Genetically engineered crops are often broken down into two categories, herbicide tolerant and plant-incorporated protectants (PIPs). In addition, crops are also engineered or “stacked” to express multiple traits, such as crops that are resistant to multiple herbicides or are resistant to herbicides and incorporate insecticides. In all these cases, the characteristics are achieved through the manipulation of genetic composition of the organism by adding specific genes.
PIPs are created when scientists take the gene for a specific pesticidal protein and introduce the gene into the plant’s genetic material. Then the plant continuously expresses the pesticidal protein that kills the pest when it feeds on the plant. Both the protein and its genetic material are regulated by the Environmental Protection Agency (EPA). The plant itself is not regulated.
In 1995, EPA registered the first Bacillus thuringiensis (Bt) plant-incorporated protectant for use in the U.S. Since then, EPA has registered 11 Bt plant-incorporated protectants, although five of these registrations are no longer active. Corn and cotton Bt incorporated varieties were introduced in 1995 and a Bt variety of soy was registered in 2010.
Despite industry claims that PIPs would lessen pesticide dependency, insects have exhibited resistance to the engineered crops. This raises concerns about the efficacy of natural Bt
used in organic food production and the loss of an important tool.
Target insect or plant resistance is a predictable consequence of repeated pesticide use, as has been since with the use of antibiotics. How quickly pesticide resistance develops depends on the frequency of use, the mechanisms of resistance, the size of the gene pool, and the rapidity of the organism’s reproductive cycle.
- Reports of resistance to certain varieties of Bt-incorporated plants have been widely reported. A study, “Severe Corn Rootworm Injury to Bt Hybrids in First-Year Corn Confirmed”, by Joe Spencer, PhD, and Michael Gray, PhD, released August 2013,identified significant damage from western corn rootworms in farm field that were planted with GE corn incorporated with a Bt protein referred to as “Cry3Bb1,” which has been inserted into nearly one-third of the corn planted in the United States.
- In 2011, entomologists Aaron J. Gassmann, Jennifer L. Petzold-Maxwell, Ryan S. Keweshan,Mike W. Dunbar at Iowa State Universitypublished “Field-Evolved Resistance to Bt Maize by Western Corn Rootworm”, a study verifying the first field-evolved resistance of corn rootworm to a Bt toxin. The researchers documented resistance to the Bt toxin Cry3Bb1. The study found the western rootworm’s ability to adapt was strongest in fields where Bt corn was planted for three consecutive years and suggested that insufficient planting of refuges may have contributed to the resistance. This study was cited by a group of 22 prominent entomologists who submitted formal comments to EPAon their concerns of the viability of Cry3Bb1 corn.
- A January 17, 2013 release from EPA concluded that, “Corn rootworm may not be completely controlled by Cry3Bb1 in certain parts of the corn belt.” After this release EPA did little to mitigate resistance beyond announcing that Monsanto had committed to conduct grower education programs demonstrating the value of crop rotation.
- A 2013 study, “Potential shortfall of pyramided transgenic cotton for insect resistance management”, by Thierry Brévaul, PhD and colleagues, found that stacking sever Bt-incorporated traits does not stop resistance. Researchers assumed that caterpillars resistant to the first Bt toxin would survive on the on-toxin plants, but die when consuming two-toxin plants because they had not yet developed resistance to the new forumulation. However, caterpillars selected for resistance to one toxin survived significantly better than caterpillars from a susceptible strain.
Older Insecticides Brought Back
- According to a report by the Wall Street Journal in 2013, insecticide sales soared in 2013 as target insects have developed resistance to crops GE to incorporate an insecticide. Pesticide manufacturers American Vanguard, FMC Corp, and Syngenta have all reported higher sales in 2012 and 2013 than in previous years. Syngenta alone reported doubling sales in 2012. Similarly, American Vanguard reported soil insecticide revenues rose by 50% in 2012. "The whole industry has seen a resurgence," said Aaron Locker, marketing director for FMC, in the Wall Street Journal report, which has annual revenue of more than $3 billion.
Environmental and Food Contamination
- In a 2011 study “Evidence of reduced arbuscular mycorrhizal fungal colonization in multiple lines of Bt maize”, researchers at Portland State University Tanya E. Cheeke, PhD, Todd N. Rosenstiel, PhD, and Mitchell B. Cruzan, PhD found that the cultivation of GE corn, which expresses the insecticidal soil bacterium Bt, has negative impacts on beneficial soil life. Their findings show a decreased presence of the beneficial fungi in the roots of Bt corn when compared to non-Bt corn. These findings were the first demonstration of a reduction in Arbuscular mycorrhizal fungi (AMF) colonization in multipleBtmaize lines grown under the same experimental conditions and contribute to the growing body of knowledge examining the unanticipated effects ofBtcrop cultivation on nontarget soil organisms.
- A 2010 study, by University of Notre Dame ecologist Jennifer Tank, PhD and colleagues reveals that streams throughout the Midwest are contaminated with transgenic materials from corn crop byproducts. “We found that corn crop byproducts were common in agricultural streams and that 86 percent of sites contained corn leaves, cobs, husks and/or stalks in the active stream channel,” Dr. Tank said. She continued, “In addition, using a sensitive laboratory test that specifically measures the amount of Cry1Ab protein from Bt corn, we detected Cry1Ab in corn collected from 13 percent of the stream sites. We also detected Cry1Ab dissolved in stream water samples at 23 percent of the sites, even six month after crop harvest.
- In September 2000, residues from StarLink,TM a variety of GE corn only registered for domestic animal feed was detected in taco shells, indicating that it had entered the human food supply. In response to these detections. Aventix requested cancellation of StarLink’sTM registration, and the Food and Drug Administration 9FDA) recommended that dry grains mills processing yellow corn test for the presence of Cry9C, Residues were verified again in 2003.
Human Health Risks
- A 2011 study “Maternal and fetal exposure to pesticides associated to genetically modiﬁed foods in Eastern Townships of Quebec, Canada”, conducted by Aziz Arisa and Samuel Lebla conducted at the University of Sherbrooke in Quebec, Canada found that the Cry1Ab toxin, which is an insecticidal protein produced by certain varieties of Bt-incorporated crops, was detected in 93% of maternal blood samples, 80% of fetal blood samples and 69% of the nonpregnant women’s blood. None of the women in the study had ever worked or lived with a spouse that worked in contact with pesticides. The diet of the women involved in the study is described as “typical of a middle class population of Western industrialized countries.”
- A 2010 study, “A Comparison of the Effects of Three GM Corn Varieties on Mammalian Health”conducted byJoël Spiroux de Vendômois and other colleagues at the Committee of Research and Information on Genetic Engineering (CRIIGEN) and the Universities of Caen and Rouen in France found that three varieties of Bt-incorporated corn crops show varying levels of adverse health effects, primarily in the liver and kidneys, in addition to the heart, adrenal, spleen and blood cells. The study sharply criticizes Monsanto’s data analysis and safety conclusions, and calls for additional long-term studies in at least three different mammals.
Risks to Organic
Bt, commercially available for organic farming, is a preparation of weakened or most often dead bacteria. The bacterium inside the spray contains the pro-form of the so called Bt toxin. This is not an active component, it needs to be tailored (cut to size) to produce the active Bt toxin, which is effective as a pesticide. When the insect eats the dead bacterium, the toxin is partially digested in the insect gut by proteolytic (cutting) enzymes and converted to active Bt toxin. When the bacterium is not eaten by any insects, it degrades in the light and open elements relatively quickly (less than a day). The chances of pests developing resistance to it are very low because all the pests which are exposed to the toxin are affected and eliminated by it.
In GE Bt-incorporated crops, the gene of one or several of the active toxins is transferred to the GE plant and is synthesized and expressed in every single cell of the plant, creating a situation prone to insect resistance. Once the natural toxin is lost to organic farmers as a tool in organic farming systems, it will have serious economic consequences.