Many new plant varieties that are sold for livestock pasture pose a weed risk that jeopardizes their purpose — the sustainable intensification of agriculture — by increasing the environmental costs of food production. We urge governments to include potential environmental damage when screening new pasture varieties and to introduce a 'polluter pays' penalty system.

More than 90% of new pasture- plant species are invasive weeds with characteristics that include fast growth and wide-ranging environmental tolerance (see D. A. Driscoll et al. Proc. Natl Acad. Sci. USA 111, 16622–16627; 2014). The consequences have been disastrous in some countries, including Australia and the United States, where buffel grass, for example, increases fire risk and transforms ecosystems.

Worldwide, limited regulation of new pasture varieties places the environment at increased weed risk. We suggest that agribusinesses should be held financially accountable for environmental damage that their products cause, providing incentives to stem the threat from invasive pasture plants.