Adverse environmental impacts of GE Bt cotton

Chinese experience illustrates the need for international liability rules

Feature story - 4 June, 2002
Research on the Chinese experience with genetically engineered (GE) cotton tells a story of resistant superbugs, emerging secondary pests, diminishing natural enemies, destabilized insect ecology, and increased pesticide use.

Harvest of organic cotton.

A Greenpeace report reviewing the Chinese experience of GE Bt (Bacillus thuringiensis) cotton shows adverse environmental impacts after just five years of commercial growing, concluding that the variety will be ineffective in controlling pests after eight to ten years of continuous production. Bt cotton is the main GE crop variety grown in large-scale commercial production in China.

Laboratory tests and field monitoring conducted by four Chinese state-owned science institutes verify:

- a resistance build-up towards Bt in the main target pest, cotton bollworm: susceptibility of bollworm to the Bt toxin fell to 30 percent after 17 generations under continuous feeding with Bt cotton leaves. The resistance of the bollworm increased 1000 times when the feeding was continued to the 40th generation.

- a significant reduction of the parasitic natural enemies of cotton bollworm.

- an increase of secondary pests: e.g. cotton aphids, cotton spider mites, thrips and others, replaced the cotton bollworm as primary pests in some of the cotton fields.

These factors have forced farmers to continue the use of chemical pesticides, and increased the possibility of outbreaks of certain pests due to the destabilized insect community.

The author of the study, a researcher at the Nanjing Institute of Environmental Sciences, and an advisor for Greenpeace, Professor Xue Dayuan, said:

"The report confirms that the Bt cotton is released to the environment prematurely. After five years of growing, Chinese farmers and scientists are now faced with serious problems and confronted with the fact that too little is known about the interaction of GE crops with the environment. High hopes have been brought crashing down and reality shows that the information from the GE industry has been unsubstantiated."

Bt cotton, a genetically engineered variety containing a gene from soil bacteria inserted to produce a toxin that kills certain types of pests, was first introduced to China in 1997 by Monsanto. It was advertised as a magical fix to pest problems. Since then the area of cultivation has increased to 1.5 million hectares in 2001, which is 35 percent of the total cotton area. Monsanto's Bt cotton accounts for two third of all GE cotton grown in China.

"As farmers growing this GE crop are now finding themselves entangled in Bt-resistant superbugs, emerging secondary pests, diminishing natural enemies, destabilized insect ecology, and the need to keep spraying chemical pesticides to deal with the increasingly uncontrollable situation, will Monsanto deal with any of these problems their lack of precaution have caused?" asked Lo Sze Ping, Greenpeace China program manager.

"The Chinese government has a role in helping the international community to ensure that corporations such as Monsanto are held liable for the damage they are causing by having developed and released GE crops," Lo added.

View the report

"A summary of research on the environmental impacts of Bt cotton in China"