A robot dog equipped with a blowtorch could be used to stop weeds growing on farms, potentially offering a replacement for harmful herbicides. Even highly targeted herbicides can cause environmental problems, affecting local wildlife, and "superweeds" are quickly evolving resistance to the most common weed-killers like glyphosate. In search of an alternative solution, Dezhen Song at Texas A&M University and his colleagues have developed a weed control system that uses a brief burst of heat from a propane-powered torch controlled by a robotic arm, attached to a Spot robot manufactured by Boston Dynamics. Rather than incinerate the weeds, the robot is designed to identify and heat up the centre of the plant, which can stop it growing for several weeks, says Song. "The weeds don't die – you just suppress their growth so it gives your crop a chance to fight the weed." The latest science news delivered to your inbox, every day.