impact of gmo’s on non-target organisms
DESCRIPTION
Impact of GMO’s on Non-Target Organisms. Peter C. Ellsworth, Ph.D. IPM Specialist, University of Arizona & Steve Naranjo, Ph.D. Research Scientist, USDA-ARS, WCRL. Disclosure. - PowerPoint PPT PresentationTRANSCRIPT
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Impact of GMO’s on Non-Target Organisms
Peter C. Ellsworth, Ph.D.IPM Specialist, University of Arizona&Steve Naranjo, Ph.D.Research Scientist, USDA-ARS, WCRL
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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.
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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.
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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.
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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
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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?”
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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 www.patagonia.com/enviroaction; Patagonia, 2001
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Are Scientists Mad?“For the past decade, biotech’s mad scientists have
been telling consumers not to worry about Frankenstein foods….…The biotech industry and governments have done almost no safety testing of GE foods….…Millions of acres of GE crops are spreading genetic pollution, creating superweeds and pests, disrupting the balance between pests and natural predators, and killing butterflies and beneficial soil microorganisms. The more we learn about Frankenfoods and crops, the scarier they appear.”
From BioDemocracy News #40, “The Death of Frankenfoods”, August 2002
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Powerful Imagery
Mad Cow DiseaseBikini Atoll
AsbestosBrown Pelican & DDTThalidomide Babies
“And we now have a solid modern history of stuff that’s come out of labs that should have stayed there.”
Patagonia, 2002
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GMO’s: Social Platform?• Starbucks Global Week of Action
(Sept. 21-28, 2002)
• Remove genetically engineered ingredients from their food and dairy products on a worldwide basis,
• Improve working conditions for coffee plantation workers, and brew and seriously promote fair trade coffee in all of their cafes.
From Organic Consumers Association; organicconsumers.org
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World Food Deprivation
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A Hungry Planet?• 1.85 Billion people (30%) are hungry in the
world today (FAO, 2002).
• 36 Million people (13%) go hungry in the U.S. today (USDA, 2002).
• 2.5 - 6 Million people (20-50%) starving in Zambia today, yet…
• Zambian President Levy Mwanawasa recently rejected FREE corn (10,000 tons) offered by the U.S., because it was not GMO-free.
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So What Is The Story?
• Monarch Butterfly, symbol of nature and “wildness” in North America.
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Incredible Annual Migration!
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Monarchs Feed on Milkweed
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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.
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Monarchs Are Killed?
• Scientists have shown that larvae are killed when fed milkweed “dusted” with Bt corn pollen.
• But how realistic was this study?
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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
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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
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PNAS: Toxicity of Bt Proteins & Corn Pollen
Bt Toxin 1st instars on diet
1st instars on pollen on discs
Cry1F Non-Toxic Non-Toxic
Cry9C Non-Toxic Non-Toxic
Cry1Ac Toxic Non-Toxic
Cry1Ab Toxic Toxic (Event 176 only)
From Helmich et al., 2001
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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
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PNAS: Field Impact of Cry1Ab (3 events)…
Exposure Density & Duration
Cry1Ab Event 176
Cry1Ab Bt11
Cry1Ab Mon810
22 gr. / sq. cm. Weight loss (-18%)
-- --
67 gr. / sq. cm. Weight loss (42%) & mortality
(40%)
NOE --
97 gr. / sq. cm. NOE --
500+ gr. / sq. cm. NOE --
In-field feeding for 14-22 d
NOE NOE
From Stanley-Horn et al., 2001
Compared to lambda-cyhalothrin which killed most Monarch larvae
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PNAS: A Risk Assessment...
Acute toxic effects of pollen
Probability of larvae being exposed to toxic levels in and around corn fields
Hazard =
Exposure =
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
X
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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.
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Natural Enemy AbundanceNo Insecticides
1999
9 Jun29 Jun
19 Jul8 Aug
28 Aug17 Sep
Cum
. art
hrop
od-d
ays
(50
swee
ps)
0
4000
8000
12000
160002000
9 Jun29 Jun
19 Jul8 Aug
28 Aug17 Sep
0
2000
4000
6000
8000
P = 0.18 P = 0.29Bt cottonNon-Bt
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Natural Enemy AbundanceInsecticides as needed
Bt cottonNon-Bt
UnsprayedSprayed
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Non-Target Organisms (NTO)• Over 370 arthropod species have been tracked in 2
years of field studies using a variety of methodologies.
• So far, no major or functional differences have been found in Arizona between BG, BGII, and conventional cotton communities…
• Except where harsh PBW sprays are needed in conventional cottons.
• Thus, Bt cotton ecosystems are not only safe, but safer than conventional cotton ecosystems where insecticidal inputs are higher.
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Information• All University of Arizona
crop production & crop protection information is available on our web site,
• Arizona Crop Information Site (ACIS), at
• http://ag.arizona.edu/crops
ACIS
http://ag.arizona.edu/crops/presentations/presentations.html