U.S. citrus growers have been fighting citrus greening disease for more than 10 years since it was first discovered on U.S. soil in a Florida citrus grove in 2005.

Huanglongbing (HLB), better known as citrus greening, is a deadly disease spread by the Asian citrus psyllid. The only form of prevention for this disease is to treat against the pest.

In recent months, researchers at the Boyce Thompson Institute in New York on the Cornell University campus have identified a new technology to help manage the disease.

After studying the reproductive and feeding habits of the psyllid, they discovered it’s an ideal carrier of bacterium. The research efforts have concentrated on the psyllid itself as a possible link to control.

Michelle Cilia, a research molecular biologist at the USDA Agriculture Research Service and assistant professor at the Bryce Thompson Institute (BTI), and her team of researchers have been studying the protein that makes the bellies of citrus psyllids blue. They have been studying the possible connection it may have with the natural process of spreading the bacterium.

Research indicates that Asian citrus psyllids with blue abdomen have high levels of an oxygen-transporting protein called hemocyanin.

“For many decades, scientists lacked the ability to look inside insects that transmit plant pathogens and understand what is going on,” Cilia told Southwest Farm Press. “This is no longer true, thanks to the painstaking work of our collaborators in the Bruce and MacCoss labs at the University of Washington. The new molecular tools developed by our University of Washington colleagues enable us to dissect the vector-pathogen relationship piece by piece to determine which components are important for transmission.”

Authors of the study and USDA Agricultural Research Service’s postdoctoral associates suspect the increase in hemocyanin, and the blue color it imparts to the abdomen, could be evidence of an immune response to the bacterium Candidatus Liberibacter asiaticus (or Clas) infection.

This bacterium forces the psyllids to ramp up production of hemocyanin.

The results of this study raise the possibility that this response could be used to help control the bacterium’s spread.

“The study is allowing you to look at your population of insects and say something about the immune system of the insect based on its color,” said John Ramsey, USDA ARS postdoctoral associate. “There’s the possibility that this could be a useful part of grove surveillance.”

Ramsey said this approach to control citrus greening may provide a longer lasting solution than killing the insect.

Antibacterial management and control, management of the psyllids that carry the disease and tree removal have also became a standard procedure to help curtail the rapid spread of the bacterium.

Other management efforts to slow the disease include heat treatments in nurseries and on field trees covered by plastic wrap.

Texas citrus growers also voted to pass the Texas Citrus Referendum in November to help provide the tools growers need to combat diseases and pests that threaten the industry. Citrus has a longstanding history in the Lone Star State and the total value of the industry to the Texas economy is more than $200 million.