A Fungal Symbiont of the Redbay Ambrosia Beetle Causes a Lethal Wilt in Redbay and Other Lauraceae in the Southeastern United States

Abstract

2008. A fungal symbiont of the redbay ambrosia beetle causes a lethal wilt in redbay and other Lauraceae in the southeastern United States. Plant Dis. 92:215-224.

Exotic plant disease threats to the New Zealand avocado industry and climatic suitability: a review

“…Mortality was shown to have resulted from infestation by X. glabratus, followed by pathogenesis by the fungal pathogen R. lauricola (Fraedrich et al 2008). The insect vector was able to infest live plants of common sassafras, swamp bay (Persea palustris), camphor laurel, silk bay, gulf licaria (Licaria trianda), pondberry (Lindera melissifolia) and pondspice (Litsea aestivalis) which were then killed by the fungus (Fraedrich et al 2008;Smith et al 2009;Fraedrich et al 2011;Hughes et al 2011;Hughes et al 2012;Bates et al 2013;. Most members of the Lauraceae family that have been tested are susceptible to laurel wilt (Pena et al 2012).…”

“…The beetle carries fungal spores from tree-to-tree in specialised pouches called mycangia. The fungi multiply inside these mycangia in a yeast phase, nourished by secretions from surrounding gland cells (Fraedrich et al 2008;Harrington et al 2011).…”

“…Tree mortality has been reported (Freeman et al 2012), presumably of small trees. Fusarium euwallaceae survives in mycangia (small sacs) of the PSHB (Freeman et al 2012a), and, if similar to other fungi vectored by ambrosia beetles, is nurtured there in a yeast form by secretions from gland cells of the insect (Fraedrich et al 2008;Harrington et al 2011). The fungus also survives in infected plants within galleries made by the PSHB.…”

Destructive Tree Diseases Associated with Ambrosia and Bark Beetles: Black Swan Events in Tree Pathology?

“…Taleb (155) recognized such events in diverse fields including finance, history, science and technology. He suggested that black swan events: 1) have extreme impacts; 2) lie outside the realm of regular expectations (they are rare); and 3) are unpredictable.Although all ambrosia and bark beetle-associated diseases are not black swan events, several do fulfill the above criteria since they have large impacts, are uncommon surprises and are unpredictable (2,3,51,56,73,89,94,98,114,137,154,158, 164,165) (Table 1). They are typically understood and appreciated only with the benefit of hindsight and subsequent research.…”

“…These fungi usually colonize the lining or more substantial portions of natal galleries (14, 150), but typically do not cause disease. Thus, the phytopathogenicity of some of the symbionts is unexpected (51,89,114,120).When ambrosia beetle infestations are associated with serious damage, a wide range of interactions is evident. At one extreme are ambrosia beetles for which there is no clear involvement of the symbionts (6, 13, 99) (Table 1).…”