Ambrosia beetles of the Euwallacea fornicatus (Eichhoff, 1868) species complex are emerging tree pests, responsible for significant damage to orchards and ecosystems around the world. The species complex comprises seven described species, all of which are nearly identical. Given that the morphology-defined species boundaries have been ambiguous, historically, there has been much disagreement on species validity, which was compounded by the presumed loss of the type series of E. fornicatus. The species complex was recently reviewed using morphometrics to associate the type specimens to the clades delineated with molecular data under the assumption of the lost type series. We rediscovered a syntype of Xyleborus fornicatus, and reevaluated the species in the complex using morphometrics. We propose the following taxonomic changes to the species complex: Euwallacea fornicatus (=E. tapatapaoensis (Schedl, 1951); = E. whitfordiodendrus (Schedl, 1942)) syn. res.); E. fornicatior (Eggers, 1923) (=E. schultzei (Schedl, 1951) syn. nov.); E. kuroshio (Gomez and Hulcr, 2018) and E. perbrevis (Schedl, 1951) stat. res. These taxonomic changes shift the species name associated with the widely used common names for two taxa, namely: Euwallacea fornicatus should be used for the “Polyphagous Shot Hole Borer”, and E. perbrevis for the “Tea Shot Hole Borer clade a”. A lectotype is designated for X. fornicatus in order to stabilize the use of the name.

The present state of knowledge of the scolytine ambrosia beetles of Thailand is summarised to provide a basis for future studies of the fauna and its economic importance in forestry, timber production and crop tree plantations. A checklist of the fauna is provided with information on local and world distribution, host trees, biology and taxonomy. Six faunal elements based on geographical distribution, and the host tree and altitudinal preferences of species are discussed. One hundred and sixty-one species are recorded from Thailand, 67 of them for the first time. The following new synonym is proposed: Euwallacea wallacei (Blandford) (= Xyleborus barbatomorphus Schedl n.syn.). The following new combinations are given: Ambrosiophilus cristatulus (Schedl), Ambrosiophilus latisulcatus (Eggers), Beaverium dihingensis (Eggers), Beaverium lantanae (Eggers) and Immanus desectus (Eggers) are transferred from their present position in Ambrosiodmus; Ancipitis depressus (Eggers) and Ancipitis punctatissimus (Eichhoff) are transferred from Leptoxyleborus; Cyclorhipidion armipenne (Schedl), Cyclorhipidion inarmatum (Eggers), Euwallacea semiermis (Schedl), Fortiborus macropterus (Schedl), Microperus nudibrevis (Schedl) and Wallacellus minutus (Blandford) are transferred from Xyleborus.

Sarah M. Smith, Roger A. Beaver, and Anthony I. Cognato (2017) The Ambrosia Beetle Ambrosiophilus peregrinus Smith and Cognato, Introduced to the USA, is Ambrosiophilus nodulosus (Eggers), New Combination (Coleoptera: Curculionidae: Scolytinae) The Coleopterists Bulletin: Vol. 71, No. 3, pp. 552-553. https://doi.org/10.1649/0010-065X-71.3.552

In 2015, a trapping effort was initiated to collect individuals of the polyphagous shot hole borer, Euwallacea nr. fornicatus (Eichhoff), at five sites in northern Vietnam. The traps tested the usage of quercivorol (paramenthenol), a-copaene, cubeb oil, conophthorin, and ethanol as potential lures. These compounds have been effective in collecting individuals in the USA but have not been tested within the species' putative native range. As reported for the USA, the species responded best to the quercivorol lure. Throughout the duration of the study, 21 species were collected. Among them were Ambrosiophilus nodulosus (Eggers, 1941), Beaverium magnus (Niisima, 1910), new combination, Xyleborus glabratus Eichhoff, 1877, and Xylosandrus discolor (Blandford, 1898), all of which are new country records. Arixyleborus nudulus Smith, Rabaglia, and Cognato, new species, was also collected and is described and illustrated.

Ten species of ambrosia beetles of the tribe Xyleborini, Amasa beesoni (Eggers, 1930), Amasa opalescens (Schedl, 1937), Amasa cylindrotomica (Schedl, 1939), Arixyleborus hirsutulus Schedl, 1969, Beaverium latus (Eggers, 1923), Cnestus protensus (Eggers, 1930), Coptodryas quadricostata (Schedl, 1942), Cryptoxyleborus confusus Browne, 1950, Cryptoxyleborus percuneolus (Schedl, 1951) and Cyclorhipidion vigilans (Schedl, 1939), are recorded here for the first time in Thailand. Diagnostic characters, illustrations, distribution and biological data are provided for each species. Xylosandrus ramulorum (Schedl, 1957), stat. res. is removed from synonymy with Amasa cylindrotomica and reinstated as a valid species.

The four species currently placed in the genus Immanus Hulcr and Cognato are reviewed. Immanus papuanus Beaver, Sittichaya & Liu sp. n. is described. The following new synonymy is proposed: Immanus desectus (Eggers, 1923) (= Xyleborus insignis Browne, 1984 syn. n.). The following new combinations are proposed: Immanus pseudocolossus (Schedl, 1942) comb. n., I. sarawakensis (Eggers, 1923) comb. n., I. trolaki (Schedl, 1939) comb. n., all originally described in Xyleborus. A key to the females of the eight species now included in the genus is provided. The taxonomy, diagnostic characters, distribution and biology of the species are briefly discussed.