Lethal Bronzing Disease

A new palm phytoplasma in Florida

Photo: Monica Elliott, University of Florida, Bugwood.org, #5475315

Lethal Bronzing Disease was previously known as Texas Phoenix Palm Decline. The name was changed recently to reflect the broader range of host species and one of the main symptoms of this disease. Lethal Bronzing disease is also referred to as Date Palm Lethal Decline.

1 Lethal Bronzing Disease (LBD)

Phoenix sp. decline due to LBD

Photos: N. Harrison, University of Florida

Lethal Bronzing Disease (LBD) is a palm disease caused by a phytoplasma, a specialized unculturable bacterium without a cell wall.

In Florida, LBD first detected in 2006 on a Phoenix species located in Hillsborough county (Tampa area). Before the detection of LBD, the only palm disease in Florida caused by a phytoplasma was lethal yellowing, a systemic palm disease that is transmitted by a common neotropical ( crudus). The symptoms of lethal yellowing are almost identical to LBD, but the host range and geographical distribution differ. While the phytoplasmas that cause lethal yellowing and LBD are similar they are genetically distinct from each other.

2 Geographic Distribution

Lethal Bronzing detected

LBD has also been detected in parts of Mexico

Map based on information from Bahder (2019). Created using: mapchart.net

LBD was first detected in Texas in 2001 in the southern coastal area on Canary Island date palm (Phoenix canariensis). Giving rise to the original name of this diseas, Texas Phoenix Palm Decline. As of 2020, LBD has been found in parts of Texas, Louisiana, Florida and Mexico. In Texas, the disease has been detected in the following counties: Bexar, Cameron, Hidalgo, Kleberg, Nueces and Willacy.

3 Distribution in Florida

Lethal Bronzing detected

Map based on information from Bahder (2019) and Halbert et al. (2018) . Created using: mapchart.net

Since it was first detected in Florida in 2006, LBD has spread to 34 counties through out the state. The disease has been detected in a variety of settings including landscapes, nurseries and natural areas. While unknown as to how it spread to Florida, it may have spread via infected plant material or an infected vector.

4 Host Plants

Coconut palm Bismarck palm Chinese Fan palm Cocos nucifera Bismarckia nobilis Livistona chinensis

Photos: T. K. Broschat, University of Florida

Although originally discovered in the phoenix species LBD can affect a variety of different palms including: Coconut palm, Bismark Palm Chinese Fan Palm among others. Host Range: Scientific name Common name Adonidia merrillii Christmas Palm Bismarckia nobilis Bismarck Palm Butia capitata Pindo Palm Carpentaria acuminata Carpentaria Palm Cocos nucifera Coconut Palm Livistona chinensis Chinese Fan Palm Phoenix canariensis Canary Island Date Palm Phoenix dactylifera Edible Date Palm Phoenix roebelinii Pygmy Date Palm Phoenix sylvestris Wild Date Palm Pritchardia pacifica Fiji Fan Palm Pseudophoenix sargentii Buccaneer Palm Sabal Mexicana Mexican Palmetto Sabal palmetto Cabbage Palm Syagrus romanzoffiana Queen Palm Trachycarpus fortunei Chinese Windmill Palm

5 Symptomatic Host Plants

Canary Island Date Palm Edible Date Palm Wild Date Palm Cabbage Palm Phoenix canariensis Phoenix dactylifera Phoenix sylvestris Sabal palmetto

Photos: N. Harrison and M. Elliott, University of Florida

Symptoms present similarly though out the host range with discoloration or necrotic canopy and spear leaf collapse as main symptoms.

Host Range: Scientific name Common name Adonidia merrillii Christmas Palm Bismarckia nobilis Bismarck Palm Butia capitata Pindo Palm Carpentaria acuminata Carpentaria Palm Cocos nucifera Coconut Palm Livistona chinensis Chinese Fan Palm Phoenix canariensis Canary Island Date Palm Phoenix dactylifera Edible Date Palm Phoenix roebelinii Pygmy Date Palm Phoenix sylvestris Wild Date Palm Pritchardia pacifica Fiji Fan Palm Pseudophoenix sargentii Buccaneer Palm Sabal Mexicana Mexican Palmetto Sabal palmetto Cabbage Palm Syagrus romanzoffiana Queen Palm Trachycarpus fortunei Chinese Windmill Palm

6 Early Symptoms Symptoms on Phoenix sylvestris

Discoloration of the leaf tips Sudden loss of fruit

Dead inflorescence (flowers) Photos: N. Harrison and M. Elliott, University of Florida

The symptoms of LBD are almost the same as those of lethal yellowing on Phoenix spp.; however, root decay is an additional symptom that has been observed in LBD.

Early symptoms of LBD include: a premature drop of most fruits, death of inflorescences, and discoloration of leaf tips.

These symptoms may occur for all trees. The premature drop of fruits and inflorescence necrosis will be only observed in mature palms that can produce fruits and be in the fruit producing season.

Discoloration of the foliage begins at the tips of leaves on the oldest, lowermost leaves. The old leaves quickly turn to a reddish-brown, dark brown or gray color. This leaf discoloration can be confused with some other issues such as natural senescence or nutrient deficiency. This symptom may not be obvious when dying and dead leaves are regularly removed in nursery and landscape settings. Consequently, it is important to monitor the trees closely to recognize the onset of leaf discoloration.

7 Later Symptoms Symptoms on Phoenix sylvestris

Dead spear leaf Dead spear leaf hanging down from the canopy

Photos: N. Harrison and M. Elliott, University of Florida

As the disease progresses the older leaves will become discolored and necrotic, eventually the spear leaf will also collapse and die. The spear leaf is the vertical and unopened newest leaf of the palm (yellow arrows). The death of the spear leaf occurs in Phoenix palms when less than 1/3 of the leaves have become discolored; in Sabal palm, it occurs when approximately 2/3 of the leaves have become discolored.

The spear leaf usually collapses 2-3 months after the first appearance of symptoms, however this is highly variable and is also affected by species.

Once the spear leaf is dead, the tree is dead, no new leaves develop, and discoloration or necrosis of the remaining leaves will continue from the oldest to the youngest leaves. It is important to make sure the spear leaf itself is in fact dead, as there are many leaves that surround the spear leaf that can remain green for a long period after the collapse of the spear leaf. It is also possible for there to be no dead leaves in the canopy, but the spear leaf be collapsed. It is also easy to confuse the brown sheath around the spear leaf for a dead spear leaf (in Canary Island date palms, the spear leaf is often enclosed in a thin, brown sheath that looks like paper).

8 Vector of LBD • • (formerly Myndus crudus) • American palm cixiid • Native to Florida • Found through out the southern US and the Caribbean

Photos: Left- N.A. Harrison, cabi.org; Right- J.D. de Filippis, University of Florida, www.bugwood.org, #0725076.

The phytoplasma that causes LBD is an unculturable bacterium without a cell wall that is found in the phloem of its host plants. The disease is transmitted by piercing-sucking vectors that feed in the phloem tissues and cannot survive outside the host plant or the insect vector.

This pathogenic phytoplasma can be transmitted by an insect vector, Haplaxius crudus also called the American Palm Cixiid. Haplaxius crudus is a planthopper in the family . H. crudus is found through out the Southeastern US, as far north as South Carolina and west to Texas. It also can be found through out the Caribbean.

Immature life stages live and feed in the thatch layer of grass (the layer of dead and lving organic matter that accumulates), however the adults feed on the exclusively on foliage of palms where they can transmit LBD. .

9 Monitoring and Management

• Actively monitor for symptoms • Remove infected palms • Preventative antibiotic injections (Oxytetracycline HCl) • Use of host resistance for long-term solution • Plant resistant palm trees • Diversify the landscape

Photo: B. Bader, University of Florida

In LBD active areas, susceptible hosts should be monitored regularly for typical symptoms. Palms with a suspected infection should be removed as quickly as possible to limit the spreading of this disease. Palms in the area of the infected tree should be injected with Oxytetracycline HCl every tree to four months as a preventative measure. This antibiotic is effective for prevention, however after infection the antibiotic does not cause symptom reversal.

Please report suspect infections to your local county agent of your Department of Agriculture. As the diagnosis of this disease must be done in a plant pathology lab, your local county agent or plant inspector can provide instructions on how to obtain a sample and send it to an appropriate laboratory.

It should be noted that there are Sabal palms still alive and asymptomatic in the Tampa area after several years of infestation. While more research must be conducted in this area, it is a possibility these palms may carry a natural resistance to the phytoplasma.

Research is ongoing into how to sustainably manage this disease, including management of the vector H. crudus.

10 Reporting a Pest in Florida

UF/IFAS Faculty • Local county extension office – https://sfyl.ifas.ufl.edu/find-your-local-office/ • Insect ID Lab- Dr. Lyle Buss – http://entnemdept.ufl.edu/insectid/ • UF/IFAS Plant Diagnostic Center- Dr. Carrie Harmon – https://plantpath.ifas.ufl.edu/extension/plant-diagnostic-center/

The UF/IFAS faculty is responsible for reporting diseases, , weeds, nematodes, or any other invasive species to the Florida Department Agriculture and Consumer Services, Division of Plant Industry (FDACS, DPI). Reporting this information is essential to protect Florida agriculture, communities and natural areas.

Local county extension agents can assist in identifying plant pest or assist in submitting a pest sample to the correct department or agency for identification. Attached is a link to find the closest extension agent near you.

If you need a insect identified, Dr. Lyle Buss at is the director of the Insect ID Lab at the University of Florida. The link attached will direct you to the insect ID Lab for further instructions for contact, questions, and submission forms.

If a diseased plant needs identification, the link to the UF/IFAS Plant Diagnostic Center run by Dr. Carrie Harmon is attached to assist in reporting and identifying the correct pest.

The diagnosticians and identifiers in each area will also provide management strategies for the pest identified to help eliminate the damage caused on the plants. If an invasive pest is found, they will send it FDACS, DPI for further testing.

11 Reporting Distance Diagnostic and Identification System

• Digital Diagnostic Collaboration – Extension agents – Laboratories – Clinics – Specialists • https://ddis.ifas.ufl.edu/

The DDIS system connects the UF/IFAS faculty mentioned before to provide quick and accurate identification throughout Florida. This reporting collaboration tool enhances screening, early detection, monitoring, pest mapping, and rapid communication to protect agriculture. The site provides training, media of pest, equipment, and diagnostic labs in Florida.

12 Reporting FDACS: Division of Plant Industry • FDACS, DPI Responsibility oAnnouncing detection or establishment of new invasive species. oReporting is a legal obligation under Florida Statute 581.091. • Submission Form – http://forms.freshfromflorida.com/08400.pdf – https://www.fdacs.gov/Agriculture-Industry/Pests-and-Diseases/How-to- Submit-a-Sample-for-Identification

Florida Department of Agriculture and Consumer Services: Division of Plant Industry is a regulatory agency that detects, intercepts, and controls Florida’s native and commercially grown plants. Announcing the establishment of new invasive species can affect Florida’s agricultural producers and trade of agricultural products.

FDACS, DPI provides online submission forms to fill out and send into the agency for proper identification. Additionally, DPI provides useful videos of how to properly handle the specimens before shipping them for identification

13 FDACS, DPI Contact • Dr. Leroy Whilby, Bureau Chief-Entomology, Nematology and Plant Pathology – 352-395-4661 – [email protected]

• Dr. Paul Skelley, Assistant Chief-Entomology, Nematology and Plant Pathology – 352-395-4678 – [email protected]

• Division of Plant Industry Hotline • 1-888-397-1517 • [email protected]

The DPI contacts provided will assist in determining the next steps if the pest found is of regulatory concern. Additionally, FDACS, DPI has a hotline with both a phone number and email for questions and concerns.

14 Original Authors

• Nigel Harrison, Ph.D. – Associate Professor, Fort Lauderdale Research and Education Center, University of Florida • Keumchul Shin, D.P.M. – Former Doctor of Plant Medicine Program Graduate Research Assistant, University of Florida • Amanda Hodges, PhD – Associate Extension Scientist, Entomology and Nematology Department, University of Florida

15 Revision Authors

• Shannon McAmis, M.S. – Graduate Research Assistant, Doctor of Plant Medicine Program, University of Florida • Amanda Hodges, PhD – Associate Extension Scientist, Entomology and Nematology Department, University of Florida

16 Original Editors

• Stephanie Stocks, M.S. – Former Department of Entomology and Nematology, University of Florida • Matthew D. Smith, Ph.D. – Former Postdoctoral Associate, Department of Entomology and Nematology, University of Florida

17 Original Reviewers • Susan Halbert, Ph.D – Florida Department of Agriculture and Consumer Services, Division of Plant Industry • Andrew Derksen, M.S. – Former Pest Survey Scientist, Florida Department of Agriculture and Consumer Services, Division of Plant Industry • Smriti Bhotika, Ph.D. – Former Postdoctoral Associate, Department of Entomology and Nematology, University of Florida • Monica Elliott, Ph.D. – Former Professor of Plant Pathology, Fort Lauderdale Research and Education Center

18 Collaborating Agencies • U.S. Department of Agriculture and Plant Health Inspection Service (USDA-APHIS) • Cooperative Agricultural Pest Survey Program (CAPS) • Florida Department of Agriculture and Consumer Services (FDACS), Division of Plant Industry • National Plant Diagnostic Network (NPDN) • Sentinel Plant Network (SPN) • Protect U.S. • University of Florida Institute of Food and Agricultural Sciences (UF-IFAS)

19 Educational Disclaimer and Citation

• This presentation can be used for educational purposes for NON- PROFIT workshops, trainings, etc.

• Citation: – McAmis, S., Hodges, A., Harrison, N., Shin, K., 2014. Lethal Bronzing Disease, January 2021.

20 References

• Bahder B. W. & E. E. Helmick. 2019. Lethal Bronzing Disease (LBD) (PP243). Gainesville: University of Florida Institute of Food and Agricultural Sciences. Accessed January 29, 2020. – https://edis.ifas.ufl.edu/pdffiles/PP/PP16300.pdf • Halbert. S. 2008. Pest Alert: Texas Phoenix Palm Decline. Florida Department of Agriculture and Consumer Sciences, Division of Plant Industry. Accessed November 22, 2013 – http://www.freshfromflorida.com/Divisions-Offices/Plant-Industry/Plant-Industry-Publications/Pest- Alerts/Pest-Alerts- Texas-Phoenix-Palm-Decline • Halbert, S.E., B. Bextine, S.B. Youngblood, and A.A. Dickens. 2013. Texas phoenix palm decline and potential vectors. APS and MSA joint meeting. 68-S. Accessed November-23, 2013 – http://www.apsnet.org/meetings/Documents/2013_Meeting_Abstracts/aps2013abS68.htm • Halbert, S.E., Wilson, S.W., Bextine, B., and Youngblood, S.B. 2014. Potential planthopper vectors of palm phytoplasmas in Florida with a description of a new species of the genus Omolicna (: Fulgoroidea). Florida Entomologist (in press). • Harrison, N. A., E. E. Helmick, M. L. Elliott. 2008. Lethal yellowing-type diseases of palms associated with phytoplasmas newly identified in Florida, USA. Annals of Applied Biology 153:85-94. • Harrison, N. A., E. E. Helmick, M. L. Elliott. 2008. Lethal yellowing-type diseases of palms associated with phytoplasmas newly identified in Florida, USA. Annals of Applied Biology 153:85-94.

21 References

• Harrison, N. A., E. E. Helmick, M. L. Elliott. 2009. First report of a phytoplasma-associated lethal decline of Sabal palmetto in Florida, USA. Plant Pathology 58:792. • Harrison, N.A., M. Womack, and M.L. Carpio. 2002. Detection and characterization of a lethal yellowing (16SrIV) group phytoplasma in Canary island date palms affected by lethal decline in Texas. Plant Disease 86(6): 676-681. Accessed December 5, 2013 - – http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2002.86.6.676 • Harrison, N. and M. Elliott. 2007. Revised 2013. Texas Phoenix Palm Decline. University of Florida, Institute of Food and Agricultural Sciences. Accessed October 21, 2013 – http://edis.ifas.ufl.edu/pp163 • Jeyaprakash, A. B. D. Sutton, S. E. Halbert and T. S. Schubert. 2011. High-fidelity PCR facilitates detection and identification of a Texas Phoenix palm phytoplasma strain from pigmy date palm, Phoenix roebelenii in Florida. Plant Disease 95: 1475. Accessed July 19, 2013 – http://www.apsnet.org/publications/plantdisease/2011/November/Pages/ 95_11_1475.1.aspx

22 References

• Lucid Key. A resource for pests and diseases of cultivated palms, symptoms of diseases and disorders - Texas Phoenix Palm Decline. Accessed November 22, 2013 – http://itp.lucidcentral.org/id/palms/symptoms/Texas_Phoenix_Palm_Decline.htm • Oropeza, C., I. Cordova, M. Narvaez, and N. Harrison. Palm Trunk Sampling for DNA Extraction and Phytoplasma Detection. – http://flrec.ifas.ufl.edu/pdfs/LY-TPPD-Trunk-Sampling.pdf • Ong, K and S. McBride. 2009. Palm diseases Caused by Phytoplasmas in Texas. AgriLife Extension, Texas A& M system. Accessed January 21, 2014 – http://www.npdn.org/webfm_send/1065 • Texas Department of Agriculture. Texas Phoenix Palm Decline. Accessed October 21, 2013 – http://www.texasagriculture.gov/RegulatoryPrograms/PlantQuality/PestandDiseaseAlerts/DatePalmLethalDecline.aspx

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