US department of agriculture (USDA) scientists are using a technology known as FTIR-ATR spectroscopy to identify rapidly and with 95 per cent accuracy citrus plant leaves infected with the devastating disease known as citrus greening.
Scientists from the Agricultural Research Service (ARS) in Florida and the agency’s quality and safety assessment research unit have worked together on the project. The disease spreads rapidly in citrus-growing regions as fruit from infected trees drops prematurely or fails to ripen.
The favoured method for detecting citrus greening-infected trees so far is a type of DNA testing called polymerase chain reaction, which is both costly and time-consuming. FTIR uses light to identify chemicals and reactions in a sample. This technology has the potential to detect the disease before visible symptoms occur, and it is cheaper and faster than DNA testing.
To test for the presence of the disease, researchers removed a leaf from a citrus tree, dried it out in a microwave, and ground it into a powder. A very small sample of the leaf powder was placed on top of an ATR plate. The system clearly distinguished citrus greening-infected leaves from healthy leaves. The scientists say more work will be need to differentiate between leaves infected with citrus greening and those infected with other citrus diseases.
