The USDA's National Institute of Food and Agriculture (NIFA) has announced an investment of nearly $11 million in five projects for research to combat Huanglongbing (HLB), commonly known as citrus greening disease.

HLB, caused by an insect bacterium, is the most severe threat to global citrus production, the USDA said.

 “NIFA’s Emergency Citrus Disease Research and Extension program brings the nation's top scientists together with citrus industry representatives to find scientifically sound solutions to combat and prevent HLB at the farm-level,” said NIFA Director Dr. Carrie Castille.

“This year’s awards represent all three major U.S. citrus growing regions and include possible solutions ranging from blocking HLB transmission from inside the insect vector to utilizing novel anti-microbial peptides to treat HLB-infected trees.”
 
The fiscal year 2021 five funded Emergency Citrus Disease Research and Extension projects include:

• Texas A&M AgriLife Research will leverage public-private partnerships between state agencies, universities, USDA’s Agricultural Research Service, and the citrus industry to pursue advanced testing and commercialization of promising HLB therapies and extend outcomes to stakeholders. ($7,000,000)
• University of California, Riverside will build on previous work and evaluate the performance of 300 hybrid citrus trees in established trials to map HLB tolerance/resistance genes and release superior new rootstocks. ($1,499,998)
• University of Florida seeks to develop a bacterial pathogen transmission blocking strategy (specifically to block Candidatus Liberibacter asiaticus, the pathogen that causes HLB) toward mitigation of citrus greening-related losses in an integrated pest management framework. ($1,020,810)
• University of Florida’s project will support the needs of both commercial and residential citrus growers by comparing new tools to support young trees and develop management recommendations for the incorporation of each tool into production and residential settings. ($750,000)
• University of Florida aims to introduce and transfer the natural HLB resistance present in Australian limes into conventional citrus to produce HLB-resistant Australian lime hybrid rootstocks and deploy these hybrids to protect susceptible citrus scions against HLB. ($500,000)

HLB is considered the most destructive disease in citrus growing regions worldwide and has become the greatest challenge for the U.S. citrus industry. Currently, HLB has no cure.

Since HLB’s initial U.S. detection in 2005, citrus acreage and production in Florida has decreased by 60 percent and 80 percent, respectively. The disease has spread to all citrus-producing states, including Texas and California.

Although citrus greening is a serious threat to the citrus industry worldwide, significant progress has been made to coordinate a multipronged approach for citrus greening management and suppression of the Asian citrus psyllid, an insect that carries and spreads HLB.