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Citrus Greening

Scientific Name

Candidatus Liberibacter asiaticus

Common Name

Citrus greening, Huanglongbing (HLB), yellow shoot disease, yellow dragon disease

Native To
Date of U.S. Introduction

The vector, Diaphorina citri (Asian citrus psyllid), was first discovered in Florida in 1998; the disease was first discovered in Florida in 2005; Louisiana in 2008; South Carolina and Georgia in 2009; California and Texas in 2012 (Michaud 2004; Wang and Trivedi 2013)

Means of Introduction

Possibly through illegally imported plant material (Michaud 2004)


Bacterial disease that infects citrus trees, where it shortens the lifespan of trees and reduces fruit yield and quality (Wang and Trivedi 2013)

Citrus greening
Image use policy

Citrus greening symptoms (brown necrotic or aborted seeds in infected mandarin)


Photo by J.M. Bové; INRA Centre de Recherches de Bordeaux, France

Find more images


  • ARS Research News - New Discovery Speeds Scientists’ Push for HLB-Tolerant Citrus

    • Feb 28, 2024
    • USDA. Agricultural Research Service.

    • A genetic discovery by ARS and University of Florida scientists could speed the search for hybrid citrus trees that tolerate citrus greening disease (Huanglongbing) and produce orange-like fruit ideal for making juice.

  • Could Camels Be the Key to Fighting Citrus Greening Disease and Other Pathogens?

    • Aug 14, 2023
    • USDA. ARS. Tellus.

    • Researchers have been working on a solution to fight citrus greening disease and may have found one in the unique antibodies found in camels, llamas, and alpacas.

  • How to Save the Florida Citrus Industry?

    • Apr 24, 2023
    • USDA. ARS. Tellus.

    • Imagine a devastating plant disease that sweeps the land, decimating crops. For Florida’s citrus growers, that apocalyptic vision is not a horror movie, but a reality: since it was first identified in the Sunshine State in 2005, citrus greening disease has reduced Florida’s citrus production by a whopping 70%. Without any treatment or cure available, desperate growers have cut down infected trees or abandoned their groves entirely. Scientists have been racing to come up with a solution. Now, an ARS research team believes it may have one, in the form of: stingrays.

  • USDA Asks for Help Protecting Citrus in the Lower Rio Grande Valley

    • Jun 10, 2022
    • USDA. Animal and Plant Health Inspection Service.

    • The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) needs your help safeguarding Texas citrus from invasive citrus pests and diseases currently threatening livelihoods and agricultural production in the Lower Rio Grande Valley. APHIS employees in Cameron, Hidalgo, Willacy and Zapata counties are working with the Texas Department of Agriculture (TDA) to inspect and survey fruit trees in residential yards and commercial properties for signs of invasive fruit flies and citrus diseases, such as citrus canker and citrus greening. These pests and diseases, if allowed to become established or spread, could devastate grapefruit, sweet and sour orange, key lime, sweet lemon, and other types of fruit production in that area.

  • APHIS Establishes Citrus Greening (Huanglongbing) Quarantines in Alabama

    • Dec 8, 2021
    • USDA. Animal and Plant Health Inspection Service.

    • Effective immediately, the USDA's Animal and Plant Health Inspection Service (APHIS), in cooperation with the Alabama Department of Agriculture and Industries (ADAI), is establishing quarantines for Huanglongbing (HLB; citrus greening), caused by Candidatus Liberibacter asiaticus, in all of Baldwin and Mobile Counties in Alabama. APHIS is taking this action because of HLB detections in plant tissue samples collected in multiple locations in Alabama.

      APHIS is applying safeguarding measures on the interstate movement of regulated articles from the quarantined counties in Alabama. These measures parallel the intrastate quarantine that ADAI established on June 2, 2020. This action is necessary to prevent the spread of HLB to non-infested areas of the United States.

  • Asian Citrus Greening Disease: The Threat to Africa’s Citrus Trade

    • Oct 11, 2021
    • CAB International. Invasives Blog.

    • The yield losses attributed to Asian citrus greening disease once established can be devastating. If the disease continues to spread unabated in the citrus growing regions of East Africa, the annual value of lost production could potentially reach up to US $127 million over the next ten to 15 years, according to a recent paper published by CABI. The paper, The Asian Citrus Greening Disease (Huanglongbing): Evidence Note on Invasiveness and Potential Economic Impacts for East Africa (Jun 2021) [PDF, 2.9 MB], provides a review of the global literature on Asian citrus disease or huanglongbing (HLB) and estimates its potential economic impact on East Africa. The paper also makes recommendations for biosecurity preparedness, surveillance and management options to help decision-makers and citrus growers.

  • Citrus Greening Portal

    • USDA. ARS. AgLab.

    • Huanglongbing, also known as citrus greening, poses the most serious threat that the Florida citrus industry has ever faced. 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. 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.

  • Coordinated Response to Citrus Greening Disease

    • U.S. Department of Agriculture.

    • USDA established a unified emergency response framework to address Huanglongbing (HLB), a serious disease of citrus that affects several U.S. states and territories. This framework will allow USDA and its many partners to better coordinate HLB resources, share information and develop operational strategies to maximize effectiveness.

  • You Can Help Prevent Citrus Disease - Story Map

    • USDA. Animal and Plant Health Inspection Service.

    • See also: APHIS in Action to explore plant and animal health or wildlife damage management data and Interactive Story Maps

Distribution / Maps / Survey Status


Federally Regulated

  • Citrus Diseases - Federal Quarantines

    • USDA. APHIS. Plant Protection and Quarantine.

    • Contains the legal description of current federal quarantine areas for several citrus pests and diseases (Asian citrus pysllid, citrus black spot,  citrus canker, citrus greening, sweet orange scab),  Users can search by state and pest to determine the quarantine area(s) by state and territories.

  • Citrus Federal Quarantine Boundary Viewer

    • USDA. Animal and Plant Health Inspection Service.

    • Select layer to view quarantine by species (Asian citrus psyllid, citrus black spot, citrus canker,  citrus greening, sweet orange scab).
      See also: APHIS in Action to explore plant and animal health or wildlife damage management data and Interactive Story Maps

  • Citrus Regulated Articles

    • USDA. APHIS. Plant Protection and Quarantine.

    • Contains the requirements for moving fruit, nursery stock, or other regulated articles for several citrus pests and diseases.

  • Domestic Quarantine Notices (Title 7: Agriculture, Part 301) - Citrus Greening and Asian Citrus Psyllid

    • U.S. Government Printing Office. Electronic Code of Federal Regulations.

  • Hungry Pests - Pest Tracker

    • USDA. Animal and Plant Health Inspection Service.

    • See what states have a federal quarantine for any of the targeted Hungry Pests, and identify which pests or diseases are at greatest risk due to a suitable habitat. In addition to federal quarantines, state-level quarantines might apply see State Summaries of Plant Protection Laws and Regulations (National Plant Board).

      See also: The Threat for an overview of the top invasive pest threats; indicates places with Federal Quarantines in place.

  • Import Federal Orders

    • USDA. APHIS. Plant Protection and Quarantine.

    • A Federal Order is a legal document issued in response to an emergency when the Administrator of APHIS considers it necessary to take regulatory action to protect agriculture or prevent the entry and establishment into the United States of a pest or disease. Federal Orders are effective immediately and contain the specific regulatory requirements.


Selected Resources

The section below contains highly relevant resources for this species, organized by source.

Federal Government
International Government
State and Local Government