Citrus Greening Continues To Spread In Citrus Growing Areas

Citrus greening or huanglongbing (yellow shoot) is considered one of the most serious threats to the citrus industry. A bacterial disease, citrus greening affects all types of citrus species and causes infected trees to yellow, decline, and possibly die within a few years of infection. Spread by an insect, the Asian citrus psyllid, citrus greening has significantly impacted citrus production in Asia, Africa, and Brazil.

"The threat of this disease spreading to other citrus-growing states definitely exists, especially in places where the Asian citrus psyllid is already found," said Ronald Brlansky, plant pathologist at the University of Florida, Citrus Research and Education Center. In California, researchers are continually looking for evidence of the citrus psyllid. If it is found there, citrus trees will need to be closely monitored for disease symptoms.

Citrus greening can only be managed, not completely controlled. By reducing the psyllid population through the use of insecticides, the spread of the disease may be lessened. Growers are urged to become familiar with the symptoms of huanglongbing, to scout for the symptoms and to send in samples for testing.

Citrus greening has spread from eight to 23 counties since it was first found in Florida just a little more than a year and a half ago. Once citrus trees are infected, the fruit yield, rate, and quality are greatly reduced. The trees also become susceptible to other diseases and health problems. In some areas of Brazil, citrus greening has affected as much as 70 percent of the fruit rate and yield.

The research will be presented at a conference during the joint meeting of The American Phytopathological Society and the Society of Nematologists  that runs July 28-Aug. 1, 2007.