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GM Herbicide Tolerant Crops Escalate the Herbicide Arms Race

Immediate release 19 January 2010

GM Herbicide Tolerant Crops Escalate the Herbicide Arms Race

Farmers urged to take lead on herbicide resistant weeds and adopt non-chemical approach

A new report [1] on the spread of herbicide resistant weeds in the world calls upon farmers to take the lead in dealing with the problem if scientists and governments fail to do so. Without such action GM herbicide tolerant crops will cause an explosion of herbicide resistant weeds.

Promises from agri-biotech companies that GM herbicide tolerant crops would make weed control in crops such as soya, maize and cotton easier and cheaper now look hollow. This year the GM industry will again try to use the ISAAA report to paper over the cracks and paint GM as a success in world agriculture. This research shows exactly how much more costly HT crops are becoming over time as serious problems spread.

GM Freeze has reviewed the latest evidence on weeds resistant to one or more weed killers in the report published today. The rapid increase in weed resistance, and the key role played by GM herbicide tolerant (GMHT) crops that encourage farmers to depend on one herbicide (Monsanto's Roundup), are highlighted. Overuse of Monsanto's best selling product on monocultures employing zero tillage has created the conditions for weeds to evolve resistance very rapidly.

Three examples of Roundup resistant weeds highlighted in the report (Johnsongrass in Argentina, Horseweed and Palmer amaranth in the USA) are now all resistant to Roundup and infest thousands of acres where GMHT soya is grown. Farmers are attempting to control them using cocktails of weed killers, which in Argentina includes spraying them from the air. This has serious implications for the local people and environment because spray drifts off target into villages and other crops.

The report also highlights the problem of weeds with multiple resistance to two or more different types of weed killers, including Roundup, in the US soya and maize belt. The options to rotate the use of different weed killers, to spray mixtures of weed killers or to use soil acting weed killers to kill off problem weeds as they germinate are limited by weeds that have already evolved resistance during decades of chemical weed control.

The complexity of planning weed control on all crops will increase as resistance grows. Weed control costs are rising steeply. There is no prospect for development in the next 5-10 years of an effective, new, safe chemical weed killer to substitute for Roundup or other products with resistance problems.

The report calls for greater use of agroecological methods of weed control, including cover crop planting (such clover), crop rotation, crop breaks, mulching with cover crops and other organic materials and mechanical methods. It concludes:

'The weed control and monoculture systems adopted for GMHT crops ignore these good agricultural principles and practices despite the fact that "farmers who practice continuous cropping, or intensive cropping, run a much greater risk of developing resistance".'[2]

Pete Riley of GM Freeze said:

"We are fast running out of chemicals that kill weeds thanks to overuse and poor farming practices. GM herbicide tolerant crops are accelerating the problem, and before too long chemical weed control options could be very limited in some areas. It only requires one weed to develop Roundup resistance for chemical use to escalate. People in Argentina are already facing frequent bouts of aerial spraying with mixtures of weed killers. This is not good for people, the environment or farming.

"Farmers need to make certain that non-chemical weed control methods are being developed in research institutions. They cannot rely on agro-chemical companies and governments to solve a problem they helped create, as all they have to offer is yet more chemicals. We need a revolution in agricultural research and arable farming to make sure we put an end to the pesticides arms race and adopt sustainable approaches to weed control based on agroecology."