The Risk of Bark and Ambrosia Beetles Associated with Imported Non-Coniferous Wood and Potential Horizontal Phytosanitary Measures

Abstract

Many bark and ambrosia beetle species (Coleoptera: Scolytinae and Platypodinae) are known to have spread worldwide in relation to international trade. Concerns have been expressed within the European and Mediterranean Plant Protection Organization (EPPO) about recent introductions of non-indigenous species of these groups. Regulation of the non-coniferous wood trade into many EPPO member countries is currently not sufficient to cover such risks. In 2018-2019, an EPPO study on the risk of bark and ambrosia beetles associated with imported non-coniferous wood was carried out, and the key characteristics contributing to the pest risk from introduced species were determined using expert consensus. This paper summarizes the key findings of the study, which are available in full detail on the EPPO website. The study identified biological and other risk factors and illustrated them with examples from 26 beetle species or groups of species known to be invasive or posing a threat to plant health. These representative species were classified into three categories based on known damage and level of uncertainty. In the present article, factorial discriminant analyses were used to identify features of bark and ambrosia beetle biology associated with damage caused and invasiveness. Based on the information assembled and consideration of the risk factors, it was recommended that in order to prevent the introduction of new bark and ambrosia beetles via non-coniferous wood commodities, horizontal phytosanitary measures should be adopted, irrespective of the host plant species and the origin (i.e., for all genera of non-coniferous woody plants and from all origins). Phytosanitary measures are presented here for various wood commodities.

What Determines Host Range and Reproductive Performance of an Invasive Ambrosia Beetle Euwallacea fornicatus; Lessons From Israel and California

“…There is no doubt that the PSHB attacks may cause tree mortality on certain host trees (Hulcr and Dunn, 2011;Mendel et al, 2017;Paap et al, 2018;Coleman et al, 2019). However, the concept of attacks on "healthy" trees is often debated in the literature, as trees that appear healthy may have been previously exposed to some stress (Grousset et al, 2020). Keler (1956) defined primary insects as "those which prefer completely healthy plants in full vigor"; based on this definition, Rudinsky (1962) suggested that most species of bark and ambrosia beetles must be considered secondary insects.…”

“…Although healthy trees are normally unsuitable to attack by bark and ambrosia beetles, some species are reported to attack and eventually kill live, apparently healthy non-coniferous trees, but this represents a minority of species to date (Grousset et al, 2020). Among the ambrosia-feeding scolytids, Xyleborini are the most numerous and widely distributed tribe.…”

TaqMan probe assays on different biological samples for the identification of three ambrosia beetle species, Xylosandrus compactus (Eichoff), X. crassiusculus (Motschulsky) and X. germanus (Blandford) (Coleoptera Curculionidae Scolytinae)

“…Scolytinae are xylophagous beetles colonizing the wood at phloem (phleophagous species) or xylem level (xylomycetophagous species) of many ornamental and forest plants (Kirkendall and Biedermann 2015 ). In recent years, Europe and the Americas have been affected by the introduction and establishment of numerous exotic species of the Xyleborini tribe, which caused growing concerns for native biodiversity and forest resources (Kirkendall and Faccoli 2010 ; Grousset et al 2020 ). Their ability to escape phytosanitary controls due to their cryptobiotic behaviour, their capacity to establish in the new environment due to their reproductive behavior, their large polyphagy and the increasing global trade of wood (Reed and Muzika 2010 ; Rassati et al 2016a ; Smith et al 2020 ) make Xyleborini a potentially invasive taxon.…”

Invasion of the Polyphagous Shot Hole Borer Beetle in South Africa A Preliminary Assessment of the Economic Impacts

“…In Somerset West in the Western Cape, PSHB spread at least 3 km from the putative point of introduction in only three months, and in the opposite direction of the prevailing winds (F Roets pers obs). Natural spread is therefore substantial, but the longdistance spread of PSHB is enabled by the ease of movement of infested wood and planting material (Grousset et al 2020). As a developing country, a large proportion of households in South Africa are heavily dependent on wood for their energy needs (Shackleton 2018), presenting a probable pathway for long-distance spread (Fig.…”