scholarly journals Susceptibility to Laurel Wilt and Disease Incidence in Two Rare Plant Species, Pondberry and Pondspice

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1056-1062 ◽  
Author(s):  
S. W. Fraedrich ◽  
T. C. Harrington ◽  
C. A. Bates ◽  
J. Johnson ◽  
L. S. Reid ◽  
...  
Keyword(s):  
South Carolina ◽  
Plant Species ◽  
Disease Incidence ◽  
Rare Plant ◽  
Laurel Wilt ◽  
Xyleborus Glabratus ◽  
Rdna Sequences ◽  
Raffaelea Lauricola ◽  
Close Proximity ◽  
Persea Borbonia

Laurel wilt, caused by Raffaelea lauricola, has been responsible for extensive losses of redbay (Persea borbonia) in South Carolina and Georgia since 2003. Symptoms of the disease have been noted in other species of the Lauraceae such as the federally endangered pondberry (Lindera melissifolia) and the threatened pondspice (Litsea aestivalis). Pondberry and pondspice seedlings were inoculated with R. lauricola from redbay, and both species proved highly susceptible to laurel wilt. Field assessments found substantial mortality of pondberry and pondspice, but in many cases the losses were not attributable to laurel wilt. R. lauricola was isolated from only 4 of 29 symptomatic pondberry plants at one site, but the fungus was not recovered from three plants at another site. R. lauricola was isolated from one of two symptomatic pondspice plants at one site, and from five of 11 plants at another site, but not from any plant at a third site. Insect bore holes, similar to those produced by Xyleborus glabratus (the vector of laurel wilt), were found in some pondberry and pondspice stems, but adults were not found. Damage caused by Xylosandrus compactus was found in pondberry stems, but this ambrosia beetle does not appear to be a vector of R. lauricola. Xyleborinus saxeseni adults were found in a dying pondspice with laurel wilt, and R. lauricola was recovered from two of three adults. Isolates of R. lauricola from pondberry, pondspice, and X. saxeseni had rDNA sequences that were identical to previously characterized isolates, and inoculation tests confirmed that they were pathogenic to redbay. Because pondberry and pondspice tend to be shrubby plants with small stem diameters, these species may not be frequently attacked by X. glabratus unless in close proximity to larger diameter redbay.

scholarly journals First Report of Laurel Wilt Disease Caused by Raffaelea lauricola on Camphor in Florida and Georgia

Plant Disease ◽  
2009 ◽  
Vol 93 (2) ◽  
pp. 198-198 ◽  
Author(s):  
J. A. Smith ◽  
L. Mount ◽  
A. E. Mayfield ◽  
C. A. Bates ◽  
W. A. Lamborn ◽  
...  
Keyword(s):  
South Carolina ◽  
Resistance Mechanisms ◽  
Small Subunit ◽  
Residential Areas ◽  
Laurel Wilt ◽  
Xyleborus Glabratus ◽  
Raffaelea Lauricola ◽  
Redbay Ambrosia Beetle ◽  
Persea Borbonia ◽  
Branch Dieback

Laurel wilt is a recently described (1) vascular disease of redbay (Persea borbonia (L.) Spreng) and other plants in the family Lauraceae. The wilt is caused by Raffaelea lauricola, a fungus vectored by the nonnative redbay ambrosia beetle (Xyleborus glabratus Eichhoff) (1,2). Since 2003, laurel wilt has caused widespread mortality of redbay in Georgia, South Carolina, and Florida (1) and has recently been found on avocado in Florida (4). Since June of 2007, wilted shoots and branch dieback have been observed in several camphor trees (Cinnamomum camphora (L.) Sieb.) in residential areas of McIntosh and Glynn counties in Georgia and Baker County in Florida. Symptomatic camphor trees ranged from 4.5 to 12 m high and occurred in areas where redbay mortality due to laurel wilt has been frequently observed during the last 2 to 3 years. In some camphor trees, only the smaller branches (<2 cm in diameter) were wilting or dead, whereas in other trees (e.g., Baker County, Florida), the larger branches and substantial portions of the crown were also symptomatic. Rapid wilt that affects entire trees that is usually observed in redbay, has not been observed in camphor. Some camphor trees in residential areas of Jekyll Island, Georgia (Glynn County), where extensive wilt of redbay has occurred, have exhibited only localized wilt of some shoots or branches and other camphors remain asymptomatic. Removal of bark from wilted branch sections revealed black-to-brownish staining in the sapwood, characteristic of laurel wilt. Although no evidence of ambrosia beetles was observed on these samples, more extensive surveys are needed to determine the role of this vector in laurel wilt of camphor. Wood chips from symptomatic areas of branches were surface sterilized and plated on cycloheximide-streptomycin malt agar as previously described (1,4) and R. lauricola was routinely isolated. Small subunit (18S) sequences from rDNA were amplified by PCR and sequenced using primers NS1 and NS4 (3). BLASTn searches revealed homology to R. lauricola C2203 (GenBank Accession No. EU123076, 100% similarity, e-value of 0.0, and a total score of 1,886). The small subunit rDNA sequence for this isolate has been deposited into GenBank ( http://www.ncbi.nlm.nih.gov/Genbank/index.html ) and has been assigned Accession No. EU 853303. The presence of laurel wilt in camphor provides an opportunity to understand the pathogen distribution and possible resistance mechanisms in this host, which could have implications for efforts to remediate the impacts of the disease in redbay and other species in the Lauraceae in the southeastern United States. References: (1) S. W Fraedrich et al. Plant Dis. 92:215, 2008. (2) T. C. Harrington et al. Mycotaxon 104:399, 2008. (3) M. A. Innis et al. PCR Protocols, A Guide to Methods and Applications. Academic Press. San Diego, CA, 1990. (4) A. E. Mayfield, III et al. Plant Dis. 92:976, 2008.

A Field-Portable Diagnostic Approach Confirms Laurel Wilt Disease Diagnosis in Minutes Instead of Days

2021 ◽  
Vol 47 (3) ◽  
pp. 98-109
Author(s):  
Jeffrey Hamilton ◽  
Stephen Fraedrich ◽  
Campbell Nairn ◽  
Albert Mayfield ◽  
Caterina Villari
Keyword(s):  
Lamp Assay ◽  
Disease Diagnosis ◽  
Wilt Disease ◽  
Diagnostic Process ◽  
Laurel Wilt ◽  
Xyleborus Glabratus ◽  
Raffaelea Lauricola ◽  
Laurel Wilt Disease ◽  
Persea Borbonia ◽  
Species Specific

Background: Laurel wilt disease has caused the extensive mortality of lauraceous species in the southeastern United States. The causal agent is an invasive fungus, Raffaelea lauricola, which is a symbiont of the beetle Xyleborus glabratus and causes a rapid, fatal vascular wilt. Early diagnosis of laurel wilt is imperative for efficient disease management. The current diagnostic process, however, is slow due to the lengthy laboratory procedures required to confirm pathogen presence. Methods: We tested the robustness and field-portability of a recently developed, species-specific, loop-mediated isothermal amplification (LAMP) assay for R. lauricola, with the overall goal of eliminating the need for a laboratory confirmation of the diagnosis. We tested the robustness of the assay using benchtop equipment with naturally infected samples. We then tested the assay directly in the field using a portable device. Results: The assay successfully detected R. lauricola directly from symptomatic wood tissue using crude DNA extracts. Furthermore, the assay readily allowed users to distinguish between symptoms caused by R. lauricola infection and similar symptoms caused by other agents. In-field, we assayed wood samples from symptomatic redbay (Persea borbonia [L.] Spreng) and sassafras (Sassafras albidum [Nutt.] Nees) across the Southeast and successfully detected R. lauricola-infected trees in less than an hour. Conclusion: Results of this study confirmed that the field-deployable LAMP assay is robust and can rapidly and accurately detect R. lauricola in infected trees directly on-site. LAMP technology is well suited for in-field implementation, and these results serve as an incentive for further development and use of this technology in the field of forest pathology.

scholarly journals First Report of Laurel Wilt Disease Caused by Raffaelea lauricola on Sassafras in Florida and South Carolina

Plant Disease ◽  
2009 ◽  
Vol 93 (10) ◽  
pp. 1079-1079 ◽  
Author(s):  
J. A. Smith ◽  
T. J. Dreaden ◽  
A. E. Mayfield ◽  
A. Boone ◽  
S. W. Fraedrich ◽  
...  
Keyword(s):  
South Carolina ◽  
Small Subunit ◽  
Wilt Disease ◽  
Laurel Wilt ◽  
Rdna Sequences ◽  
Raffaelea Lauricola ◽  
Laurel Wilt Disease ◽  
Redbay Ambrosia Beetle ◽  
Red Bay ◽  
Branch Dieback

Laurel wilt disease, caused by Raffaelea lauricola (T.C. Harr., Fraedrich & Aghayeva sp. nov.), which is a fungal symbiont of the nonnative redbay ambrosia beetle (Xyleborus glabratus Eichhoff), has caused widespread mortality of native redbay (Persea borbonia (L.) Spreng) in Georgia, South Carolina, and Florida since 2002. The disease has been noted on other species in the Lauraceae including sassafras in Georgia (1), and more recently, on avocado and camphor in Florida (4). Since 2005, wilted shoots, branch dieback, and tree death have been observed in sassafras trees (Sassafras albidum (L.)) in Liberty, McIntosh, Chatham, Effingham, Bulloch, Evans, and Screven counties in Georgia; Bamberg, Beaufort, Charleston, Colleton, Hampton, and Orangeburg counties in South Carolina; and Putnam County in Florida. Symptomatic sassafras trees ranged from 1 to 12 m high and 2.5 to 25 cm in diameter at breast height. In contrast to red bay trees that retain wilted foliage, symptomatic sassafras defoliate rapidly as trees wilt and die. Multiple symptomatic ramets originating from a common root system have been observed. Removal of bark from stem and root sections from wilted trees revealed black-to-brownish staining in the sapwood, characteristic of laurel wilt. Wood chips from symptomatic areas of branches and roots were surface sterilized and plated on cycloheximide-streptomycin malt agar as previously described (1) and R. lauricola was routinely isolated. Small subunit (18S) sequences from rDNA were amplified by PCR and sequenced using primers NS1 and NS4 (3) for isolates from sassafras from Florida and South Carolina. BLASTn searches revealed homology to Raffaelea sp. C2203 (GenBank Accession No. EU123076, 100% similarity) described by Fraedrich et al. (1) from redbay and later named R. lauricola (2). The small subunit rDNA sequences for these isolates have been deposited into GenBank ( http://www.ncbi.nlm.nih.gov/Genbank/index.html ) and assigned Accession Nos. EU980448 (Florida) and GQ329704 (South Carolina). Koch's postulates have been completed with R. lauricola on this host previously (1). Laurel wilt on sassafras often was geographically isolated from other symptomatic hosts in Georgia and South Carolina and appears to occur on this host independently of proximity to redbay. Further studies to determine the epidemiology of laurel wilt on sassafras, potential resistance, and impact on sassafras life history and distribution are needed. Given the clonal nature of sassafras, the disease would appear to have the potential to move through roots of trees once established in a stand. References: (1) S. W Fraedrich et al. Plant Dis. 92:215, 2008. (2) T. C. Harrington et al. Mycotaxon 104:399, 2008. (3) M. A. Innis et al. PCR Protocols, A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990. (4) J. A. Smith et al. Plant Dis. 93:198, 2009.

scholarly journals Host density dependence and environmental factors affecting laurel wilt invasion

2019 ◽  
Author(s):  
Robin A. Choudhury ◽  
Hong L. Er ◽  
Marc Hughes ◽  
Jason A. Smith ◽  
Grechen E. Pruett ◽  
...  
Keyword(s):  
South Carolina ◽  
Disease Incidence ◽  
Recursive Partitioning ◽  
Host Density ◽  
South Florida ◽  
Laurel Wilt ◽  
Trunk Diameter ◽  
Raffaelea Lauricola ◽  
Southeastern Us ◽  
Negative Exponential Distribution

AbstractHost size, density and distribution, in addition to climate, can affect the likelihood a pathogen will invade and saturate landscapes. Laurel wilt, caused by the vector-borne forest pathogen Raffaelea lauricola, has devastated populations of native Lauraceae in the Southeastern US, and continues to spread. We surveyed 87 plots in six coastal islands in South Carolina, Georgia and North Florida, and one inland site (Archbold Biological Station) in South Florida for laurel wilt-affected and non-affected individual plants belonging to the genus Persea. The coastal island sites were surveyed once in 2008 or 2009, and the inland site was surveyed eight times from 2011 to 2013. Disease incidence per plot ranged from 0% to 96%, with mean disease incidence 45% across all sites. Disease incidence was positively correlated with trunk diameter and density of hosts with trunk diameter > 5 cm, but negatively with the degree of clustering, which was highest for small trees. A recursive partitioning model indicated that higher disease incidence was associated with moderate temperatures, wider trunk diameter, lower relative humidity, and lower wind speeds. Disease progress over time at Archbold followed a Gompertz curve, plateauing at 3% in two years. The dispersal kernel for disease incidence from a focus followed a negative exponential distribution. The number of plots with diseased trees at Archbold was similar for redbay (P. borbonia) and swampbay (P. palustris), but was lower for silkbay (P. humilis). Understanding how host density, size, and diversity interact with environmental effects will help guide future risk prediction efforts.

scholarly journals Quantification of Propagules of the Laurel Wilt Fungus and Other Mycangial Fungi from the Redbay Ambrosia Beetle, Xyleborus glabratus

2010 ◽  
Vol 100 (10) ◽  
pp. 1118-1123 ◽  
Author(s):  
T. C. Harrington ◽  
S. W. Fraedrich
Keyword(s):  
South Carolina ◽  
Southeastern United States ◽  
Ambrosia Beetle ◽  
Fungal Symbiont ◽  
Laurel Wilt ◽  
Xyleborus Glabratus ◽  
Raffaelea Lauricola ◽  
Redbay Ambrosia Beetle ◽  
Yeast Phase ◽  
Isolated Species

The laurel wilt pathogen, Raffaelea lauricola, is a fungal symbiont of the redbay ambrosia beetle, Xyleborus glabratus, which is native to Asia and was believed to have brought R. lauricola with it to the southeastern United States. Individual X. glabratus beetles from six populations in South Carolina and Georgia were individually macerated in glass tissue grinders and serially diluted to quantify the CFU of fungal symbionts. Six species of Raffaelea were isolated, with up to four species from an individual adult beetle. The Raffaelea spp. were apparently within the protected, paired, mandibular mycangia because they were as numerous in heads as in whole beetles, and surface-sterilized heads or whole bodies yielded as many or more CFU as did nonsterilized heads or whole beetles. R. lauricola was isolated from 40 of the 41 beetles sampled, and it was isolated in the highest numbers, up to 30,000 CFU/beetle. Depending on the population sampled, R. subalba or R. ellipticospora was the next most frequently isolated species. R. arxii, R. fusca, and R. subfusca were only occasionally isolated. The laurel wilt pathogen apparently grows in a yeast phase within the mycangia in competition with other Raffaelea spp.

Raffaelea lauricola. [Distribution map].

2015 ◽  
Author(s):  
Keyword(s):  
North Carolina ◽  
South Carolina ◽  
North America ◽  
Geographical Distribution ◽  
Distribution Map ◽  
Raffaelea Lauricola ◽  
Persea Borbonia ◽  
New Distribution

Abstract A new distribution map is provided for Raffaelea lauricola Harrington, Fraedrich & Aghayeva. Sordariomycetes: Ophiostomatales: Ophiostomataceae. Hosts: Redbay (Persea borbonia), swampbay (P. palustris), avocado (P. americana) and other members of the Lauraceae. Information is given on the geographical distribution in Asia (Japan, Kyushu and Taiwan) and North America (USA, Alabama, Florida, Georgia, Mississippi, North Carolina and South Carolina).

scholarly journals Genetic Analyses of the Laurel Wilt Pathogen, Raffaelea lauricola, in Asia Provide Clues on the Source of the Clone that is Responsible for the Current USA Epidemic

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 37 ◽  
Author(s):  
Tyler J. Dreaden ◽  
Marc A. Hughes ◽  
Randy C. Ploetz ◽  
Adam Black ◽  
Jason A. Smith
Keyword(s):  
Genetic Structure ◽  
Laurel Wilt ◽  
Type Locus ◽  
Xyleborus Glabratus ◽  
Genetic Structure Of Populations ◽  
Raffaelea Lauricola ◽  
Host Trees ◽  
Redbay Ambrosia Beetle ◽  
The Usa ◽  
Simple Sequence

Laurel wilt is caused by the fungus Raffaelea lauricola T.C. Harr., Fraedrich and Aghayeva, a nutritional symbiont of its vector the redbay ambrosia beetle, Xyleborus glabratus Eichhoff. Both are native to Asia but appeared in Georgia in the early 2000s. Laurel wilt has since spread to much of the southeastern United States killing >300 million host trees in the Lauraceae plant family. The aims of this research were to elucidate the genetic structure of populations of R. lauricola, to examine its reproductive strategy, and determine how often the pathogen had been introduced to the USA. A panel of 12 simple sequence repeat (SSR) markers identified 15 multilocus genotypes (MLGs) in a collection of 59 isolates from the USA (34 isolates), Myanmar (18), Taiwan (6) and Japan (1). Limited diversity in the USA isolates and the presence of one MAT idiotype (mating type locus) indicated that R. lauricola was probably introduced into the country a single time. MLG diversity was far greater in Asia than the USA. Only three closely related MLGs were detected in the USA, the most prevalent of which (30 of 34 isolates) was also found in Taiwan. Although more work is needed, the present results suggest that a Taiwanese origin is possible for the population of R. lauricola in the USA. Isolates of R. lauricola from Myanmar were distinct from those from Japan, Taiwan and the USA. Although both MAT idiotypes were present in Myanmar and Taiwan, only the population from Taiwan had the genetic structure of a sexually reproducing population.

scholarly journals Brood Production by Xyleborus glabratus in Bolts from Trees Infected and Uninfect ed with the Laurel Wilt Pathogen, Raffaelea lauricola

2018 ◽  
Author(s):  
Stephen W Fraedrich ◽  
Thomas C Harrington ◽  
Qiong Huang ◽  
Stanley J Zarnoch ◽  
James L Hanula ◽  
...  
Keyword(s):  
Laurel Wilt ◽  
Brood Production ◽  
Xyleborus Glabratus ◽  
Raffaelea Lauricola

scholarly journals First Report of Laurel Wilt, Caused by Raffaelea lauricola, on Spicebush (Lindera benzoin) in South Carolina

Plant Disease ◽  
2016 ◽  
Vol 100 (11) ◽  
pp. 2330 ◽  
Author(s):  
S. W. Fraedrich ◽  
T. C. Harrington ◽  
B. A. McDaniel ◽  
G. S. Best
Keyword(s):  
South Carolina ◽  
Laurel Wilt ◽  
First Report ◽  
Lindera Benzoin ◽  
Raffaelea Lauricola

scholarly journals First Report of Laurel Wilt Disease Caused by a Raffaelea sp. on Avocado in Florida

Plant Disease ◽  
2008 ◽  
Vol 92 (6) ◽  
pp. 976-976 ◽  
Author(s):  
A. E. Mayfield ◽  
J. A. Smith ◽  
M. Hughes ◽  
T. J. Dreaden
Keyword(s):  
South Carolina ◽  
Small Subunit ◽  
Persea Americana ◽  
Ambrosia Beetle ◽  
Sodium Hypochlorite Solution ◽  
Potential Threat ◽  
Laurel Wilt ◽  
Xyleborus Glabratus ◽  
Residential Neighborhood ◽  
Redbay Ambrosia Beetle

Laurel wilt is a vascular disease of redbay (Persea borbonia (L.) Spreng.) and other plants in the family Lauraceae in the southeastern United States. It is caused by a fungus (Raffaelea sp.) that is vectored by a non-native insect of Asian origin, the redbay ambrosia beetle (Xyleborus glabratus Eichhoff) (1). Since the initial detection of the redbay ambrosia beetle near Savannah, GA in 2002, laurel wilt has caused widespread mortality of redbay in Georgia, South Carolina, and Florida (1). In September 2007, an avocado (Persea americana Mill.) tree planted approximately 10 years earlier in a residential neighborhood in Jacksonville, FL was discovered to be infected with laurel wilt. The crown was in various stages of decline, including upper branches that were dead and leafless, those with wilted and drooping foliage, and those with healthy foliage. Removal of bark from wilted branch sections revealed black-to-brown streaks of discoloration in the sapwood and a few ambrosia beetle holes from which the discoloration extended into the adjacent wood. A Raffaelea sp. was isolated from discolored wood samples by surface sterilizing wood chips by submersion in a 5% sodium hypochlorite solution for 30 s and plating them on cycloheximide streptomycin malt agar (2). Small subunit (18S) sequences from the rDNA were amplified by PCR and sequenced with primers NS1 and NS4 (3). BLASTn searches revealed homology to Raffaelea sp. C2203 (GenBank Accession No. EU123076, 100% similarity, e-value of 0.0, and a total score of 1,886), which is known to be the causal agent of laurel wilt (1). The small-subunit rDNA sequence for this isolate has been deposited into GenBank and has been assigned accession No. EU257806. Pathogenicity of the laurel wilt pathogen on Persea spp. in growth chamber trials has been previously demonstrated (1). Laurel wilt is of concern to the commercial avocado industry and is a potential threat to the Lauraceae elsewhere in the Americas. References: (1) S. W. Fraedrich et al. Plant Dis. 92:215, 2008. (2) T. C. Harrington. Mycologia 73:1123, 1981. (3) T. J. White et al. Page 315 in: PCR Protocols, a Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, CA, 1990.

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