 |
WWF Special Report
March 2000
Do genetically-engineered (GE) crops reduce
pesticides?
The emerging evidence says "Not Likely".
The risks and benefits of manipulating gene sequences and inserting
foreign
genes into plants and animals genetic engineering (GE) have been the
focus of
public controversy. Along with increased yields, environmental benefits
have
been major selling points of this new technology. In particular, claims
have
been made that GE crops will reduce pesticide use.
Pesticides have provided certain benefits to agriculture. But there is
ample
documentation that pesticides can harm birds, fish, beneficial organisms
and
other wildlife. They are associated with harm to people's health,
particularly
children who are more sensitive to pesticides. The hazards to wildlife
and
human health, and the availability of alternatives, have led many to question
the extent of society's reliance on chemicals for pest management.
World Wildlife Fund is dedicated to achieving reduced reliance on chemical
pesticides through various approaches including:
· pressing for amendment of the federal pesticide law (the Pest
Control
Products Act) to ensure that pesticides registered in Canada do not pose
an
unacceptable hazard to wildlife and human health
· research on high-risk pesticides and their alternatives to prompt
removal of
obvious threats to the environment
· partnership with farmers to implement Integrated Pest Management
(IPM) and
organic agriculture techniques which rely on ecological processes rather
than
chemical inputs and have the capacity to deliver significant reductions
in the
use of pesticides
· promoting introduction of policies and programs which will dramatically
increase adoption of IPM and organic systems
· consumer and food industry education and collaboration to give
farmers
marketplace incentives to adopt sustainable practices
IPM has been a favoured approach to reducing pesticides. While still
a small
fraction of the land base, conversion to organic agriculture has also
grown at
an astounding rate. Of late, some have argued that rapid commercialization
and
use of genetically engineered crops is an effective way to achieve pesticide
reduction. However, this has been called into question by statistics gathered
in the United States which indicate that, at best, reductions are temporary
and
the environmental and agronomic costs/risks high.
Achieving reduced reliance on, use of and risk from chemical pesticides
requires a 'whole farm' approach to pest management which simply cannot
be
provided by substituting a gene-altered plant/animal can't provide. The
path to
reduced reliance on pesticides will be paved with training in ecological
techniques; programs which provide incentives for adoption of IPM and
organic
agriculture; new products such as natural pest controls, attractants and
growth
regulators; and consumer and market support. WWF is concerned that straying
from this path in the hope of finding a genetic engineering 'short cut'
will
not lead to a pesticide reduction in the end.
This paper reviews the available data on pesticide use associated with
genetically-engineered crops and addresses the question of whether GE
delivers
on the promise of pesticide reduction. We invite comments and discussion
on
this issue in the interest of advancing reduced reliance on chemical
pesticides
in Canada.
THE PROMISE OF GENETIC ENGINEERING
Data from the United States government and other sources show that GE
crop
technology is not delivering on its promise to significantly reduce pesticide
use.
Pesticide use is becoming increasingly controversial as the evidence
of health
and environmental impacts associated with pesticides continues to mount.
Evidence from lab and field studies suggests that both old and new pesticides
have negative effects at even lower levels than previously thought. Pesticides
can also reduce populations of beneficial insects pollinators, nutrient
cyclers, natural pest control agents which are critical to food production.
Other well documented problems with pesticides include human poisonings,
cancer, unintended crop losses, ground and surface water contamination,
reduced
soil quality, and fish and bird kills. The risks that pesticides pose
to
children, who are both more exposed and more susceptible than adults,
have
been
seriously underestimated.
Biotechnology companies have focussed particularly on cotton, corn, soybeans,
potatoes and canola. In conventional agriculture, cotton is one of the
most
heavily sprayed crops. Corn and soybeans also receive heavy applications
of
herbicides, and potatoes and canola are sprayed with many fungicides,
insecticides and herbicides. GE varieties of these crops are now planted
on
over 50 million acres of land in North America. Approximately 60 per cent
of the
Canadian canola crop is planted with GE varieties, as well as over 50
per cent
of the US soybean crop, 50 per cent of the US cotton crop, and 40 per
cent of
the US corn crop.
Given the problems with pesticides, reducing pesticide use for the long
term in
these crops would be beneficial.
IS GENETIC ENGINEERING THE ANSWER?
Most of the GE crops on the market have genes from bacteria inserted
into them
(transgenic engineering). These genes come from bacteria or bacteria are
used
as a carrier for genes from other life forms. The foreign genes give crops
two
kinds of new characteristics: resistance to herbicides, so that the crop
can
now be sprayed with a herbicide that used to kill it; or, the ability
to
produce toxins of a bacterium called Bacillus thuringiensis (Bt), which
will
kill some insect pests of the crop (known as Bt crops).
Proponents of genetic engineering have claimed that, because of this
technology, farmers will not have to spray their crops as much with herbicides
and insecticides. Many individual farmers believe that GE crops have reduced
their pesticide use. When all farms using this technology are taken into
account, however, the story is far less positive.
This paper presents emerging evidence from varietal trials and crop and
pesticide use surveys in 1997 and 1998 in the USA the first data collected
following widespread adoption of the technology. The data indicate that
on
average, there is no consistent pesticide reduction in crops attributable
to
the use of GE crops. This is not surprising as evaluations of agricultural
technologies since the 1960s consistently show that benefits are rarely
realized at the rates originally projected. Based on the survey data available
and emerging evidence from laboratory studies, WWF Canada has identified
six
main reasons why GE crops are not producing the pesticide reductions that
proponents claimed would come about.
WHY AND HOW GENETIC ENGINEERING DOES NOT DECREASE PESTICIDE RELIANCE
1. Herbicide-resistant crops increase use of the herbicide for which
the
crop is
resistant and do not necessarily reduce the use of other herbicides.
Crops genetically engineered to be herbicide-resistant are being promoted
on
the grounds that farmers will get better weed control with lower volume
of
pesticides because they will have a larger window of opportunity to spray.
For
example, they could spray before the crop emerges from the soil and after
the
crop is up, and have a greater ability to match the spray time with the
sensitive stages of weed growth. Proponents claim that having crops resistant
to a less toxic herbicide, which they claim Roundup is, will reduce
spraying of
more environmentally damaging herbicides.
In reality, use of herbicide-resistant varieties may increase the number
of
sprays of the herbicide for which the crop is resistant. This occurs because:
(a) The increased spray window may not result in the application of one
strategically-timed spray, but rather in multiple sprays. For example,
Roundup,
which previously would only have been used as a pre-plant herbicide, can
now be
sprayed a second or third time to control a familiar suite of weeds.
(b) Weeds are adapting to the changed environment, requiring more spraying
to
deal with their altered behaviour. There are now documented cases where
the
emergence of weeds has been shifted by Roundup ReadyÒ plantings,
so that
farmers have to spray a second and third time just to deal with the longer
weed
emergence patterns associated with these GE varieties.
(c) New weeds are now occupying fields of GE crops, requiring sprays
of
Roundup
or other herbicides not previously required to control them. Reports from
Iowa
about Roundup ReadyÒ soybean fields show that at least two weeds
rarely
seen in
previous years now appear with regularity. These new weeds emerge in part
because the traditional weed populations have been eliminated by additional
Roundup spraying.
United States Department of Agriculture (USDA) data from 1996 to 1998,
analyzed
by Integrated Pest Management (IPM) adoption expert Dr. Charles Benbrook,
show
that expanded plantings of Roundup ReadyÒ soybeans resulted in
increased
use of
Roundup each year. Benbrook has calculated, based on soybean varietal
trials in
numerous states, that farmers use two to five times more herbicides (measured
in pounds applied per acre) than those planting conventional soybean
varieties,
and 10 times more herbicides than farmers who practice multitactic Integrated
Weed Management. Benbrook concludes that the full Roundup Ready system
is now
costing farmers "an amazing $68.77 per acre in 1999, about 50% more
than the
cost of [other] seed plus weed management systems in the Midwest in recent
years."
2. Bt crops do not necessarily result in reduced spraying of insecticides
to
control target pests.
Although Bt technology is used in corn, cotton and potatoes, Bt corn
is the
most extensively planted Bt crop, accounting for some 20 million acres
worldwide. Bt corn is designed to control the European Corn Borer (ECB).
The
corn plant continuously expresses Bt toxin which, when ingested along
with
plant tissue, kills the pest. Proponents claim this will provide better
ECB
control with significantly lower insecticide applications.
There are, however, a number of holes in this rationale. The first is
that
most
farmers do not currently spray conventional field corn to control ECB.
Since
ECB is usually only a significant pest problem one year in five on average
in
the USA and one year in three in Ontario, most field corn is not sprayed
most
years. Dr. Ann Clark of the University of Guelph has estimated that Bt
corn
could be considered an alternative strategy to insecticide use on only
one to
two per cent of US corn acres.
Knowing that this rationale for using Bt corn is on shaky ground, proponents
often argue that even if it does not substitute for insecticides, the
technology does provide excellent control. But, if excellent control is
only
required one year in three or five, is it worth spending money on control
that
is not needed?
The economic data suggest not. One Ontario analysis indicates that ECB
would
have to cut yields by at least 58 bu/ac before Bt corn would be economically
competitive. Unless ECB pressures are high, estimated to occur one year
in
three in Ontario, other less costly options are available. Missouri varietal
trials produced similar results, showing no difference in yields of GE
versus
non-GE varieties, but significant differences in profitability. GE varieties
were more costly to use under conditions of low to moderate ECB infestations
because the US$9.00 to $9.50 per acre technology use fee could not be
recouped
through higher yields. The researchers concluded that only high ECB pressures
would make the GE varieties profitable. Comparable results were found
in
Indiana. Furthermore, conventionallybred (non-GE) corn borerresistant
hybrids
perform as well as Bthybrids under lowtomoderate corn borer infestations.
As
well, Clark points out that any comprehensive economic analyses must also
account for the reduced yields that occur in some GE corn varieties, relative
to conventional cultivars, and for the loss of effectiveness that will
result
from increasing ECB resistance to Bt corn (see below).
In addition, many entomologists have pointed out that the introduction
of Bt
corn has heightened farmers' attention to ECB damage. Now many farmers
are
both
planting Bt corn on some acreage and spraying other acres that in the
past
would not have been treated.
Overall, Bt corn is associated with increased spraying of insecticides
for ECB
in the US, not with reductions. According to an analysis performed by
Dr.
Charles Benbrook, using data from the US National Agricultural Statistical
Service (NASS), "acres treated for ECB rose from 9.5% in 1995 to
10.5% in
1998,
despite the planting of some 15 million acres of Bt corn."
Compared to Bt corn, Bt cotton initially appears to offer more promise
of
pesticide reduction. The USDA concluded that in two of three studied regions,
the adoption of Bt cotton reduced the use of some insecticides normally
used on
the pests targeted by Bt. For example, there was a significant decrease
in
aldicarb, but not organophosphate and pyrethroid. However, in one of the
three
regions, total treatments for all cotton pests were actually 53 per cent
higher
for adopters of Bt cotton than non-adopters. In the other two regions
when
looking at all insecticides used, not just those associated with Bt targeted
pests there were no reductions. This raises questions about whether the
technology actually decreases overall insecticide use. Another confounding
factor in assessing the value of Bt cotton for pesticide reduction is
that
growers with the more significant numbers of pests are less likely to
adopt
the
technology. As with Bt corn, for many growers Bt cotton is not a substitute
for
insecticides.
3. GE crops will increase resistance of pests to both pesticides and
the GE
crop
itself.
GE crops will increase the resistance of pests to both pesticides and
the
novel
gene in the crop itself, requiring additional, and potentially more toxic,
sprays than the ones the technology is supposed to help reduce. It is
common
knowledge that repeated use of almost all control agents pesticides,
antibiotics, or GE crops will inevitably lead to a resistant population
of
pests over time. In every population of pests, there are usually a few
that
survive and when they reproduce, they create offspring that are also
resistant.
GE technology does not surpass the adaptive capacity of organisms.
There are now reports from Iowa and the Mid-West that velvetleaf, smartweed,
and waterhemp species of weeds have developed tolerance or resistance
to
glyphosate (Roundup). Weed scientists are predicting that even more weeds
will
become resistant to glyphosate. Many farmers may respond by increasing
their
applications which will lead to even greater resistance pressures or use
of
other, more toxic, herbicides.
Similarly, pests may develop resistance to the novel genetic trait in
the GE
crop. Although resistance to Bt crops has yet to be confirmed in the field,
most believe it to be inevitable. In fact, manufacturers knew that widespread
resistance would occur within a few years. Pest resistance to Bt is
particularly distressing given that when used as a spray a few times a
year as
farmers have done for several decades Bt is quite benign. Widespread
resistance to Bt due to the proliferation of Bt crops will render Bt spray
useless as a control strategy. With its loss, farmers will have to use
more
toxic sprays to replace it.
To forestall the development of resistance to Bt corn and cotton, regulators
and genetic engineering firms are asking that farmers plant non-Bt crops
in
the
vicinity of the Bt varieties. In theory, these "refugia" will
harbour insects
that are not resistant to the Bt crop and when resistant insects mate
with
them, the offspring also will not be resistant. In corn, for example,
it is
now
recommended that at least 20 per cent of acreage be devoted to such refugia.
There are a number of problems with this approach. In corn production,
it is
clear that many farmers have not been complying with the recommendations.
Numerous reports indicate that farmers are reluctant to devote the minimum
20
per cent refugia recommended in the farm locations that are the most important
for implementing this strategy. The situation is better in Canada than
in the
US as the Canadian government and many farm organizations are more actively
promoting the refugia strategy.
Secondly, the refugia strategy assumes that all resistance will be
recessive so
that when resistant corn borers mate in the refugia, offspring will have
a
sensitive phenotype and will be killed by feeding on the genetically
engineered
Bt corn. However, a report in Science has revealed that resistance to
Bt
may be
genetically dominant in the ECB. In theory, this means that resistance
will be
passed on to future generations, making the refugia strategy ineffective.
Researchers are now monitoring field conditions closely for signs of this
effect.
A third key to industry's and government's Bt resistance management
strategy is
to ensure that high doses of Bt toxin are expressed in crops so that nearly
all
ECBs are killed. Studies in Kansas indicate that resistance develops to
moderate levels of Bt toxin. Yet, registrants continue to develop, and
the US
EPA continues to approve, Bt corn varieties that only express moderate
doses of
Bt toxin, an apparent contradiction of their own resistance management
strategy. In Canada, there is at least one Bt corn variety registered
with
moderate dosage characteristics.
The cotton resistance management strategy is also criticized. The
expression of
Bt in cotton varieties is not high enough to kill most of the cotton bollworm,
allowing 10-40 per cent of the insects to survive. This requires a huge
refuge
to create a large enough susceptible population for mating with survivors.
Few,
if any, growers have created such extensive refugia. In contrast to ECB,
evidence to date suggests that in another cotton pest, pink bollworm,
resistance
is recessive. However, one study reported that resistant insects developed
more
slowly than their susceptible counterparts and may therefore be out of
phase
for random mating and dilution of resistance in the field. If so, the
entire
basis for the refuge strategy is rendered less effective.
Even with an effective refugia and high-dose Bt expression strategy,
Bt crops
may only be effective for 10 years, maximum. If the refugia strategy fails,
which is likely, the efficacy of Bt sprays could be lost in as little
as five
years.
What will it cost to lose Bt as a control strategy? Because it is naturally
occurring, Bt is arguably the most important insecticide discovered in
recent
times and its loss would cause growers to switch to more harmful synthetic
pesticides. Used in foliar spray, Bt is critical for many organic farming
and
Integrated Pest Management programs and has been identified by the EPA
as a
safer approach than chemical pesticide alternatives. The EPA has concluded
that
Bt pesticides have low dietary, worker, and ecological risks compared
to the
alternatives that might replace Bt, should resistance develop.
4. Gene flow will increase weediness among close relatives of GE crops,
requiring additional sprays to control them.
One of the main ecological risks of GE crops is the flow of the "foreign"
inserted gene sequences from crops to other organisms. Gene flow may occur
from
plant to plant, from plant to bacteria, and from plant to virus. The gene
sequence which moves may be the novel trait itself, or it can be other
sequences
that are inserted in the crop as part of the engineering process (e.g.,
antibiotic resistance genes, gene promoters that are usually virally derived).
Of particular concern for pesticide use is the flow of herbicide-tolerant
genes
from a crop to a close relative.
Of the crops currently on the market, canola presents a significant
problem, as
it is very closely related to many plants that are considered weeds. For
instance, the main canola variety, Brassica napus (B. napa), is very prone
to
gene flow. It has out-crossing rates of up to 30 per cent with other plants
of
the same species, and also with other related plants (frequently weeds
in
canola fields), including, potentially, B. rapa, B. juncea, B. carinata,
B.
nigra, Diplotaxis muralis, Raphanus raphanistrum (wild radish) and Erucastrum
gallicum. This means that genetically modified versions are at significant
risk
of gene flow. In fact, gene flow from GE canola to closely related canola
varieties and weeds has already been documented.
GE crops in development for example, carrot, squash, sunflower and alfalfa
also present concerns similar to canola because they have close relatives
that
are common weeds. In Canada and the USA, corn, soybeans and cotton have
no
close relatives, so herbicide-tolerance gene flow is considered unlikely
in
these crops.
Such gene flow can complicate weed management and limit options for pesticide
reduction. For instance, in 1998, Canadian farmers reported Roundup
(glyphosate)-resistant volunteer canola plants on fields where none had
been
grown, the result of gene flow from transgenic to conventional canola
plants.
More recently, volunteer canola plants resistant to three herbicide-tolerant
canola systems (i.e., triple resistant) have been found in northern Alberta.
The provincial canola specialist said about this development, "We
know it was
going to happen. It was only a matter of when." As a result, farmers
are
forced
to use chemicals other than glyphosate to control the volunteers, and
of the
available options, several (e.g., 2,4-D, diquat, paraquat) are environmentally
more problematic. If a related weed that is already hard to control, such
as
wild radish, acquires herbicide tolerant traits, then it will be even
more
difficult to manage.
5. GE food crops have negative impacts on beneficial insects which would
otherwise help to control pests.
Several studies indicate that populations of bees, lacewings, ladybugs,
monarch
butterflies, and soil organisms may be reduced by exposure to GE crops.
Harm to lacewings and ladybugs is of particular significance from a pesticide
use perspective since reducing the populations of beneficial insects means
reduced levels of natural pest control. Research conducted at the Swiss
Federal
Research Station for Agroecology and Agriculture found that green
lacewings, an
important predator of many agricultural pests, experienced retarded
development
and 67 per cent greater immature mortality when reared on a diet of European
corn borers fed Bt corn, as compared to those fed borers which fed on
regular
corn. In addition, Bt toxin expressed in transgenic corn can be directly
toxic
to lacewings; lacewing mortality doubled when fed on the Bt corn fed borers
(57% vs. 30% mortality).
Researchers from the Scottish Crop Research Institute found that female
ladybugs that ate aphids fed on genetically modified potatoes laid fewer
eggs
and lived only half as long as ladybugs feeding on aphids that ate non-GE
potatoes. The potatoes were genetically engineered to include a toxin
found in
snowdrops GNA lectin which kills potato aphids. These same GNA lectins
are
being used in GE experiments with grapes, canola, rice, sweet potato,
sugar
cane, sunflower, tobacco, walnuts and tomato. While the transgenic potatoes
suffered reduced attacks, reductions were insufficient to compensate for
the
decreased aphid control performed by ladybugs feeding on the green peach
aphid.
Researchers also found that up to 30 per cent fewer viable eggs were laid
when
one of the parent ladybugs was fed aphids from lectin-transformed potatoes.
This is significant because ladybugs prey on a wide variety of aphids
that are
serious pests in corn, alfalfa, canola, wheat, flax, peas, apples and
potatoes.
A single ladybug larvae can eat 800-1000 aphids before pupating and an
adult
can eat 3000-4000 during its lifetime. Reducing such beneficial insect
populations means more difficulty controlling aphids, and greater
likelihood of
spraying.
Planting GE varieties of food crops as a pest management strategy, as
opposed
to multitactic Integrated Pest Management which is designed to work with
beneficial organisms, has an additional pest control cost that has not
been
calculated in the expenses of using GE technology. The loss of pest control
associated with reducing beneficial insect populations is not subtracted
from
the economic benefits assigned to the use of GE crops.
6. GE crops reinforce poor crop rotation practices.
In the short term, some GE applications may help reduce pesticide use
for some
farmers. But this single tactic approach is not sustainable and although
it
may
work well initially, it may even undermine one of the key approaches to
sustainable pest management crop rotation. Crop rotation is critical to
pest
management because changing the kind of crop grown in a field every year
creates a different, less hospitable habitat for pests. It is more difficult
for pest populations to build up and therefore the need to spray pesticides
is
reduced. Crop rotation is also essential for managing other environmental
problems, including soil loss and reduced water quality.
Growers who may not have been practicing appropriate crop rotation may
now be
turning to GE crops in the hopes of continuing what are fundamentally
unsustainable cropping practices. For instance, potatoes can only be grown
on
the same land once every three to four years, if pest pressures, particularly
Colorado Potato Beetle, are to be minimized. Bt potatoes, designed to
reduce
Colorado Potato Beetle damage, will discourage farmers from practicing
crop
rotations of this length, because it presents the illusion (until inevitable
resistance builds) that control is feasible without such cropping system
changes.
Soybean farmers currently experience more weed management problems than
they
did several decades ago, likely because cultural practices, including
longer
crop rotations, have been abandoned. Rather than recognize that longer
crop
rotation is the root solution to this problem, farmers use GE soybeans.
Similarly, simplified crop rotation is also blamed for increases in European
Corn Borer populations in corn production. Again, rather than practicing
crop
rotation to solve this problem, growers turn to Bt corn.
SUMMARY AND CONCLUSIONS
The bottom line, based on the emerging data, is that GE crops do not
offer
sustainable reductions in use and reliance on pesticides. It appears that
farmers who have planted GE crops are spraying the herbicide for which
the
crop
has tolerance, as well as other herbicides, more frequently than projected
because:
a) they can do so without damaging the crop;
b) they have to contend with weeds that are now resistant to the herbicide
for
which tolerance is conveyed;
c) they have to contend with new weeds appearing in their fields because
of
the
use of GE crops;
d) gene flow transfers herbicide tolerance to closely related weeds.
Farmers planting GE crops also appear to be using more insecticides because:
a) they are not using cultural controls, like longer crop rotations,
to
make it
more difficult for pest populations to exist at economically damaging
levels;
b) insects will become resistant to the GE crop;
c) GE crops likely reduce beneficial insect populations;
d) little attention is being paid to economic thresholds.
Overall, the pesticide reduction benefits have been overstated, the ecological
risks under researched and reported, and the economic costs and benefits
miscalculated. The technology has been misrepresented in ways that suggest
genetic improvement can take the place of management and skill in solving
pest
problems. This may explain, in part, why farmers have so readily adopted
the
technology to the degree they have.
In the context of strategies that reduce use of, reliance on, and risks
from
pesticides which WWF is pursuing, GE food crops are not an appropriate
technology. These crops should not be considered part of Integrated Pest
Management programs. In fact, data suggest this technology holds back
the
transition to IPM. Some analysts predict that GE crops will require even
more
pesticides than conventional crops because the insertion of transgenes
may
weaken the plant's metabolism, rendering it less competitive with pests.
Regulators need to re-assess their licensing decisions for GE crops,
since the
technologies are not performing according to claims, and significant risks
continue to emerge. The US EPA may be forced shortly to confront these
problems
with Bt corn because the existing conditional registrations lapse in April
2001. Canadian regulators should similarly undertake a re-assessment of
Bt
corn
and other GE crops.
ENDNOTES:
Benbrook, C.M. et al. 1996. Pest Management at the Crossroads. Consumers
Union,
Yonkers, NY.
Robinson, A.Y. 1991. Sustainable agriculture: The wildlife connection.
American
Journal of Alternative Agriculture 6:161-167.
Colborn, T. et al. 1996. Our Stolen Future. Dutton, New York.
Hassan, S.A. et al. 1987. Results of the third joint pesticide testing
program
by the IOBC/WPRS - Working Group: pesticides and beneficial organisms.
J.
Applied Entomology 103:92-107.
National Research Council Canada. 1991. Pesticide-Pollinator Interactions.
NRCC
18471, Ottawa.
World Wildlife Fund. 1999. Beneficial Bugs at Risk From Pesticides. Toronto,
WWF.
Jaenicke, E.C. 1997. The Myths and Realities of Pesticide Reduction. Henry
A.
Wallace Institute for Alternative Agriculture, Beltsville, MD.
Pease, W.S. et al. 1996. Taxing pesticides to fund environmental protection
and
Integrated Pest Management. California Policy Seminar, University of
California,
Berkeley.
Using US government data, this conclusion has been drawn by the major
environmental NGO, the Environmental Working Group. See Environmental
Working
Group. 1997. Overexposed: Organophosphate insecticides in children's food.
Washington, DC. Consumers Union. 1999. Do you know what you're eating?
An
analysis of US government data on pesticide residues in foods. Yonkers,
NY.
Based on estimates provided by the USDA and Agriculture and Agrifood Canada.
Ruttan, V.W. 1982. Agricultural Research Policy. University of Minnesota
Press,
Minneapolis, MN.
Note, however, that the negative impacts of glyphosate include negative
impact
on beneficial soil arthropods, particularly beneficial mites and
parasitoids. A
German government review of these effects in December, 1998 may lead to
a full
European Union review of the status of this herbicide.
Moldenke, A.R. 1992. Response of soil invertebrates to management practices
in
ponderosa pine plantations: Herbicide, insecticide and fertilizer. Symposium
volume, Eureka CA Meeting. US Dept Agriculture, Forest Service, Southwest
region, Nov. 1991.
Bergvinson, D.J. 1991. Glyphosate-induced changes in the attack success
and
development of the mountain pine beetle and impact of its natural enemies.
Entomologia experimentalis et applicata 60 (2)203-212.
Clark, E.A. 1999. Debunking the myths of genetic engineering in field
crops.
Alternatives, Kitchener, ON, 2 March.
Benbrook, C. 1999. Evidence of the magnitude and consequences of the Roundup
Ready yield drag from University-based varietal trials in 1998. AgBiotech
InfoNet Technical Paper #1. July 13, 1999.
Dr. Charles Benbrook projects that many farmers in 2000 will have to spray
2-3
times with Roundup and 1-2 times with at least one other herbicide. See
Benbrook, C. 2000. Who controls and who will benefit from plant genomics?
Paper
to "The 2000 Genome Seminar: Genomic Revolution in the Fields: Facing
the
needs
of the new millennium". AAAS Annual Meeting, Washington, DC. February
19,
2000.
Reschke, P. 1999. Era of Roundup Ready likely to change the weedscape.
Ontario
Farmer, Feb. 23, 1999.
Benbrook, C. 1999. Evidence of the magnitude and consequences of the Roundup
Ready yield drag from University-based varietal trials in 1998. AgBiotech
InfoNet Technical Paper #1. July 13, 1999. Multitactic Integrated Weed
Management relies on crop rotation, tillage, smother crops, altered timing
for
seeding, and altered seed bed preparation.
Sustainability and agricultural biotechnology. Rachel's Environment and
Health
Weekly #686. February 10, 2000.
PETITION Submitted to The Honorable Carol Browner, Administrator U.S.
Environmental Protection Agency by the Environmental Defense Fund. Contact:
Rebecca Goldburg, Ph.D., Senior Scientist. July 13, 1999.
Baute, T. 1999. M.Sc. Thesis, University of Guelph. Cited in Button, T.
1999. Bt
corn makes good insurance. Farm and Country, June 21, 1999.
Clark, E. Ann. Ten Reasons why farmers should think twice before growing
GE
crops.
<http://www.oac.uoguelph.ca/www/CRSC/faculty/eac/10reasons.htm>http://www.oa
c.uoguelph.ca/www/CRSC/faculty/eac/10reasons.htm.
Industry research suggests the figure is only marginally higher - 2.5%.
Sears, M. and A. Schaafsma. 1998. Responsible deployment of Bt-corn technology
in Ontario.
<http://www.cfiaacia.agr.ca/english/plant/pbo/btweb2e.html>http://www.cfiaac
ia.agr.ca/english<http://www.cfiaacia.agr.ca/english/plant/pbo/btweb2e.html
>/plant/pbo/btweb2e.html.
Rose, F. 1999. MU tests find comparable yields between Bt, nonBt corn
hybrids.
Nov. 11/99 University of Missouri Press Release,
<http://agebb.missouri.edu/news/queries/showcur.idc>http://agebb.missouri.e
du/news/queries/showcur.idc.
Hyde, J. et al. 1999. The economics of Bt corn: Adoption implications.
Purdue
University Cooperative Extension Service ID219:1-15, West Lafayette, Indiana.
Clark, E. Ann. Ten Reasons why farmers should think twice before growing
GE
crops.
<http://www.oac.uoguelph.ca/www/CRSC/faculty/eac/10reasons.htm>http://www.oa
c.uoguelph.ca/www/CRSC/faculty/eac/10reasons.htm.
Ibid.
Dr. Charles Benbrook, email posting to Genet-net, May 21 and May 25, 1999.
Data from the Economic Research Service of the USDA.
<http://www.econ.ag.gov/whatsnew/issues/biotech/index.htm>http://www.econ.a
g.gov/whatsnew/issues/biotech/index.htm
Benbrook, C. 2000. Who controls and who will benefit from plant genomics?
Paper
to "The 2000 Genome Seminar: Genomic Revolution in the Fields: Facing
the
needs
of the new millennium". AAAS Annual Meeting, Washington, DC. February
19,
2000.
Hartzler, B. 1998. Are Roundup Ready weeds in your future? Iowa State
University
Weed Science Report. Nov. 3, 1998.
Benbrook, C. 1999. Evidence of the magnitude and consequences of the Roundup
Ready yield drag from University-based varietal trials in 1998. AgBiotech
InfoNet Technical Paper #1. July 13, 1999.
For a discussion, see Tabashnik, B. 1997. Seeking the root of insect
resistance
to transgenic plants. Proc. Nat. Academy Sci. 94:3488-3490.
Note that the toxin expressed in Bt crops is not the same as the toxin
produced
from naturally occurring Bt. The GE version, exists in a truncated and
more
active form, does not require the highly alkaline gut of susceptible insects
for activation. This means that the GE version is much less selective,
and can
potentially have an impact on a wider range of non-target species. See
Hilbeck,
A. et al. 1998. Toxicity of Bacillus thuringiensis Cry1Ab Toxin to the
predator
Chrysoperla carnea (Neuroptera: Chrysopidae). Environmental Entomology
27:1255-1263.
When Bt corn was first introduced, the industry/government recommended
refugia
was 5%, then 10%, now 20% and some are recommending 40%.
In response to poor uptake and emerging evidence of refugia strategy problems,
the EPA recently mandated refugia requirements in Bt corn of 20%, 50%
if grown
in cotton growing areas.
Led by Dr. Doug Powell of the University of Guelph and funded in part
by the
Ontario Corn Producers Association, AGCare, the Ontario Bt Coalition,
Pioneer
HiBred Ltd. and Novartis Seeds Inc.
Huang, F. et al. 1999. Inheritance of Resistance to Bacillus thuringiensis
Toxin
(Dipel ES) in the European Corn Borer. Science 284:965967.
Ibid.
Union of Concerned Scientists. 1999. Now or Never: Serious new plans to
save a
natural pest control. Union of Concerned Scientists, Washington.
Liu, YB. et al. 1999. Development time and resistance to Bt crops. Nature
400:
519.
Union of Concerned Scientists. 1999. Now or Never: Serious new plans to
save a
natural pest control. UCS, Washington.
Greenpeace, et al. v. Browner, U.S. District Court for District of Columbia,
Civ. Docket No. 99389 (LFO) (filed February 18, 1999).
Gianessi l. 1995. An economic profile of the U.S. crop protection pesticide
industry. National Center for Food and Agricultural Policy, Washington,
DC.
Janet L. Anderson, Acting Director, Biopesticide and Pollution Prevention
Division, Decision Memorandum, Consideration of Section 3(c)(7)(B) Conditional
Amendment for Northrup King's Bt Corn Plantpesticide, August 2, 1996 at
2.
See, for example, Mikkelsen, T.R. et al. 1996. The risk of crop transgene
spread. Nature 380:31.
Stephenson, J.R. and Warnes, A. 1996. Release of genetically-modified
microorganisms into the environment. J. Chem. Tech. Biotech. 65:5-16.
Ho, M.-W. et al. 1999. Cauliflower Mosaic Viral Promotor A recipe for
Disaster?
Microbial Ecology in Health and Disease 11-14.
Sylvanen, M. 1999. In search of horizontal gene transfer. Nature Biotechnology
17(9):833.
Taken from Monsanto's submission to the Canadian government for unrestricted
field release of Roundup Ready canola.
Jorgensen, R. and B. Andersen. 1995. Spontaneous hybridization between
oilseed
rape (Brassica napus) and weed Brassica campestris: A risk of growing
genetically engineered modified oilseed rape. American Journal of Botany
81:
1620-1626.
Mikkelsen, T.R. et al. 1996. The risk of crop transgene spread. Nature,
380: 31.
Eber, G. et al. 1994. Spontaneous hybridization between a male-sterile
oilseed
rape and two weeds. Theor. App. Gene. 88:362-368.
Damency, H. 1994. The impact of hybrids between genetically modified crop
plants and their related species: introgression and weediness. Mol. Ecol.
3:37-40.
Lefol, E. et al. 1996. Gene dispersal from transgenic crops: II. Hybridization
between oilseed rape and the wild hoary mustard. Sexual plant reproduction
9(4):189196.
MacArthur, M. 2000. Triple-resistant canola weeds found in Alta. Western
Producer, Feb. 10, 2000.
Environmental problems of pesticides are measured by a number of indices.
For a
review, see Levitan, L. 1997. An overview of pesticide impact assessment
systems
(a.k.a. Pesticide Risk Indicators) based on indexing or ranking pesticides
by
environmental impact. OECD Background Paper, Paris, France. Available
at:
<http://www.pmac.net/lois.htm>www.pmac.net/lois.htm.
Crabb, Charlene. 1997. Sting in the tale for bees. New Scientist, 14.
Compeerapap, J. 1997. The Thai debate on biotechnology and regulations.
Biology
and Development Monitor, 32: 13-15. Cited in Hanson, M. & Halloran,
J.
Jeopardizing the Future? Genetic Engineering, Food and the Environment.
<<http://www.pmac.net/jeopardy.html>http://www.pmac.net/jeopardy.html>.
Hilbeck, A. et al. 1998a. Effects of transgenic Bacillus thuringiensis
corn-fed
prey on mortality and development time of immature Chrysoperla carnea
(Neuroptera: Chrysopidae). Environl. Entomol. 27(2): 480-487.
Hilbeck, A. et al. 1998b. Toxicity of Bacillus thuringiensis Cry1Ab Toxin
to the
Predator Chrysoperla carnea (Neuroptera: Chrysopidae). Environ. Entomol.
27(5):
1255-1263.
Birch, A.N.E. et al. 1997. Interactions between plant resistance genes,
pest
aphid populations and beneficial aphid predators. Scottish Crop Research
Institute Annual Report, pp. 68-72.
EPA MRID No. 434635.
Tapp, H. and G. Stotzky. 1998. Persistence of the Insecticidal Toxin from
Bacillus thuringiensis Subsp. Kurstaki in Soil. Soil. Biol. Biochem.
30:471-476.
Saxena, D. et al. 1999. Transgenic plants: Insecticidal toxin in root
exudates
from Bt corn. Nature 402:480.
Losey, J.E. et al. 1999. Transgenic pollen harms monarch larvae. Nature
399:214.
Hilbeck, A. et al. 1998. Effects of transgenic Bacillus thuringiensis
corn-fed
prey on mortality and development time of immature Chrysoperla carnea
(Neuroptera: Chrysopidae). Environl. Entomol. 27(2): 480-487.
Hilbeck, A. et al. 1998. Toxicity of Bacillus thuringiensis Cry1Ab Toxin
to
the
Predator Chrysoperla carnea (Neuroptera: Chrysopidae). Environ. Entomol.
27(5):
1255-1263.
Birch, A.N.E. et al. 1997. Interactions between plant resistance genes,
pest
aphid populations and beneficial aphid predators. Scottish Crop Research
Institute Annual Report, pp. 68-72.
World Wildlife Fund. 1999. Beneficial Bugs at Risk From Pesticides. Toronto,
WWF.
How frequently is determined by a host of ecological factors specific
to each
farm and region. See Coleman, E. 1989. The New Organic Grower. Chelsea
Press,
Chelsea, VT.
Smith, M. et al. 1994. The Real Dirt: Farmers tell about organic and low-input
practices in the Northeast. Northeast Region Sustainable Agriculture Research
and Education Program, Burlington, VT.
Benbrook, C. 1999. Evidence of the magnitude and consequences of the Roundup
Ready yield drag from University-based varietal trials in 1998. AgBiotech
InfoNet Technical Paper #1. July 13, 1999.
Note that GE proponents claim that crop rotation no longer works. However,
they
are referring to very simplified corn-soybean rotations where the ECB
has
adapted to living with soybeans and then has higher populations in the
corn
crop that follows. Corn requires a minimum 3-4 year rotation if these
kinds of
pest pressures are to be avoided. There is ample evidence that such longer
term
rotations can also be economically viable (cf. Welsh, R. 1999. The
Economics of
Organic Grain and Soybean Production in the Midwestern United States.
Henry A.
Wallace Institute for Alternative Agriculture, Washington).
Reports are now emerging from government and university departments showing
how
the economics of GE crops are not as favourable as proponents have presented.
In addition to the problems with GE corn and soybeans presented above,
herbicide-tolerant canola varieties have not offered as significant a
yield
advantage as producers thought, and appear to only offer significant economic
advantages when particularly difficult to control weeds - e.g., cleavers
and
stork's-bill - are present in significant amounts. See Lethbridge Research
Centre Report. 2000. Benefits of Herbicidetolerant Canola Systems Vary,
Study
Shows. January 13, 2000.
Benbrook, C. 2000. Who controls and who will benefit from plant genomics?
Paper
to "The 2000 Genome Seminar: Genomic Revolution in the Fields: Facing
the
needs
of the new millennium". AAAS Annual Meeting, Washington, DC. February
19,
2000.
. Many news reports and surveys suggest that sales of GE seeds will decline
by
15-25% for the 2000 crop year.
Benbrook, C. 2000. Who controls and who will benefit from plant genomics?
Paper
to "The 2000 Genome Seminar: Genomic Revolution in the Fields: Facing
the
needs
of the new millennium". AAAS Annual Meeting, Washington, DC. February
19,
2000.
For more information, please contact:
World Wildlife Fund Canada
245 Eglinton Ave. East, Suite 410
Toronto, ON M4P 3J1
1-800-26-PANDA
www.wwf.ca
|