Source: UNIVERSITY OF FLORIDA submitted to
FUNGAL DISEASES OF ORNAMENTAL PALMS IN FLORIDA
Sponsoring Institution
State Agricultural Experiment Station
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0207036
Grant No.
(N/A)
Project No.
FLA-FTL-04515
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
May 1, 2006
Project End Date
Apr 30, 2011
Grant Year
(N/A)
Project Director
Elliott, M. L.
Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611
Performing Department
FT. LAUDERDALE RESEARCH & EDUCATION CENTER
Non Technical Summary
Palms define Florida, whether in a landscape or natural setting. Despite the prominence of palms in Florida, research on the fungal diseases of palms, especially mature palms, has been minimal. The majority of UF-IFAS recommendations for diseases of mature palms are either educated guesses, based on research from another climate (often from another continent), or extension of research on seedlings and juvenile palms growing in containers to mature palms growing in the landscape. This project will examine four palm diseases to determine etiology, epimediology and/or control methods.
Animal Health Component
60%
Research Effort Categories
Basic
40%
Applied
60%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2121847110240%
2121847116060%
Knowledge Area
212 - Pathogens and Nematodes Affecting Plants;

Subject Of Investigation
1847 - Palm;

Field Of Science
1160 - Pathology; 1102 - Mycology;
Goals / Objectives
1. Determine diversity of tar spot fungi associated with petiole (rachis) blight of ornamental palms in Florida. 2. Determine incubation period for the trunk rot caused by Thielaviopsis paradoxa. 3. Determine if there is a seasonal sporulation period for Graphiola phoenicis, cause of a common leaf spot on Phoenix species. 4. Determine the etiological agent for a new disease affecting Syagrus romanzoffiana (queen palm).
Project Methods
1. Determine diversity of tar spot fungi associated with petiole/rachis blight of ornamental palms in Florida. Requests will be made to personnel throughout the state to forward palm leaf samples that exhibit typical symptoms of petiole/rachis blight. If fungal structures are already visible on the petiole, these will be examined microscopically and identified using the appropriate monographs. If not, then petiole pieces will be washed thoroughly with tap water, surface sterilized, and placed in a high-humidity container. Attempts will be made to culture the fungi that erupt from the petiole tissue. DNA will be extracted from either a culture or spores on tissue to amplify internally transcribed space regions of nuclear rRNA using the primers ITS1 and ITS4. The resulting amplification products will be sequenced and then compared to other ITS sequences submitted to GenBank. 2. Determine incubation period for the trunk rot caused by Thielaviopsis paradoxa. Cocos nucifera with at least 6 ft of wood and located at the FLREC will be wounded by drilling (10 mm diam x 2.5 cm deep) into the trunk half way between the soil and canopy. T. paradoxa treatments will include inoculation with endospores and chlamydospores by spraying spore suspension into the wound hole, and inoculation with infested coconut raffia placed into the wound hole. Treated portions of the trunk will be wrapped with wet burlap encased in plastic. This wrapping will remain in place for one week, and then removed. Palms will be monitored monthly for symptoms for one year. 3. Determine if there is a seasonal sporulation period for Graphiola phoenicis, cause of a common leaf spot on Phoenix species. P. dactylifera (and hybrids thereof) at the FLREC will be selected for these experiments as they are naturally infected with G. phoenicis. For one group of three plants, four leaves will be selected from each plant, representing leaves of 1 and 2 years of age. All leaflets with sunken sori and sori with emerging filaments will be removed. Remaining leaflets will be examined every three weeks for a year for spore release of sori present and for development of new sori. For a second group of three plants, four leaves will be selected from each plant. All leaflets with leaf spots and sori in any stage of development will be removed. Remaining leaflets will be examined every three weeks for a year for development of new sori and subsequent spore release. 4. Determine the etiological agent for a new disease affecting Syagrus romanzoffiana (queen palm). Preliminary examination of queen palms exhibiting symptoms of a new disease indicates that a Fusarium species or formae specialis of F. oxysporum is the pathogen. Fusarium-type colonies were collected over the past year and will continue to be collected. Isolates will be identified based on morphological and molecular techniques. Methods to complete Kochs postulates will be implemented.

Progress 05/01/06 to 04/30/11

Outputs
OUTPUTS: Palm leaves exhibiting typical petiole/rachis blight symptoms were obtained from Washingtonia robusta, Latania loddigesii, Copernicia x burretiana, Phoenix canariensis (multiple samples), Sabal palmetto (two samples) and a Thrinax sp. Petiole tissue was incubated in moisture chambers. Resulting fungal growth was examined and morphologically and molecularly characterized and compared. Single spore isolates were obtained from most of these fungi, which are generally considered non-culturable, and most isolates produced perithecia with ascospores. Cultured isolates were compared morphologically and molecularly with fungal material on palm tissue. Studies were conducted to determine the etiological agent of a new lethal disease of Syagrus romanzoffiana and W. robusta. Pathogenicity studies were conducted with seedlings and juveniles of these two palm species using Fusarium oxysporum, F. proliferatum or F. semitectum isolates. After isolating the same F. oxysporum f. sp. from a mule palm (S. romanzoffiana x Butia capitata) and P. canariensis, pathogenicity studies were expanded to include these 2 palm species plus P. sylvestris, P. dactylifera (from seed, not clones), P. reclinata and W. filifera. Additional pathogenicity tests with the F. oxysporum isolates were conducted with seedlings of 6 palm species common in the Florida landscape - P. roebelenii, Chamaerops humilus, Dypsis lutescens, Adonidia merrillii, Ravenea rivulis, and Livistona chinensis. Analysis of a portion of the Fusarium tef-1 alpha gene was completed for all isolates obtained from symptomatic palms. This information was combined with ISG sequences for phylogenetic analysis of these isolates and comparison with other known F. oxysporum ff. spp. F. oxysporum f. sp. canariensis (Foc) was isolated from symptomatic P. canariensis and P. sylvestris (same nursery) and P. reclinata (landscape). Cross-pathogenicity tests were established with seedlings of each species with these isolates; P. dactylifera was also included as a host. After isolating Foc from P. canariensis growing in landscapes in Texas and South Carolina, pathogenicity studies were initiated with these isolates on P. canariensis seedlings. Consultations and diagnostic services were provided to clientele in Florida, South Carolina, Texas, Ecuador and Colombia regarding palm fungal diseases and palm phytoplasma diseases. Information regarding palm diseases was disseminated via: 2-day workshops (2-3 each year) open to county Extension faculty and professionals associated with nursery and landscape industries; county-sponsored training programs (nursery and landscape professionals in Florida and Texas); conferences (e.g., FNGLA); Florida ISA programs (arborists). The second edition of a palm disorder and disease diagnostic card deck was produced and printed in both English and Spanish. A LUCID tool for diagnosis of palm problems based on symptoms (disease, disorders and insect damage) was developed, along with 19 palm disease fact sheets to accompany the tool, and is available to everyone at ttp://itp.lucidcentral.org/id/palms/symptoms. PARTICIPANTS: Monica L. Elliott, Principal Investigator, was coordinator for all diagnostics, laboratory and greenhouse research and outreach associated with this project. Elizabeth Des Jardin, Biological Scientist,was responsible for all laboratory work associated with this project. Ian Maquire, Biological Scientist, aided in the outreach efforts associated with development of the LUCID keys and associated fact sheets. Florida Nursery, Growers and Landscape Association. International Society for Arboriculture. International Palm Society. A 2-day workshop was provided two to three times each year to professional landscapers and arborists, nursery professionals, Extension professionals and others associated with palm production. This workshop included information regarding palm diseases. Shorter programs highlighting palm diseases were offered to these groups and to the homeowner via Extension outreach efforts. TARGET AUDIENCES: Professional landscapers and arborists (private and public), nursery growers and homeowners were served by this project. These groups include persons from all racial and ethnic backgrounds. A 2-day workshop was provided two to three times each year to professional landscapers and arborists, nursery professionals, Extension professionals and others associated with palm production. This workshop included information regarding palm diseases. Shorter programs highlighting palm diseases were offered to these groups and to the homeowner via Extension outreach efforts. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Research determined that Cocoicola californica was present on Washingtonia robusta in Florida. This palm pathogen was previously only known to occur in California and only on W. filifera. It has been observed repeatedly on W. robusta since first identified in 2006. The host range of Serenomyces was expanded in Florida to Lantania loddigesii, Copernicia x burretiana, Phoenix canariensis, Sabal palmetto and a Thrinax sp. While the Serenomyces sp. ascospores from the Florida palms most closely conform in size and shape to those of S. phoenicis, the neck length associated with the ascomata does not. S. phoenicis has a neck length of less than 600 microns, whereas the neck length of the Florida palm Serenomyces sp. is at least 1500 microns. This Serenomyces sp. may represent a new species. This is the first report of a Serenomyces sp. on these palm species in Florida and the United States. Initial morphological and molecular characteristics (sequencing of ITS region) of the isolates indicate they are similar to each other and yet different from each other based on the palm host. We obtained single-spore isolates of Serenomyces and were able to induce production of perithecia and ascospores. This has not been reported previously. Characteristics of the cultured isolates matched those of the ascomata and ascospores associated with the palm tissue, both morphologically and molecularly. Based on ITS sequences, there are slight bp differences among the Serenomyces isolates and the differences appear to be associated with palm host. The fungus causing a new lethal disease primarily observed on Syagrus romanazoffiana and W. robusta was determined to be Fusarium oxysporum f. sp. palmarum (Fop), a new formae speciales of Fusarium oxysporum not known to occur anywhere else in the world. There have been single location sites where Fop was isolated from a mule palm (S. romanzoffiana x Butia capitata) and P. canariensis. In collaboration with K. O'Donnell, USDA-ARS, it was determined that there are three haplotypes of this fungus in Florida (ST250, 251 and 284), based on comparison of TEF and IGS sequences. Pathogenicity studies have been conducted with all three haplotypes, and the results indicate the haplotypes are all pathogenic and equally virulent on these palm species - i.e., there is no host specificity associated with the haplotypes. Pathogenicity results were ambiguous for B. capitata, one of the parents of the mule palm. All three sequence types of Fop were equally pathogenic on W. filifera. However, to date, the fungus has only been observed on W. robusta and not W. filifera, but few W. filifera are grown in Florida. Pathogenicity studies on P. roebelenii, Chamaerops humilus, Dypsis lutescens, Adonidia merrillii, Ravenea rivulis, and Livistona chinensis using Fop indicated these palm hosts do not appear to be susceptible to Fop. F. oxysporum f. sp. canariensis was isolated from a Fusarium wilt symptomatic Phoenix canariensis growing in landscapes in South Carolina and Texas. This is the first time this pathogen has been reported in these states.

Publications

  • No publications reported this period


Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: Pathogenicity studies were continued with the new formae speciales of Fusarium oxysporum - F. o. palmarum - using all three sequence types (ST). Seedlings of palm species included in the studies were S. romanzoffiana, B. capitata, mule palm, Washingtonia robusta, and W. filifera. Cross-pathogenicity studies were continued with Fusarium oxysporum f. sp. canariensis isolated from Phoenix sylvestris, Phoenix canariensis and Phoenix reclinata and with Fusarium oxysporum f. sp. palmarum (two sequence types) isolated from Syagrus romanzoffiana and Washingtonia robusta. Seedling palm hosts included were Phoenix sylvestris, P. canariensis, P. reclinata, seed-grown P. dactylifera, and Washingtonia robusta. Pathogenicity studies were continued on P. canariensis seedlings with Fusarium oxysporum f. sp. canariensis isolated from Fusarium wilt symptomatic P. canariensis from Texas and South Carolina. Pathogenicity studies were initiated on P. canariensis seedlings with Fusarium oxysporum f. sp. palmarum isolated from Fusarium wilt symptomatic P. canariensis from Florida. Studies were initiated to examine the uptake and relocation of systemic fungicides infused into coconut palm trunks or applied as soil drenches. Three fungicides (thiobendazole, propiconazole and tebuconazole were infused into the trunks. One fungicide (thiophanate methyl) was used as a soil drench. Bioassays were conducted at monthly intervals for 4 months to detect the fungicides in leaflet, rachis and petiole tissue using a sensitive Penicillium sp. isolate and Fusarium oxysporum f. sp. palmarum isolate. Consultations and diagnostic services were provided to clientele in Florida and Brazil regarding palm fungal diseases and palm phytoplasma diseases. Information regarding palm diseases was disseminated via three 2-day workshops, county-sponsored training programs for nurserypersonnel, landscape personnel and homeowners, and Florida ISA sponsored programs (arborists). A Lucid tool for diagnosis of palm problems based on symptoms (disease, disorders and insect damage) was developed, along with fact sheets to accompany the tool. This tools is available to everyone via the world wide web. PARTICIPANTS: Individuals: Monica L. Elliott, Principal Investigator Elizabeth Des Jardin, Biological Scientist Ian Maquire, Biological Scientist Partner Organizations: International Society for Arboriculture Training Development: A 2-day workshop was provided three times to professional landscapers and arborists. This workshop included information regarding palm diseases. Shorter programs highlighting palm diseases were offered to these groups and to the homeowner via Extension outreach efforts. TARGET AUDIENCES: Targeted Audiences Professional landscapers and arborists (private and public), nursery growers and homeowners were served by this project. These groups include persons from all racial and ethnic backgrounds. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Fusarium oxysporum f. sp. palmarum isolated from a mule palm was, again, pathogenic on the mule palm seedlings and S. romanzoffiana. Results this time were ambiguous for B. capitata. All three sequence types of this pathogen were equally pathogenic on W. robusta and W. filifera. However, to date, the fungus has only been observed on W. robusta and not W. filifera, but few W. filifera are grown in Florida. For pathogenicity studies using Fusarium oxysporum, the best technique was pouring a spore suspension between the leaf bases and onto the roots with the lower 25% of the root system cut off. F. oxysporum f. sp. palmarum was isolated from a Fusarium wilt symptomatic Phoenix canariensis growing in a Florida landscape and was demonstrated to be pathogenic on this host species. F. oxysporum f. sp. canariensis was isolated from a Fusarium wilt symptomatic Phoenix canariensis growing in a Texas and South Carolina landscape and isolates from each location were demonstrated to be pathogenic on this host species. The systemic fungicides thiabendazole and propiconazole were detected in the leaf tissue of coconut palms infused with these materials into the trunk. Thiabendazole was detected in every assay in all four replicate palms. Propiconazole has not been isolated as consistently. Thiophanate methyl and tebuconazole were not detected at any time after application.

Publications

  • Elliott, M. L., Des Jardin, E. A., O'Donnell, K., Geiser, D. M., Harrison, N. A., and Broschat, T. K. 2010. Fusarium oxysporum f. sp. palmarum, a novel forma specialis causing a lethal disease of Syagrus romanzoffiana and Washingtonia robusta in Florida. Plant Disease 94:31-38.
  • Torres, G. A., Sarria, G. A., Varon, F., Coffey, M. D., Elliott, M. L., and Martinez, G. 2010. First report of bud rot caused by Phytophthora palmivora on African oil palm in Colombia. Plant Disease 94:1163.
  • Harrison, N. A., and Elliott, M. L. 2010. Caring for palms should Texas Phoenix palm decline appear in your community. Florida Arborist. 13(4):1, 6, 8.
  • Harrison, N. A., and Elliott, M. L. 2010. Texas Phoenix palm decline. Sun Coast Facilities Today. August 2010:26-29.
  • Elliott, M. L. 2010. Fusarium wilt of queen palm and Mexican fan palm. PP278. http://edis.ifas.ufl.edu/pp163.
  • Elliott, M. L., and Maguire, I. 2010. Red Ring: http://itp.lucidcentral.org/id/palms/symptoms/Red_Ring.htm
  • Elliott, M. L., and Maguire, I. 2010. Root Rot: http://itp.lucidcentral.org/id/palms/symptoms/Root_Rot.htm
  • Elliott, M. L., and Maguire, I. 2010. Tar Spot: http://itp.lucidcentral.org/id/palms/symptoms/Tar_Spot.htm
  • Elliott, M. L., and Maguire, I. 2010. Texas Phoenix Palm Decline: http://itp.lucidcentral.org/id/palms/symptoms/Texas_Phoenix_Palm_Decl ine.htm
  • Elliott, M. L., and Maguire, I. 2010. Thielaviopsis Trunk Rot: http://itp.lucidcentral.org/id/palms/symptoms/Thielaviopsis_Trunk_Rot .htm
  • Broschat, T. K., Elliott, M. L., and Maguire, I. 2010. Symptoms of Diseases and Disorders. In: A Resource for Pests and Diseases of Cultivated Palms. University of Florida, Identification Technology Program, CPHST, PPQ, APHIS, USDA; Fort Collins, Co. http://itp.lucidcentral.org/id/palms/symptoms
  • Fact sheets included in the above 2010 Lucid tool are listed below.
  • Elliott, M. L., and Maguire, I. 2010. Bud Rot http://itp.lucidcentral.org/id/palms/symptoms/Bud_Rot.htm
  • Elliott, M. L., and Maguire, I. 2010. Damping-off: http://itp.lucidcentral.org/id/palms/symptoms/Damping-off.htm
  • Elliott, M. L., and Maguire, I. 2010. Fusarium Wilt of Canary Island Date Palm: http://itp.lucidcentral.org/id/palms/symptoms/Fusarium_Wilt_of_Canary _Island_Date_Palm.htm
  • Elliott, M. L., and Maguire, I. 2010. Fusarium Wilt of Queen and Mexican Fan Palms: http://itp.lucidcentral.org/id/palms/symptoms/Fusarium_Wilt_of_Queen_ and_Mexican_Fan_Palms.htm
  • Elliott, M. L., and Maguire, I. 2010. Ganoderma Butt Rot: http://itp.lucidcentral.org/id/palms/symptoms/Ganoderma_Butt_Rot.htm
  • Elliott, M. L., and Maguire, I. 2010. Gliocladium Blight and Gliocladium Trunk Rot: http://itp.lucidcentral.org/id/palms/symptoms/Gliocladium_Blight_and_ Gliocladium_Trunk_Rot.htm
  • Elliott, M. L., and Maguire, I. 2010. Graphiola Leaf Spot: http://itp.lucidcentral.org/id/palms/symptoms/Graphioa_Leaf_Spot.htm
  • Elliott, M. L., and Maguire, I. 2010. Hartrot and Marchitez Sorpresiva: http://itp.lucidcentral.org/id/palms/symptoms/Hartrot_andMarchitez_So rpresiva.htm
  • Elliott, M. L., and Maguire, I. 2010. Diamond Scale: http://itp.lucidcentral.org/id/palms/symptoms/Diamond_Scale.htm
  • Elliott, M. L., and Maguire, I. 2010. Leaf Spots and Leaf Blights: http://itp.lucidcentral.org/id/palms/symptoms/Leaf_Spots_and_Leaf_Bli ghts.htm
  • Elliott, M. L., and Maguire, I. 2010. Lethal Yellowing: http://itp.lucidcentral.org/id/palms/symptoms/Lethal_Yellowing.htm
  • Elliott, M. L., and Maguire, I. 2010. Pestalotiopsis Rachis Blight and Crown Rot: http://itp.lucidcentral.org/id/palms/symptoms/Pestalotioposis_Rachis_ Blight_and_Crown_Rot.htm
  • Elliott, M. L., and Maguire, I. 2010. Petiole (Rachis) Blight: http://itp.lucidcentral.org/id/palms/symptoms/Petiole_(Rachis)_Blight .htm


Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Pathogenicity studies were continued with the new formae speciales of Fusarium oxysporum - F. o. palmarum - using all three sequence types (ST). ST284 had been isolated from the interspecific cross between Syagrus romanzoffiana and Butia capitata, which is often referred to as a mule palm. Seedlings of palm species included in the studies were S. romanzoffiana, B. capitata, mule palm, Washingtonia robusta, and W. filifera. Cross-pathogenicity studies were continued with Fusarium oxysporum f. sp. canariensis isolated from Phoenix sylvestris, Phoenix canariensis and Phoenix reclinata and with Fusarium oxysporum f. sp. palmarum (two sequence types) isolated from Syagrus romanzoffiana and Washingtonia robusta. Seedling palm hosts included were Phoenix sylvestris, P. canariensis, P. reclinata, seed-grown P. dactylifera, and Washingtonia robusta. Pathogenicity studies were initiated on P. canariensis seedlings with Fusarium oxysporum f. sp. canariensis isolated from Fusarium wilt symptomatic P. canariensis from Texas. Consultations and diagnostic services were provided to clientele in Florida, South Carolina, Texas, Ecuador and Colombia regarding palm fungal diseases and palm phytoplasma diseases. Information regarding palm diseases was disseminated via three 2-day workshops, county-sponsored training programs for nursery and landscape personnel, and Florida ISA sponsored programs (arborists). The second edition of a palm diagnostic card deck was produced in both English and Spanish. PARTICIPANTS: Individuals:Monica L. Elliott, Principal Investigator; Elizabeth Des Jardin, Biological Scientist. Partner Organizations:International Palm Society. Collaborator:Timothy K. Broschat, Nigel A. Harrison. Training Development: A 2-day workshop was provided three times to professional landscapers and arborists. This workshop included information regarding palm diseases. Shorter programs highlighting palm diseases were offered to these groups and to the homeowner via Extension outreach efforts. TARGET AUDIENCES: Professional landscapers and arborists (private and public) plus homeowners were served by this project. These groups include persons from all racial and ethnic backgrounds. Programs are offered to professionals and non-professionals to increase their knowledge about palm diseases, diagnosis and management. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Fusarium oxysporum f. sp. palmarum isolated from a mule palm was pathogenic on the mule palm seedlings and S. romanzoffiana, but not B. capitata. All three sequence types of this pathogen were equally pathogenic on W. robusta and W. filifera. However, to date, the fungus has only been observed on W. robusta and not W. filifera. No isolate of F. oxysporum f. sp. canariensis produced typical Fusarium wilt symptoms on any host, but one isolate did cause a severe decline, as measured by dry weight, on Phoenix species but not W. robusta. F. oxysporum f. sp. palmarum ST 251 killed W. robusta and seed-grown P. dactylifera and caused a significant decline of other Phoenix species. F. oxysporum f. sp. palmarum ST250 killed W. robusta and caused a significant decline of the Phoenix species. F. oxysporum f. sp. palmarum was isolated from a Fusarium wilt symptomatic Phoenix canariensis growing in a Florida landscape. F. oxysporum f. sp. canariensis was isolated from a Fusarium wilt symptomatic Phoenix canariensis growing in a South Carolina landscape.

Publications

  • ODonnell, K., Gueidan, C., Sink, S. Johnston, P. R., Crous, P. W., Glenn, A., Riley, R., Zitomer, N. C., Colyer, P., Waalwijk, C., van der Lee, T., Moretti, A., Kang, S., Kim, H.-S., Geiser, D. M., Juba, J. H., Baayen, R. P., Cromey, M. G., Bithell, S., Sutton, D.A., Skovgaard, K., Ploetz, R., Kistler, H. C., Elliott, M., Davis, M., and Sarver, B. A. J. 2009. A two-locus DNA sequence database for typing plant and human pathogens within the Fusarium oxysporum species complex. Fungal Genetics and Biology 46:936-948.
  • Restom Gaskill, D. A., Harrison, N. A., Elliott, M. L. and Smith, T. R. 2009. Current distribution of Texas Phoenix palm decline in Florida. 2009 Caribbean Division Meeting Abstracts. Electronic conference proceedings (abstract) on line at www.apsnet.org/meetings/div/cr09abs.asp.
  • Sarria, G. A., Torres, G. A., Velez, D. C., Rodriguez, J., Norena, C., Varon, F., Coffey, M., Elliott, M., and Martinez, G. 2008. Caracterizacion morfologica y molecular de Phytophthora palmivora agente causal de las lesions iniciales de la pudricion del cogollo (PC) de la palma de aceite en Colombia. Fitopatologia Colombiana 32(2):39-44.
  • Harrison, N. A., Helmick, E. E., and Elliott, M. L. 2009. First report of a phytoplasma-associated lethal decline of Sabal palmetto in Florida, USA. Plant Pathology 58:792.
  • Elliott, M. L. 2009. Emerging palm diseases in Florida. HortTechnology 19:717-718.
  • Downer, A. J., Uchida, J. Y., Hodel, D. R., and Elliott, M. L. 2009. Lethal palm diseases common in the United States. HortTechnology 19:710-716.


Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Sabal palmetto leaves exhibiting typical symptoms of petiole (rachis) blight were obtained from both the west and east coasts of Florida. Petiole tissue was incubated in moisture chambers to determine fungal genera causing the symptoms. Resulting fungal growth was examined and morphological characterized. Ascospores collected from the palm tissue was subjected to molecular characterization using PCR and ITS1/ITS4 primers. Research continued on confirming the etiological agent of a new lethal disease of Syagrus romanzoffiana, and Washingtonia robusta. Pathogenicity studies were repeated and expanded upon with these two hosts and the presumed pathogen, a new formae speciales of Fusarium oxysporum. A pathogenicity study was conducted using this fungus on seven palms commonly grown in the Florida landscape - Phoenix roebelenii, Chamaerops humilus, Dypsis lutescens, Phoenix sylvestris, Adonidia merrillii, Ravenea rivulis, and Livistona chinensis. Cross-pathogenicity studies with previously isolated Fusarium oxysporum f. sp. canariensis from Phoenix sylvestris and Phoenix canariensis were initiated with seedling and juvenile palms. Isolations were made from a Phoenix reclinata exhibiting typical symptoms of Fusarium wilt. Consultations and diagnostic services were provided to clientele in Florida regarding Fusarium diseases of palms, other palm fungal diseases and palm phytoplasma diseases. Information regarding the new Fusarium disease and the new palm phytoplasma diseases was disseminated via two 2-day workshops, conferences (FNGLA; nursery and landscape industry), county-sponsored training programs for nursery and landscape personnel, and FL ISA sponsored programs (arborists). PARTICIPANTS: Individuals: Monica L. Elliott, Principal Investigator Elizabeth Des Jardin, Biological Scientist Partner Organizations: Florida Nursery Growers and Landscape Association (external funding) Collaborators: Kerry O'Donnell, USDA-ARS, collaborated on the molecular characterization of the new Fusarium oxysporum. Training Development: A 2-day workshop was provided twice to the professional landscapers and arborists. This workshop included information regarding palm diseases. Programs highlighting palm diseases were offered to these groups and to the homeowner via Extension outreach efforts. TARGET AUDIENCES: Professional landscapers and arborists (private and public) plus homeowners were served by this project. These groups include persons from all racial and ethnic backgrounds. A 2-day workshop was provided twice (May and October ) to professional landscapers and arborists. This workshop included information regarding palm diseases. Programs highlighting palm diseases were offered to these groups and to the homeowner via Extension outreach efforts. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
A Serenomyces species emerged from the Sabal palmetto petiole tissue, the same genus that has been observed in Thrinax, Latania, Phoenix, and Copernicia x burretiana. Initial morphological and molecular characteristics (sequencing of ITS region) of the S. palmetto isolates indicate they are similar to each other but different from the isolates obtained from the other palm hosts. Results to date indicate that a new formae speciales of Fusarium oxysporum is the pathogen of the lethal disease observed on Syagrus romanazoffiana and Washingtonia robusta. In collaboration with K. O'Donnell, USDA-ARS, it was determined that there are three haplotypes of this fungus in Florida, based on comparison of TEF and IGS sequences. Pathogenicity studies have been conducted with two of the haplotypes (250 and 251), and the results indicate the two haplotypes are both pathogenic and equally virulent on both palm species. A pathogenicity study was conducted using these same two hapotypes on seven palms commonly grown in Florida - Phoenix roebelenii, Chamaerops humilus, Dypsis lutescens, Phoenix sylvestris, Adonidia merrillii, Ravenea rivulis, and Livistona chinensis. None of these species were affected by the new F. oxysporum, whereas S. romanzoffiana and W. robusta were killed within 3 months of inoculation. A presumed Fusarium oxysporum f. sp. canariensis (based on positive results with Foc primers and TEF sequences) was isolated from Phoenix reclinata. Cross-pathogenicity studies with previously isolated F. o. canariensis from P. sylvestris and P. canariensis have not resulted in expression of typical Fusarium wilt symptoms on seedling or juvenile palms. A 50 percent growth reduction was observed with the P. sylvestris isolate, but only on P. canariensis juveniles.

Publications

  • Harrison, N.A., and Elliott, M.L. 2008. Lethal yellowing of palms. The Plant Health Instructor. doi: 10.1094/PHI-I-2008-0714-01
  • Harrison, N.A., Helmick, E.E., and Elliott, M.L. 2008. Lethal yellowing-type diseases of palms associated with phytoplasmas newly identified in Florida, USA. Annals of Applied Biology. 153: 85-94. doi: 10.1111/j.1744-7348.2008.00240.x
  • Harrison, N.A., and Elliott, M.L. 2008. A lethal disease of Sabal palmetto on Florida's Central West Coast. http://flrec.ifas.ufl.edu/palm_prod/pdfs/Sabal-palmetto-Infected-with -Phytoplasma-in-Florida.pdf
  • Elliott, M.L., and Broschat, T.K. 2008. Palm problems: Field and laboratory diagnosis. PP246. University of Florida - IFAS Extension, Gainesville, FL http://edis.ifas.ufl.edu/PP166
  • Broschat, T.K., and Elliott, M.L. 2008. Palm Problems: A Key to Common Landscape Palm Disorders and Diseases in the Continental United States http://flrec.ifas.ufl.edu/palm_prod/palm_problems.shtml
  • O'Donnell, K., Johnston, P, Crous, P., Colyer, P., Glenn, A., Riley, R., Zitomer, N., Waalwijk, C., Geiser, D., Kang, S., Juba, J., Sutton, D.A., Ploetz, R., Elliott, M., Kistler, H.C., Davis, M., Sink, S., and Sarver, B. 2008. A two-locus DNA sequence database for identifying host-specific pathogens and phylogenetic diversity within the Fusarium oxysporum species complex. 9th International Congress of Plant Pathology, August 24-29, 2008, Torino, Italy
  • Elliott, M.L., and Des Jardin, E.A. 2008. A new lethal disease of Syagrus romanzoffiana and Washingtonia robusta in Florida is caused by Fusarium oxysporum. Proceedings of the 44th Annual Caribbean Food Crops Society Meeting, July 13-17, Miami, FL.


Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: Palm leaves exhibiting typical symptoms of petiole/rachis blight were obtained from Latania loddigesii (Pinellas Co., FL), Copernicia x burretiana (Miami-Dade Co., FL) and Phoenix canariensis (Miami-Dade Co., FL). Petiole tissue was incubated in moisture chambers to determine fungal genera causing the symptoms. Resulting growth was examined and morphologically characterized and compared. Research continued on determining etiological agent of a new lethal disease of Syagrus romanzoffiana (queen palm). Pathogenicity studies were conducted with seedlings and juvenile palms using F. oxysporum, F. proliferatum or F. semitectum isolates. Analysis of a portion of the tef-1 alpha gene of Fusarium was continued. Dying Washingtonia robusta (Mexican fan palm) from field nursery (Lee Co., FL) and landscape sites (Pinellas Co. and Orange Co., FL) were examined and determined to be infected with a F. oxysporum. Likewise, a Syagrus x Butia (Pinellas Co., FL) was also diagnosed with F. oxysporum as the potential pathogen. Cross-pathogenicity tests with the F. oxysporum isolates from S. romanzoffiana and W. robusta were conducted with seedling palms of each species. Fusarium oxysporum was isolated from Fusarium wilt symptomatic Phoenix canariensis and P. sylvestris growing in the same nursery field site (Hillsborough Co., FL). Cross-pathogenicity tests were established with seedling palms of each species using F. oxysporum isolates from each palm species. Analysis of the tef-1 alpha gene was conducted on the isolates obtained from each palm species. A Fusarium species was isolated from dying Ravenea rivularis (Majesty palm)(Lee Co., FL). Analysis of the tef-1 alpha gene was conducted and pathogenicity tests initiated using seedling R. rivularis. Consultations and diagnostic services were provided to clientele in Florida regarding Fusarium diseases of palms and other diseases. Information regarding the new Fusarium disease was disseminated via text and photos placed on the FLREC website, with an announcement to all Florida county horticulture agents. Information was also disseminated via a workshop (2-day palm school at the FLREC for county agents and select landscape personnel), conferences (FNGLA; nursery and landscape industry), county-sponsored training programs for nursery and landscape personnel, and FL ISA sponsored programs (arborists). PARTICIPANTS: Partner Organization: Florida Nurseries, Growers and Landscape Association (FNGLA) TARGET AUDIENCES: Target audiences include growers, landscapers and homeowners - any one who grows, manages or owns a palm. Information is disseminated via extension publications and programs sponsored by organizations, private companies and county Extension service offices.

Impacts
For all three palm species (L. loddigesii, Copernicia x burretiana and P. canariensis), stromata with multiple ostiolar dots and long (1500 microns), cylindrical, black necks (beaks) discharging a reddish-brown, cirrhus-like mass of ascospores were observed protruding from the petiole surface. Ascospores were unicellular, ovoid with obtuse ends, and pale reddish-brown. The average ascospore size (microns) was 13.4x7.0, 13.4x6.2 and 12.8x7.3 from L. loddigesii, Copernicia x burretiana and P. canariensis, respectively. The fungus from each palm was identified as Serenomyces Petr. While the Serenomyces sp. ascospores from the Florida palms most closely conform in size and shape to those of S. phoenicis, the neck length does not. S. phoenicis has a neck length of less than 600 microns, whereas the neck length of the Florida palm Serenomyces sp. is at least 1500 microns. This Serenomyces sp. may represent a new species. This is the first report of a Serenomyces sp. on these three palm species in Florida and the United States. Pathogenicity studies demonstrate that F. oxysporum is the pathogen responsible for the new disease of S. romanzoffiana, and not F. proliferatum or F. semitectum. Comparison of the tef gene sequence from the S. romanzoffiana isolates indicates this F. oxysporum does not have a close match with any of the known F. oxysporum pathogens in the current data base. Sequencing of the F. oxysporum isolates from W. robusta and Syagrus x Butia were an exact match to those from S. romanzoffiana. This was the first time that this F. oxysporum had been isolated from these palm species. Cross-pathogenicity tests demonstrate that F. oxysporum isolates from S. romanzoffiana are pathogenic on W. robusta and vice versa, thus extending the host range of this new F. oxysporum. Results from sequencing a portion of the tef-1 alpha gene of F. oxysporum isolates from P. canariensis and P. sylvestris showed that the isolates were both F. o. canariensis. This is the first time that F. o. canariensis has been isolated from P. sylvestris. Disease development has not occurred thus far in the cross-pathogenicity tests. The Fusarium species isolated from dying R. rivularis (Majesty palm) was identified as F. solani based on sequencing of a portion of the tef gene. This is the first time this fungus has been isolated from R. rivularis. Disease development has not occurred thus far in the pathogenicity tests. As a result of the outreach programs, clientele in Florida are aware of the new Fusarium oxysporum causing disease on both S. romanzoffiana and W. robusta.

Publications

  • Elliott, M.L. , and Des Jardin, E.A. 2006. First Report of a Serenomyces sp. from Copernicia x burretiana, Latania loddigesii and Phoenix canariensis in Florida and the United States. Plant Health Progress. doi: 10/1094/PHP-2006-1213-02-BR.
  • Harrison, N.A., and Elliott, M.L. 2007. Reading palms. Ornamental Outlook. 16(10):24-26.
  • Elliott, M.L. 2007. Fusarium decline of queen palms and Mexican fan palms in Florida. Text at http://flrec.ifas.ufl.edu/palm_prod/pdfs/New-Disease-Queen-Palms-Mexi can-Fan-Palms-July.pdf; photos at http://flrec.ifas.ufl.edu/palm_prod/fusarium.shtml


Progress 10/01/05 to 09/30/06

Outputs
Washingtonia robusta (California or desert fan palm) leaf samples from Florida were received that were indicative of petiole (rachis) blight. Incubation of petiole piece in a humidity chamber resulted in production of fungal structures identified as Cocoicola californica. The only other report of this fungus is on Washingtonia filifera (Mexican fan palm) in California. Research continues to determine the etiological agent(s) of a disease that causes sudden death of Syagrus romanzoffiana (queen palm). Three Fusarium species have been isolated and identified from symptomatic tissue: F. semitectum, F. oxysporum, and F. proliferatum. Identification is based on morphology and DNA sequencing of the translation elongation factor 1-alpha. The F. oxysporum isolates are not F. oxysporum f. sp. canariensis, causal agent of Fusarium wilt of Phoenix canariensis. It has been learned that the PCR assay used for identifying F. oxysporum f. sp. canariensis is not as specific as previously thought, as false positive were obtained with a few of the F. proliferatum isolates from S. romanzoffiana. Pathogenicity experiments have been established on juvenile S. romanzoffiana using all three species.

Impacts
Washingtonia robusta (California or desert fan palm ) and Syagrus romanzoffiana (queen palm) are dominant palms in the Florida landscape. Determining the cause of the diseases observed on these palms in the landscape is critical to developing management techniques.

Publications

  • Elliott, M. L. and E. A. Des Jardin. 2006. First report of Cocoicola californica on Washingtonia robusta in Florida. Plant Health Progress doi:10.1094/PHP-2006-0227-01-BR.