ARS | Publication request: Comparison of FTIR spectra between huanglongbing (citrus greening) and other citrus maladies

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 26, 2010
Publication Date: May 4, 2010
Citation: Hawkins, S.A., Park, B., Poole, G.H., Gottwald, T.R., Windham, W.R., Albano, J.P., Lawrence, K.C. 2010. Comparison of FTIR spectra between huanglongbing (citrus greening) and other citrus maladies. Journal of Agricultural and Food Chemistry. v58, p6007-6010.

Interpretive Summary: Citrus plants are highly susceptible to a disease commonly called HLB (Huanglongbing) which is also known as citrus greening disease. This disease has the potential to wipe out most of the citrus groves in the United States. Plants can be infected for up to several years before showing symptoms during which time it may have been passed on to other nearby plants. Currently, the best method for detecting the presence of the disease is a type of DNA testing called PCR (polymerase chain reaction) which is both costly and time consuming. In this paper, FTIR spectroscopy was used to try to distinguish the presence of HLB versus other common citrus diseases. Some diseases and nutrient deficiencies were found to have a similar spectroscopic pattern to HLB and some were more similar to healthy plants. This technique may be able to quickly and cheaply help distinguish when a sick plant has HLB or another disease.

Technical Abstract: Fourier Transform Infrared Spectroscopy has the ability to quickly identify the presence of specific carbohydrates in plant materials. The presence of the disease Huanglongbing(HLB) in the leaves of infected citrus plants has a distinctive spectrum that can be used to distinguish an infected plant from a healthy plant. However, many citrus diseases share similar visible symptoms and are of concern to citrus growers. In this study several citrus diseases and nutrient deficiencies were compared using FTIR spectroscopy. The results indicate that the spectra of some diseases and deficiencies more closely resemble those of healthy plants and some share the carbohydrate transformation that has been seen in the spectra of HLB disease.