In 2014, Digital Journal reported on how Florida produced only 104 million boxes of oranges in 2013, which equated to only half the quantity compared to 2003. The reason was, and remains, an infection called citrus greening.
Citrus greening or “Yellow Dragon Disease” (Huanglongbing) is a disease of citrus caused by a vector-transmitted bacterium called Candidatus liberibacter. The disease is spread by the leaves of an infected plant spreading towards another plant. The infection leads to a yellowing (mottling) of the leaves of the infected plant. After this, defoliation occurs and, eventually, the plant dies.
There are, until the latest research, no known cures. The main way of managing the issue is through using DNA sequencing technologies to assess the early stages of infection and removing infected plants from the area to avoid the affected plant from infecting others.
To find a way to treat infected plants, University of Florida scientists are experimenting with lasers in conjunction with antibiotics. Studies have found the combination of a laser and antibiotics to be more effective than simply applying antibiotics.
With the technique, lasers are directed at a precise power setting to the cuticle of an infected citrus leaf. The laser beam creates microscopic indentations onto the surface of the leaf. To these, antibiotic solutions are then applied by spraying. The solutions absorb faster into the leaf and appear to be more effective at killing the infectious bacterium.
The mechanism has been studied through the use of dyes. This allows researchers to compare the laser and non-laser applications of the antimicrobial and to measure how fast it reaches the critical area within the leaf, via sap. As the model predicted, the laser treated leaves receive the antibiotic much faster and more effectively.
The research is published in the journal Applications in Plant Sciences. The research paper is titled “The Use of Laser Light to Enhance the Uptake of Foliar-Applied Substances into Citrus (Citrus sinensis) Leaves.”
