by Marlowe Hood Agence France-Presse A bacterial infection ravaging olive orchards in southern Europe can be detected from small planes or drones well before symptoms appear, offering panicky growers the prospect of an early warning system, scientists said Monday. Using high-tech cameras that detect heat and the electromagnetic spectrum from X-ray to radio waves, researchers were able to spot diseased trees that, on the ground, still seemed healthy, they reported in the journal Nature […]