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Publication #CH198

 

Citrus Greening: A Serious Threat to the Florida Citrus Industry1

J.D. Yates, T.M. Spann, M.E. Rogers, and M.M. Dewdney2

This publication was designed as a trifold brochure. Click here to view in brochure format (pdf, 375 KB)

Greening History

  • The vector, Asian citrus psyllid, was first found in Florida in 1998.

  • Citrus greening disease was first detected in south Florida in August 2005.

  • As of October 2006, greening infected trees had been found in 12 counties.

  • By October 2007, infected trees had been discovered in 28 counties

  • Symptoms can be found year round, but are more prominent September through March.

Figure 1. 

Counties in dark blue have confirmed greening finds as of July 2008


[Click thumbnail to enlarge.]

Greening Vector

  • Asian citrus psyllid (Diaphorina citri)

Figure 2. 
[Click thumbnail to enlarge.]

  • Five nymphal stages

  • Numerous generations per year

  • Egg to adult in 2 weeks at 75° - 85° F

  • The egg stage lasts an average of 3 - 4 days

  • The duration of the nymphal stages is about 12 - 14 days at 82° F

Figure 3. 

  • Adult psyllids may live for several months

  • Psyllids can acquire the greening pathogen from infected trees, regardless of whether symptoms are present on the tree

Figure 4. 

  • The longer psyllids remain uncontrolled and allowed to feed on infected trees, the higher the chance that those psyllids will become capable of acquiring and spreading greening to other trees.

Figure 5. 

  • Psyllid populations are best managed by controlling adults prior to the presence of new flush, which facilitates rapid population growth.

Figure 6. 

  • Chemical control of the psyllid and removal of infected trees are the only methods currently available to manage the spread of greening disease.

Greening Symptoms

Vein corking

Figure 7. 

Fruit remain green at the blossom end

Figure 8. 

Yellow shoots

Figure 9. 

Yellow veins

Figure 10. 

Reduced fruit size

Figure 11. 

Blotchy mottle - key diagnostic symptom

Figure 12. 

Greening Management

  • Restrict propagation and movement of Murraya paniculata and Severinia buxifolia, plants known to harbor the bacterium.

  • Scout routinely (a minimum of 4 times each year).

  • Remove infected trees.

  • Integrated pest management.

  • Use disease-free nursery trees.

  • Reduce inoculums through frequent disease surveys and removal of symptomatic trees.

• Suppress Asian citrus psyllid populations through chemical, biological and cultural controls.

Diagnostics

  • PCR (Polymerase Chain Reaction) is the only way to positively identify citrus greening.

  • Three testing sites are available:

  • Southern Gardens Diagnostic Laboratory, 111 Ponce de Leon Ave., Clewiston, FL, 33440, (863) 902-2249

  • UF/IFAS Southwest Florida Research and Education Center, 2686 SR 29 N., Immokalee, FL, 34142, (239) 658-3400, http://swfrec.ifas.ufl.edu/hlb/

  • Florida Division of Plant Industry, 1-800-282-5153

Resources

  • Citrus Research and Education Center website: www.crec.ifas.ufl.edu

  • Greening Symptoms Laminated Sheet

  • Greening Symptoms versus Nutritional Deficiencies Laminated Sheet

  • Greening Symptoms versus Blight and Tristeza Laminated Sheet

  • Greening Field ID Pocket Guide

  • Greening Training DVD

  • Greening Screensaver

  • 2008 Florida Citrus Pest Management Guide

Contacts

Citrus Research and Education Center

Jamie Yates
Canker and Greening Extension Education
863-956-1151 ext. 1302
* * *
Michael Rogers, Ph.D.
Entomologist
863-956-1151 ext. 1224
* * *
Ron Brlansky, Ph.D.
Plant Pathologist
863-956-1151 ext. 1300
* * *
Megan Dewdney, Ph.D.
Plant Pathologist
863-956-1151 ext. 1417

Citrus Extension Agents

Ryan Atwood
Marion, Lake, Volusia,
Orange, Seminole, Brevard
and Osceola counties
352-343-4101
* * *
Gary England
Citrus, Hernando, Sumter
and Pasco counties
352-793-2728
* * *
Steve Futch, Ph.D.
DeSoto, Hardee, Manatee
and Sarasota counties
863-956-1151
* * *
Tim Gaver
St. Lucie, Martin
Okeechobee and
Indian River counties
772-462-1600
* * *
Tim Hurner
Highlands County
863-402-6540
* * *
Chris Oswalt
Polk and Hillsborough counties
863-519-8677
* * *
Mongi Zekri, Ph.D.
Hendry, Glades, Lee, Charlotte
and Collier counties
863-674-4092

Figure 13. 

Footnotes

1.

This document is CH198, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date, July 2008. Revised July 2009. Visit the EDIS Website at http://edis.ifas.ufl.edu.

2.

J.D. Yates, assistant coordinator for canker and greening extension education, T.M. Spann, assistant professor, Horticultural Sciences Department, M.M Dewdney, assistant professor, Plant Pathology Department, Citrus Research and Education Center, Lake Alfred, FL, 33850, Institute of Food and Agricultural Sciences, University of Florida.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, Dean.