The challenge of herbicide resistance around the world: a current summary.

Herbicide-resistant weeds have been observed since the early years of synthetic herbicide development in the 1950s and 1960s. Since that time there has been a consistent increase in the number of cases of herbicide resistance and the impact of herbicide-resistant weeds. Although the nature of crop production varies widely around the world, herbicides have become a primary tool for weed control in most areas. Dependence on herbicides continues to increase as global populations migrate away from rural areas to cities and the agricultural labor force declines. This increased use of herbicides and the concurrent selection pressure have resulted in a rise in cases of multiple resistance, leaving some farmers with few or no herbicide options for certain weed infestations. Global population and economic forces drive many farmer choices regarding crop production and weed control. The challenge is how to insert best management practices into the decision-making process while addressing various economic and regulatory needs. This review endeavors to provide a current overview of herbicide resistance challenges in the major crop production areas of the world and discusses some research initiatives designed to address portions of the problem.