Skip to main content
Hero Image
citrus leaf with yellow spots

Share

Citrus Greening Portal

What is Huanglongbing or Citrus Greening?

Huanglongbing (HLB), also known as citrus greening, poses the most serious threat that the Florida citrus industry has ever faced. The bacteria that cause citrus greening - three species of Liberibacter – most likely originated in Asia prior to 1900 and has slowly spread throughout the world in many citrus growing areas. In countries where the disease is endemic, different varieties of citrus trees like “sweet orange” begin to decline within 3-4 years after planting, resulting in reduced fruit crop and fruit quality. 

Citrus greening FAQs

Citrus greening was first detected in Florida in 2005. By 2008, it had been identified in most of the citrus growing counties in the state. Despite intense efforts, citrus greening now threatens the survival of Florida citrus, has a toehold in other citrus areas, and poses a threat to the entire U.S. citrus industry. 

What are we doing to control citrus greening?

ARS scientists across the country are actively engaged in research with university and industry partners on all aspects of this disease problem, including the host, pathogen, and insect vector. We are making great progress in not only understanding how citrus greening infiltrates healthy citrus trees, but how to protect these trees from the disease. Our goal is to overcome citrus greening and ensure the U.S. citrus industry can provide consumers with tasty, high quality citrus fruits for years to come.

 

Watch our citrus greening research in action:

Scientists’ Push for HLB-Tolerant Citrus

Genetic discovery could speed the search for hybrid citrus trees that tolerate citrus greening disease and produce fruit ideal for making juice.

How to Save the Florida Citrus Industry?

ARS researchers find answers in the unique biology of the ocean.

 

Citrus Greening: Is the End in Sight?

Researchers are boosting the citrus tree immune system.

 

ARS Citrus Rootstocks: A Success Story

 Begun by USDA more than a century ago, the citrus research program has helped to ensure a bounty of oranges and other citrus. 

 

A dog detecting citrus greening in a grove
Canines Detect Citrus Greening

Specially trained canines may be used to detect citrus greening in orchards.

 

Jekyll from Hyde in Citrus Disease

Researchers found a way to distinguish between two citrus diseases that are similar in appearance, but dangerously different.

 

citrus leaf with yellow spots
Guarding Against Citrus Greening

Researchers are developing new strategies to combat citrus greening, including an improved diagnostic test to detect the bacterium.

 

See Where We Are Conducting Citrus Greening Research 

Citrus and Other Subtropical Products Research Unit: Fort Pierce, FL    

Subtropical Plant Pathology Research Unit: Fort Pierce, FL  

Subtropical Insects and Horticulture Research Unit: Fort Pierce, FL 

Emerging Pests and Pathogens Research Unit: Ithaca, NY

National Clonal Germplasm Repository for Citrus: Riverside, CA

Molecular Plant Pathology Laboratory: Beltsville, MD


 


For more information about ARS citrus greening research, contact:

Tim Rinehart 
Crop Production and Protection
National Program Leader (Specialty Crops)
Email: tim.rinehart@usda.gov

Jack Okamuro
Crop Production and Protection (Biotechnology)
National Program Leader
Email: jack.okamuro@usda.gov 


 


Additional Citrus Greening Resources: 

Coordinated Response to Citrus Greening Disease | USDA

Citrus Greening | Animal and Plant Health Inspection Service

Huanglongbing/Citrus Greening Disease Information | Florida Department of Agriculture and Consumer Services

Citrus Greening | National Invasive Species Information Center