Leaf \'stamp\' could detect crop diseases

Crop diseases could be detected earlier and more easily if a new method that stamps a leaf with a color-changing biosensor is successful. The Bill and Melinda Gates Foundation awarded US$100,000 to Hideaki Tsutsui of the University of California, Riverside, earlier this month (9 May) to develop the early warning system for crop diseases. Tsutsui\'s idea is to print biosensors directly onto maize leaves to detect pathogens such as aflatoxin. If contamination shows up, farmers will be able to isolate a plant to prevent its spread. \"The long-term goal...is to detect multiple plant pathogens or their markers by chemical reactions that turn areas of leaves different colors,\" Tsutsui told Science and Development Network. He likened the basic mechanism to home pregnancy tests, which have areas that turn blue to indicate a positive result.