U.S. regulators will put new restrictions on glyphosate, the world’s most widely used herbicide, in an effort to address the rapid expansion of weeds resistant to the chemical. According to Reuters, the Environmental Protection Agency (EPA) confirmed it will require a weed resistance management plan for glyphosate, the key ingredient in Monsanto’s Roundup weed-killer. The EPA has not yet given details but Reuters reports that the measures will include weed monitoring, farmer education and remediation plans. The requirements could be similar to those placed on a new herbicide product developed by Dow Chemical. The company must report to the EPA about cases of weed resistance and inform farmers and other stakeholders about the difficulties of controlling them. The area of U.S. cropland infested with glyphosate-resistant weeds has expanded to 61.2 million acres (24.7 million hectares) in 2012, up from 40.7 million acres in 2011. Not only are glyphosate-resistant weeds expanding geographically; the rate at which they are spreading is gaining momentum, increasing 25% in 2011 and 51% in 2012. These so-called superweeds, such as horseweed and Palmer amaranth, hinder crop production and lead to an increase in herbicide use. According to the U.S. Department of Agriculture (USDA), at least 283.5 million pounds (128,000 tonnes) of glyphosate were used in U.S. agriculture in 2012, up from 110 million pounds (49,000 tonnes) in 2002. USDA says that more than 90% of the soybeans and cotton grown in the United States last year, and 89% of the maize, was genetically modified to withstand herbicide use. The EPA’s announcement comes in the wake of a finding by the World Health Organization’s cancer research unit earlier this month that glyphosate is “probably carcinogenic to humans”, a conclusion based on a review of years of scientific evidence. However, the EPA’s restrictions only focus on the herbicide’s contribution to weed resistance and are not intended to address public health concerns. Last week, several leading non-governmental organisations urged the Obama administration to “weigh heavily” the WHO conclusion. In a letter to the EPA, the organisations called the WHO announcement “extremely timely, as EPA is preparing to issue its preliminary risk assessment of the widely used herbicide“. For the required reevaluation of the herbicide health data will also be taken into account. (ab)