“The claim that genetically modified organisms are the most promising way of increasing crop yields is falsified by many independent scientific studies, as well as direct experience with GM crops in India, China, Argentina and the United States. Dr. Eva Sirinathsinghji reviews evidence on Bt crops.
Rising insect resistance to genetically modified (GM) crops including Monsanto’s biggest selling crop, Bt corn, is threatening their utility and profitability. Insect resistance has prompted a new investigation by the Environmental Protection Agency (EPA). According to documents in the newly opened docket (Docket No: EPA-HQ-OPP-2011-0922) , “severe” damage to corn by rootworm has occurred in four states in the US. Further, the EPA describe Monsanto’s insect resistance monitoring program as “inadequate”. The EPA will collect public information to tackle the damage that could cause serious crop and economic damage. Amidst this investigation, Monsanto are seeing significant falls in their share prices . Comments and information regarding insect resistance can be submitted to the EPA on their website .
In 2010, GM crops engineered to produce insecticidal toxins from the Bacillus thuringiensis (Bt) bacterium, were grown on more than 58 million hectares of land globally . First commercialised in the US in 1996, it is also the only commercialised GM crop grown in the EU, with Spain being the largest producer. Despite their widespread commercialisation, the evidence for their functionality is still elusive, while evidence of their harm to the environment, people’s health, economic security and self-determination is continually mounting.
GM proponents have repeatedly claimed that Bt crops can help combat world hunger by increasing crop yields while reducing pesticide use, thereby providing a more productive and environmentally safe option over traditional varieties. However, as highlighted by a recent report conducted by 20 Indian, Southeast Asian, African and Latin American food and conservation groups representing millions of people, these claims are false. Pesticide use has increased, while GM crop yields are lower than conventional varieties (see  Transgenic Cotton Offers No Advantage, SiS 38) and world hunger is at epic proportions .
Risk assessments of Bt toxins to date have been inadequate, not least due to inexplicable lack of reliable data on the concentrations of Bt toxin produced in plants, including the roots and pollen. The purported efficacy and safety of these products cannot be established when exposure levels have not be reliably determined. A new study reported a standardised method to test Bt toxin levels and still found significant variation in results, highlighting the variability in previous studies . In particular, reports of declining concentrations in the food chain and soils are unreliable and need to be re-evaluated and repeated. Despite these inadequacies in risk assessments so far, evidence of the Bt toxicity to environment and health is steadily accumulating.
The present review summarises all the evidence surrounding the efficacy and safety of Bt crops with regards to pest control, human health and environmental impact.”