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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

Ellsworth/UA

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

Cu

m. a

rth

rop

od

-day

s (5

0 sw

eep

s)

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