Laurel Wilt Detected in Southeast Texas

Laurel wilt is a vascular disease caused by the fungus Raffaelea lauricola. It is transmitted by the invasive redbay ambrosia beetle (RAB), Xyleborus glabratus. The disease gets its name from its often deadly effects on members of the laurel family, including principally redbay, but also sassafras and avocado. The RAB was detected for the first time in Savannah, GA in spring 2002. Laurel wilt has subsequently been found in South Carolina, North Carolina, Mississippi, Alabama, Georgia, and notably in Florida, where commercial avocado groves are threatened. Large numbers of redbay, and to a lesser extent sassafras trees, of all diameters have been killed as the insect and disease complex has spread.

Unfortunately, this spring, redbay trees dying from laurel wilt fungus were detected by a U. S. Forest Service pathologist in Hardin County, Texas and the RAB was trapped in the same vicinity shortly thereafter. Currently, the disease has been found in southeast Texas only in Hardin and Jasper counties, but it may well be more widespread.

NOTE: A redbay ambrosia beetle was trapped the last week of June in Seicke State Forest in Newton County (Ron Billings, pers. com.).

"Signs and symptoms of laurel wilt are easy to recognize and include discolored foliage and staining of the sapwood (see pictures). Often, noodle-like exudations of sawdust are visible where the small ambrosia beetles penetrate the wood. Anyone observing dying or dead redbay or sassafras trees with these characteristics should notify the nearest Texas A&M Forest Service office or Regional Forest Health Specialist Allen Smith ( Avoid transporting the disease over long distances by not moving redbay firewood that may be infected. The fungicide propiconizole has shown some efficacy as a preventive measure for laurel wilt in redbay trees." Report observations of possible RAB using the “Report It!” function of

From the "Progress, Education, Science, Technology" (PEST) Quarterly Newsletter, June 2015 (Forest Pest Management Cooperative, Texas A&M Forest Service)

Learn more by reading the most current Laurel Wilt synopsis, or view the most recent map to see Laurel wilt’s history of spread. For more information on the RAB, see this link.

Laurel wilt epicormic branches

Laurel wilt stained wood
Red foliage and epicormics shoots on red bay (above), coupled with stained sapwood, are characteristic symptoms of infection by laurel wilt
Photo credit:  Ron Billings
A New Microsporidian is the First Described Pathogen of Tawny Crazy Ants

A step has been taken toward the biological control of tawny crazy ants (Nylanderia fulva). The Invasive Species Research group at the UT Austin Brackenridge Field Laboratory (BFL) and collaborating USDA scientists have described the first pathogen to be found in tawny crazy ants. The pathogen is a new genus of microsporidian parasites that infects the ant fat bodies. They are fascinating parasites because microsporidia, which are single-celled organisms, are among some of the simplest life forms, having evolved complex life histories including multiple spore types, yet have lost several key metabolic abilities and so have very small genomes. This new genus is additionally interesting because it is more closely related to microsporidian parasites of stoneflies than to microsporidia that infect other ant species. The new taxon is called "Myrmecomorba nylanderiae", which alludes to its being a pathogen of crazy ants (Nylanderia fulva).

The potential of this pathogen to be used for biological control of tawny crazy ants is the subject of ongoing studies in the BFL lab. Other microsporidia have been shown to have deleterious effects on their hosts, such as two species of microsporidia that infect fire ants. Long-term control of invasive ant populations will probably depend on a cocktail of host-specific pathogens and parasites.

Plowes, RM, JJ Becnel, EG LeBrun, DH Oi, SM Valles, NT Jones, LE Gilbert. (2015) Myrmecomorba nylanderiae gen. et sp. nov., a microsporidian parasite of the tawny crazy ant Nylanderia fulva. Journal of Invertebrate Pathology (129) 45–56

For more information on the tawny crazy ant, go here.

Nylanderia_pubens (tawny crazy ant)


Photographer: Bastiaan Drees, Texas A&M University
Invasive Spotlight:
Redbay Ambrosia Beetle
(Xyleborus glabratus)

The redbay ambrosia beetle (Xyleborus glabratus) is a dark colored, bullet shaped beetle with small puncture-like dents covering the elytra, and is 2 mm long when mature. The redbay ambrosia beetle can be identified with a characteristic snout representing modified mandibles for taking up nutrients. Positive identification of X. glabratus is almost impossible without the help of a professional, but the glaborous upper surface and abrupt apical declivity may help distinguish this invasive beetle from other native species. Redbay ambrosia beetle larvae are legless, white grubs with amber colored head capsules. These flightless grubs are found feeding on infected trees beneath or on the surface of the bark.

Originally from India, Japan, Myanmar, and Taiwan, the redbay ambrosia beetle is a known vector of the vascular fungus Raffaelea lauricola, which causes the host plant to wilt and die within a matter of months or even weeks. This insect-disease complex is referred to as laurel wilt in literature. Flight allows the beetle to transfer the fungus to new hosts rapidly. In 2002 the redbay ambrosia beetle was discovered near Port Wentworth, Georgia by chance in a survey trap. Within three years the beetle spread through the southeast U.S. and was associated with death to ambrosia and sassafras trees in Florida. Experts believe introduction of the redbay ambrosia beetle was facilitated by solid wood packing materials such as crates or pallets on which the beetle was feeding undetected. Found in FL, GA, MS, SC, and recently in Hardin and Jasper Counties, TX. In June of this year one was also detected in Newton Co., TX. (Note that the map to the right does not indicate all these locations yet.)

Follow this link to learn more about the redbay ambrosia beetle.

Redbay Ambrosia Beetle

Photographer: Michael Thomas
Source: Florida Department of Agriculture and Consumer Services,

RedbayAmbrosiaBeetle-map-final small

EDDMapS. 2015. Early Detection & Distribution Mapping System. The University of Georgia - Center for Invasive Species and Ecosystem Health. Available online at; last accessed July 31, 2015.


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If you would like your invasive species event or news listed in the next iWire, please send the details to

Sentinel Pest Network and Invaders of Texas Species Workshops

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For more information or to register to attend a workshop, please visit the Workshop Page.