The Fungus Raffaelea lauricola Modifies Behavior of Its Symbiont and Vector, the Redbay Ambrosia Beetle (Xyleborus Glabratus), by Altering Host Plant Volatile Production

This review highlights current advances in the management of the redbay ambrosia beetle, Xyleborus glabratus, a primary vector of the pathogenic fungus, Raffaelea lauricola, that causes laurel wilt. Laurel wilt has a detrimental effect on forest ecosystems of southeastern USA, with hundreds of millions of Lauraceae deaths. Currently, preventive measures mostly focus on infected-tree removal to potentially reduce local beetle populations and/or use of preventative fungicide applications in urban trees. Use of semiochemicals may offer an opportunity for the management of X. glabratus. Research on attractants has led to the development of α-copaene lures that are now the accepted standards for X. glabratus sampling. Research conducted on repellents first included methyl salicylate and verbenone and attained significant reduction in the number of X. glabratus captured on redbay and swamp bay trees treated with verbenone. However, the death rate of trees protected with verbenone, while lower compared to untreated trees, is still high. This work underscores the necessity of developing new control methods, including the integration of repellents and attractants into a single push-pull system.

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

Phytopathology ◽

10.1094/phyto-01-10-0032 ◽

2010 ◽

Vol 100 (10) ◽

pp. 1118-1123 ◽

Cited By ~ 40

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.

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Efficacy of current lures for detection of redbay ambrosia beetle,Xyleborus glabratus(Coleoptera: Curculionidae: Scolytinae)

10.1603/ice.2016.113552 ◽

2016 ◽

Author(s):

Paul E. Kendra

Keyword(s):

Ambrosia Beetle ◽

Xyleborus Glabratus ◽

Redbay Ambrosia Beetle

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Eucalyptol is an Attractant of the Redbay Ambrosia Beetle, Xyleborus Glabratus

Journal of Chemical Ecology ◽

10.1007/s10886-014-0427-z ◽

2014 ◽

Vol 40 (4) ◽

pp. 355-362 ◽

Cited By ~ 20

Author(s):

Emily H. Kuhns ◽

Xavier Martini ◽

Yolani Tribuiani ◽

Monique Coy ◽

Christopher Gibbard ◽

...

Keyword(s):

Ambrosia Beetle ◽

Xyleborus Glabratus ◽

Redbay Ambrosia Beetle

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Role of host plant volatile in the host-finding behavior of the strawberry leaf beetle, Galerucella vittaticollis Baly (Coleoptera: Chrysomelidae)

Applied Entomology and Zoology ◽

10.1303/aez.2006.357 ◽

2006 ◽

Vol 41 (2) ◽

pp. 357-363 ◽

Cited By ~ 19

Author(s):

Masatoshi Hori ◽

Kazuya Ohuchi ◽

Kazuhiro Matsuda

Keyword(s):

Host Plant ◽

Leaf Beetle ◽

Host Finding ◽

Host Plant Volatile ◽

Plant Volatile ◽

Host Finding Behavior

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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 ◽

10.3390/f10010037 ◽

2019 ◽

Vol 10 (1) ◽

pp. 37 ◽

Cited By ~ 4

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.

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