Citrus Greening - Concern for Citrus Growers

The Texas Department of Agriculture and the USDA Animal and Plant Health Inspection Service (APHIS) confirmed the first detection in Texas of citrus greening, in January of this year, and this is a destructive plant disease that poses a threat to the state’s citrus industry. The disease was discovered in a tree in a commercial orange grove in San Juan.  The disease poses absolutely NO threat to human health as it affects only the tree and NOT the fruit itself. Although there is no cause for consumer alarm, the disease has caused serious economic damage to the citrus industries in Florida, Africa, Asia and South America. Citrus producers and homeowners with citrus plants are asked to comply with quarantine measures to protect Texas citrus trees. 

            Recently I have had a few local calls from citrus growers with concerns that they were seeing symptoms associated with this disease, thus I thought a review was important. NO cases have been reported locally to date.

 Citrus greening (CG) is a devastating bacterial disease that affects the production, quality, and appearance of citrus trees. It is also known as huanglongbing, or yellow dragon disease.  CG is caused by the bacterium Candidatus Liberibacter asiaticus, which is vectored by an insect, the Asian citrus psyllid (ACP). This disease has been reported in several southeastern US states since 2005 and was confirmed in Texas on January 2012.

There is no cure for CG, but it can be eradicated if detected early.  The best ways to ensure that the disease does not infect trees in Texas are prevention and early intervention. No one should bring in citrus plants from states where the disease and/or ACP have been detected.  Look for symptoms, inspect citrus trees often, and report any symptoms you see to the Texas Department of Agriculture (512-463-7476; or toll free, 800-835-5832).

A tree that is infected by citrus greening will have two or more of the

following symptoms:

-          Blotchy mottling and yellowing of leaves. This is a common symptom of CG and may appear initially on a single shoot or twig.

-          Bunched, narrow leaves, commonly referred to as “rabbit ears.” Small and narrow yellowed and/or mottled leaves grow in a tight arrangement, resulting in a bunchy appearance

-          Twig and branch die-back.  Infected trees may have leafless twigs and/or branches. Trees appear unhealthy because this portion of the tree may be dead.

-          Reduced fruit size. The fruit is stunted and does not continue to enlarge; it remains green to  partially green in color. Mature fruit may appear lopsided or asymmetrical.

-          Premature fruit drop. CG can cause higher than normal fruit drop.

-     Orange-brown discoloration of the internal flesh. This may appear inside the fruit on tissue where it attaches to the tree. The fruit tastesbitter and sour instead of sweet.

Because of the nature of the CG pathogen, diagnosis is confirmed by molecular testing in a la

Due to the nature of CG pathogen, diagnosis is confirmed by molecular testing in a laboratory.  Samples from Nueces County north , should be sent to the Texas Plant Disease Diagnostic Lab in College Station.  For more information on citrus greening or to report a tree that may have the disease, go to saveourcitrus.org. or .visit texascitusgreening.org.