This is a document that has passed internal review. It is currently publicly available for interested stakeholders to provide feedback. The PRA may have some further updates depending on comments received.

This PRA covers four species of ambrosia beetle, which are a species complex, and their associated symbiotic fungi. The taxonomy of the beetles has been revised several times, but now appears to be approaching some stability, though there remains the possibility of 2 undescribed cryptic species within the current species delineation. New fungal species within the main symbiont group (the ambrosia Fusarium clade) are also still being isolated and described. All four beetle species are native to south and east Asia, and three have become pests outside their native range. Invasive populations have been found in several countries in the Americas, Hawaii, Israel and South Africa. There have also been outbreaks in Western Australia and mainland Europe which are being controlled by the relevant plant health authorities. These include glasshouse outbreaks, several of which have been successfully eradicated and one where eradication is ongoing. The beetles feed on a very wide range of hosts, mostly broadleaved woody species, but there have been a few records on other hosts such as palms, bamboo and conifers. They are all ambrosia beetles, meaning they create tunnels in wood and have symbiotic relationships with a range of fungal species in the ambrosia Fusarium clade and others. The fungi colonise the tunnels and feed on the wood, and the beetles feed on the fungus and not the host directly. Woody plants can be divided into three broad groups in terms of their suitability as hosts for E. fornicatus s.l. It should be noted that these categories are not fixed and some hosts assigned to one category are later found to belong to a different one. a) Reproductive hosts allow the symbiotic fungi to grow and the relevant beetle species to complete its entire lifecycle b) Non-reproductive hosts may be attacked by the beetle, fungal growth may occur, but these hosts do not allow the whole beetle lifecycle to be completed c) Plants not recorded as hosts have not showed evidence of beetle attack or, in some cases, may not allow the fungal symbiont to grow The scoring in this PRA is complex, as in some instances it was decided that ratings differ according to beetle species, but at other times the same rating was considered to apply to all four species.