For automated, mechanical weed control to work, scientists must teach machines how to distinguish between unwanted vegetation and the crop being cultivated. A new, high-tech system using x-rays to detect tomato stems is under development by UC Davis Cooperative Extension agricultural engineer David Slaughter and USDA Agricultural Research Service researcher Ron Haff. The output from the x-ray detector is input to a microcontroller that controls a pair of pneumatically powered mechanical weed knife blades.

Slaughter and Haff's work was explained this week in an online newsletter produced by