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Citrus Greening

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Citrus greening, also called Huanglongbing (HLB), is a bacterial infection of citrus

plants. It is one of the most serious citrus diseases in the world. Once infected, most

trees die within a few years. There is no cure. While the disease poses no health

threat to people or animals, it has devastated millions of acres of citrus crops

throughout the United States and abroad.
In the United States, citrus greening is spread by a tiny insect called the Asian citrus

psyllid (Diaphorina citri Kuwayama). Infected trees produce fruits that are poorly

colored, possibly lopsided, and bitter. This fruit can only be sold for juicing. Citrus

greening is currently found throughout Georgia, Florida, Puerto Rico, and the U.S.

Virgin Islands. It is also found in portions of Alabama, California, Louisiana, South

Carolina, and Texas.

What To Look For

While the Asian citrus psyllid causes little damage when it feeds, it spreads citrus

greening disease which gradually kills fruit-bearing trees, including oranges, lemons,

limes, tangerines, and grapefruits.

Here's what to look for:

Asian citrus psyllid

Eggs are yellow-orange and almond-shaped. They are often tucked inside

crevices and leaf folds.

Nymphs are difficult to see, but leave behind waxy, white excretions on

plants.

Adult psyllids are gnat-sized, only about 1/8-inch long. When approached,

they jump or fly.

Adults have three abdominal colors: blue-green, gray-brown, or orangeyellow.

They have mottled brown wings, and the last two segments of their

antennae are black.

Citrus greening

Once infected, a tree can remain asymptomatic, serving as a source of

bacteria that infects other trees.

Over time, an infected tree will start producing fewer fruit that are partially

green, smaller, shaped irregularly, and taste bitter. Leaves may show

asymmetrical, blotchy mottling.

Citrus greening is present in most citrus-growing States except Arizona.

View images of Asian citrus psyllid and citrus greening.
How To Prevent This Disease

To help prevent this pest from spreading, here's what you can do:

Know the quarantines in your area.

Buy only USDA-certified citrus plants.

Don't move branches, green waste, dead trees, or other regulated items out of

a quarantined area.

Don't mail or transport home-grown citrus fruit or plants out of a quarantined

area.

Commercial nurseries must follow strict protocols for moving citrus nursery

stock out of quarantined areas.

How It Is Treated

There is no treatment or cure for citrus greening. Infected trees eventually die.

Report Signs of Citrus Disease

If you think you've seen signs of this disease or pest, immediately report it by

completing our online form.

Report Form (English)

Report Form (Spanish)

Controlling Citrus Greening and Asian Citrus

Psyllid

Current Status

APHIS publishes the legal description of current quarantine areas. Users can search

by State and pest to determine quarantine area(s).

Table of Federal Quarantine Descriptions

Interactive Citrus Federal Quarantine Map
Regulatory Information

Interstate Movement of Regulated Fruit from a Quarantine Area (7 CFR 301.76)

Regulated Articles Table: Use this table to find requirements for moving

regulated articles, such as fruit, nursery stock, and other items.

View the National Environmental Policy Act (NEPA) Documents in the Reports

and Assessments section below.

Huanglongbing Multi-Agency Coordination

In 2013, the U.S. Department of Agriculture implemented a unified emergency

response framework to help address the citrus industry’s immediate and long-term

needs in dealing with citrus greening. APHIS leads the group, which includes

representatives from USDA’s Agricultural Research Service (ARS) and National

Institute of Food and Agriculture (NIFA); the U.S. Environmental Protection Agency;

State departments of agriculture in Arizona, California, Florida, and Texas; and citrus

industry organizations in California, Florida, and Texas. The multi-agency group

helps to coordinate and prioritize Federally funded research with industry's efforts to

bridge the gap between research and implementation, reduce unnecessary

duplication, and more quickly provide practical tools for citrus growers to use.

Learn more about the coordinated response to citrus disease

Potentially Actionable Suspect Sample Policy

A potentially actionable suspect sample (PASS) is a regulatory sample3  from the

environment or an APHIS-approved exclusionary facility5  where preliminary

diagnostics indicate that Candidatus Liberibacter asiaticus, a USDA-regulated

pathogen, is present and must be confirmed by APHIS' Plant Pathogen Confirmatory

Diagnostics Laboratory (PPCDL).

Samples Collected from a Non-Regulated Area

Any regulatory sample collected from a non-regulated area1  or APHISapproved exclusionary facility that tests positive using APHIS-approved tests for

the presence of Candidatus Liberibacter asiaticus by a NPPLAP-accredited lab6

using an APHIS-approved screening test is considered a PASS and must be

forwarded to PPCDL for final determination. A sample4  should consist of
symptomatic plant material.

Sample Diagnostics

USDA APHIS PPQ Science & Technology

Plant Pathogen Confirmatory Diagnostics Laboratory

9901 Powder Mill Rd. Bldg. 580

Laurel, MD 20708

Phone: (301) 313-9208 or (301) 313-9271

When forwarding materials, notify the lab by email (APHISPPQCPHSTBeltsvilleSampleDiagnostics@usda.gov). Include the number of samples,

screening diagnostic results, and tracking information in this communication. Do not

ship samples on Fridays or the day before a federal holiday.

Please see additional information for preparing and submitting samples.

Samples Collected from a Regulated Area

A regulatory sample collected in a regulated area2 where preliminary

diagnostics indicate Candidatus Liberibacter asiaticus by a NPPLAP-accredited lab

using the APHIS-approved screening test is considered a PASS and must be

forwarded to PPCDL ONLY under the following conditions:

The sample is an unusual detection (novel symptoms or new host), and/or

The sample will result in the expansion of a previously established regulated

area

A NPPLAP-certified analyst at a NPPLAP-accredited laboratory is authorized to

make the final determination on a regulatory sample collected from a regulated area

(previously confirmed positive by APHIS) if the laboratory notifies the APHIS national

or regional program manager of the positive within 24 hours of the diagnostic result.

Definitions

1 Non-Regulated Area: Any area where citrus canker is not known to occur in the

United States.

2 Regulated Area: Any APHIS-recognized area where citrus

greening/huanglongbing has been federally confirmed.
3 Regulatory Sample: This is a sample of regulatory concern to APHIS for citrus

greening/huanglongbing collected by regulatory officials.

4 Sample: A sample refers to a single bag of leaves or a twig with attached leaves.

Each sample is to contain a minimum of 12 symptomatic (unhealthy) leaves; 12-16

leaves if possible. It is strongly encouraged that each sample is from one plant.

5 APHIS-approved exclusionary facility: A greenhouse structure designed to

exclude quarantine pests that is approved by APHIS to produce citrus nursey stock

for interstate movement.

6 NPPLAP-Accredited Lab: A laboratory recognized by APHIS through the National

Plant Protection Laboratory Accreditation Program (NPPLAP) as possessing all the

necessary equipment and certified personnel to perform citrus greening screening

tests using current APHIS work instructions.

Spread the Word

Save Our Citrus Videos

Save Our Citrus: Put the Squeeze on Citrus Disease (Spanish)

Save Our Citrus: Put the Squeeze on Citrus Disease - Arizona

Save Our Citrus: Put the Squeeze on Citrus Disease - California

Save Our Citrus: Put the Squeeze on Citrus Disease - Florida

Save Our Citrus: Put the Squeeze on Citrus Disease - Louisiana

Save Our Citrus: Put the Squeeze on Citrus Disease - Texas

Reports and Assessments

October 2014 - Field Release of the Parasitoid Diaphorencyrtus aligarhensis for

the Biological Control of the Asian Citrus Psyllid in the Contiguous United States

August 2010 - Asian Citrus Psyllid Control Program in the Continental United

States and Puerto Rico, Environmental Assessment

Finding of No Significant Impact For Asian Citrus Psyllid Control Program in

the Continental United States and Puerto Rico Environmental Assessment

June 2010 - Proposed Release of a Parasitoid ( Tamarixia radiata Waterston) for

the Biological Control of Asian Citrus Psyllid ( Diaphorina citri Kuwayama) in the

Continental United States, Environmental Assessment
July 2009 - Quarantine and Interstate Movement of Citrus Greening and Asian

Citrus Psyllid, Environmental Assessment

Revised Finding of No Significant Impact for Quarantine and Interstate

Movement of Citrus Greening and Asian Citrus Psyllid, Environmental

Assessment

Finding of No Significant Impact For Asian Citrus Psyllid Control Program in

the Continental United States and Puerto Rico Environmental Assessment

January 2009 - Asian Citrus Psyllid Control Research Project, Hidalgo County,

Texas, Environmental Assessment

Calendar Year 2010 Amendment to Finding of No Significant Impact for

Asian Citrus Psyllid Control Research Project, Hidalgo County, Texas

Finding of No Significant Impact for Asian Citrus Psyllid Control Research

Project, Hidalgo County, Texas, Environmental Assessment

October 2007 - Movement of Regulated Articles From Citrus Greening and Asian

Citrus Psyllid Quarantine Zones, Environmental Assessment

Finding of No Significant Impact for Movement of Regulated Articles from

Citrus Greening and Asian Citrus Psyllid Quarantine Zones, Environmental

Assessment

January 2006 - Citrus Greening Control Program in Florida Nurseries,

Environmental Assessment

Finding of No Significant Impact Citrus Greening Control Program in Florida

Nurseries Environmental Assessment