Imagine a tractor-size machine that can tell the difference between a vegetable and a weed – and then zaps the unwelcome plant with a laser. 

It's not science fiction. It's being tested in New Jersey by Rutgers University scientist Thierry Besançon.

An associate professor with the Department of Plant Biology in the School of Environmental and Biological Sciences, Besançon recently collaborated on field trials of the high-tech device that uses artificial intelligence and lasers to kill weeds without using chemicals.

"It's pure physics," he said. "There's no herbicide involved. It's just light energy targeting the weeds."