All farmers want to keep an eye on their crops. Now scientists at a Chinese university have developed a wide-view imaging system that uses the fluorescence of chlorophyll to monitor the health of agricultural crops. Chlorophyll is the vital pigment that absorbs solar energy and drives photosynthesis in plants. While a good portion of that absorbed energy goes into photosynthesis, a fraction of it is emitted as fluorescence, and scientists can use measurements of that fluorescence to detect plant stress.