieces to our own devising. From ww.patagonia.com/enviroaction; Patagonia, 2001

18 Public Opinion Our species, as yet unable to see the whole, or to know how it works, now stands poised......with an X-Acto blade to cheat the outcome: to solve the puzzle by reshaping its pieces to our own devising. From ww.patagonia.com/enviroaction; Patagonia, 2001

19 Powerful Imagery

20 Powerful Imagery Mad Cow Disease

21 Powerful Imagery Bikini Atoll

22 Powerful Imagery Asbestos

23 Powerful Imagery Brown Pelican & DDT

24 Powerful Imagery Thalidomide Babies

25 Powerful Imagery And we now have a solid modern history of stuff that s come out of labs that should have stayed there. Patagonia, 2002

26 So What Is The Story? Monarch Butterfly, symbol of nature and wildness in North America.

27 Incredible Annual Migration!

28 Monarchs Feed on Milkweed

29 Bt Corn Sheds Pollen

30 Bt Corn Sheds Pollen Some of which may fall on milkweed plants that serve as hosts for Monarchs.

31 Bt Corn Sheds Pollen Some of which may fall on milkweed plants that serve as hosts for Monarchs. Bt corn pollen may contain some quantity of the Bt endotoxin.

32 Monarchs Are Killed?

33 Monarchs Are Killed? Scientists have shown that larvae are killed when fed milkweed dusted with Bt corn pollen.

34 Monarchs Are Killed? Scientists have shown that larvae are killed when fed milkweed dusted with Bt corn pollen. But how realistic was this study?

35 Monarchs Are Killed? Scientists have shown that larvae are killed when fed milkweed dusted with Bt corn pollen. But how realistic was this study?

36 PNAS: Temporal & Spatial Distribution of Monarchs From Oberhauser et al., 2001

37 PNAS: Temporal & Spatial Distribution of Monarchs Per plant densities of larvae, similar among habitats (i.e., ag. vs. non-ag. lands) From Oberhauser et al., 2001

38 PNAS: Temporal & Spatial Distribution of Monarchs Per plant densities of larvae, similar among habitats (i.e., ag. vs. non-ag. lands) For upper Midwest, most Monarchs are, in fact, produced on agricultural lands! From Oberhauser et al., 2001

39 PNAS: Temporal & Spatial Distribution of Monarchs Per plant densities of larvae, similar among habitats (i.e., ag. vs. non-ag. lands) For upper Midwest, most Monarchs are, in fact, produced on agricultural lands! Regardless of Bt corn, other agricultural practices like foliar insecticide use and weed control could have large impacts on populations of Monarchs From Oberhauser et al., 2001

40 PNAS: Corn Pollen Deposits on Milkweed From Pleasants et al., 2001

41 PNAS: Corn Pollen Deposits on Milkweed Average 171 pollen grains per sq. cm. in corn fields From Pleasants et al., 2001

42 PNAS: Corn Pollen Deposits on Milkweed Average 171 pollen grains per sq. cm. in corn fields Average 14 pollen grains per sq. cm. 6 ft outside of the corn field From Pleasants et al., 2001

43 PNAS: Corn Pollen Deposits on Milkweed Average 171 pollen grains per sq. cm. in corn fields Average 14 pollen grains per sq. cm. 6 ft outside of the corn field One rain removes 54-86% of the pollen From Pleasants et al., 2001

44 PNAS: Corn Pollen Deposits on Milkweed Average 171 pollen grains per sq. cm. in corn fields Average 14 pollen grains per sq. cm. 6 ft outside of the corn field One rain removes 54-86% of the pollen Youngest leaves, the preferred food, have 50-70% lower pollen density than older leaves From Pleasants et al., 2001

45 PNAS: Toxicity of Bt Proteins & Corn Pollen Bt Toxin Cry1F 1st instars on diet Non-Toxic 1st instars on pollen on discs Non-Toxic Cry9C Non-Toxic Non-Toxic Cry1Ac Toxic Non-Toxic Cry1Ab Toxic Toxic (Event 176 only) From Helmich et al., 2001

46 PNAS: Field Mortality of Monarchs From Zanger et al., 2001

47 PNAS: Field Mortality of Monarchs 50% of Monarch larvae died in the first 24 hrs NONE related to proximity to Bt corn From Zanger et al., 2001

48 PNAS: Field Mortality of Monarchs 50% of Monarch larvae died in the first 24 hrs NONE related to proximity to Bt corn But slower growth of Black Swallowtails likely related to pollen exposure for Event 176 (Novartis) only From Zanger et al., 2001

49 PNAS: Field Impact of Cry1Ab (3 events) Exposure Density & Duration Cry1Ab Event 176 Cry1Ab Bt11 Cry1Ab Mon gr. / sq. cm. Weight loss (-18%) gr. / sq. cm. Weight loss (42%) & mortality (40%) NOE gr. / sq. cm. NOE gr. / sq. cm. NOE -- In-field feeding for d NOE NOE From Stanley-Horn et al., 2001

50 PNAS: Field Impact of Cry1Ab (3 events) Exposure Density & Duration Cry1Ab Event 176 Cry1Ab Bt11 Cry1Ab Mon gr. / sq. cm. 67 gr. / sq. cm. 97 gr. / sq. cm gr. / sq. cm. Weight loss (-18%) Weight loss (42%) & mortality (40%) -- NOE NOE NOE Compared to lambdacyhalothrin which killed most Monarch larvae In-field feeding for d NOE NOE From Stanley-Horn et al., 2001

51 PNAS: A Risk Assessment... X From Sears et al., 2001

52 PNAS: A Risk Assessment... Hazard = X From Sears et al., 2001

53 PNAS: A Risk Assessment... Hazard = X Exposure = From Sears et al., 2001

54 PNAS: A Risk Assessment... Hazard = X Exposure = Risk = From Sears et al., 2001

55 PNAS: A Risk Assessment... Hazard = X Acute toxic effects of pollen Exposure = Risk = From Sears et al., 2001

56 PNAS: A Risk Assessment... Hazard = X Exposure = Acute toxic effects of pollen Probability of larvae being exposed to toxic levels in and around corn fields Risk = From Sears et al., 2001

57 PNAS: A Risk Assessment... Hazard = X Exposure = Acute toxic effects of pollen Probability of larvae being exposed to toxic levels in and around corn fields Risk = This two year study suggests that the impact of Bt corn pollen from current commercial hybrids on Monarch Butterfly populations is negligible. From Sears et al., 2001

58 Non-Target Organisms (NTO)

59 Non-Target Organisms (NTO) Search for unintended consequences of technology (e.g., Bt cotton) on biodiversity.

60 Non-Target Organisms (NTO) Search for unintended consequences of technology (e.g., Bt cotton) on biodiversity. Through direct effects, i.e., toxic effects on non-target species,

61 Non-Target Organisms (NTO) Search for unintended consequences of technology (e.g., Bt cotton) on biodiversity. Through direct effects, i.e., toxic effects on non-target species, Or through indirect effects, i.e., through non-target species feeding on intoxicated hosts.