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Timber-in-service consists of tree components prepared for use in building and carpentry and other wooden infrastructure such as bridges, pylons and power poles. About 70% of timber used in Australia goes into building and construction and 15-20% goes into furniture, and 50 000 electricity poles are produced annually. Timber-in-service pests are a threat to such material throughout its service life. In this review, we identify native and non-native insects associated with timber-in-service in Australia and their impacts and current management. Border and post-biosecurity interception data of insects associated with wood and wood products are analysed to assess future risks, and key biosecurity threats (i.e. exotic timber-in-service pests) are identified. We review current biosecurity systems and processes related to the mitigation of potential threats to timber-in-service and provide examples of how detections of exotic timber-in-service pests are managed in Australia. We conclude with recommendations on how to improve biosecurity and management of timber-in-service pests.

Bark beetles (Coleoptera: Curculionidae: Scolytinae) are among the most damaging tree pests globally. Rising temperatures, drought, fire, storms, cyclones, and poor forest management cause stress and loss of vigour in trees, and these conditions favour bark beetle outbreaks. While research has been conducted on push–pull strategies to deter bark beetles, using attractive and deterrent semiochemicals, the potential of this strategy to reduce bark beetle populations, particularly in the genera Dendroctonus and Ips, remains uncertain. Here, we conducted a global meta-analysis of 52 research articles to quantify the effects of semiochemical treatments on managing different species of Dendroctonus and Ips for forest protection. Based on this analysis, we found that push–pull semiochemicals can significantly reduce Dendroctonus and Ips populations measured by a reduction in the attraction to lure/trap catches, tree mortality, and attacks on trees. The overall efficacy of the push–pull semiochemical treatment shows a 66% reduction for Ips compared to control and a 54% reduction compared to control for Dendroctonus, while, at the species level, there was a 69% reduction for Dendroctonus ponderosae (Hopkins) and a 94% reduction in Ips perturbatus (Eichhoff), and a 93% reduction in Ips latidens (LeConte). Interestingly, among different treatment sources, the efficacy of conspecific semiochemicals in combination with heterospecific semiochemicals and non-host volatiles showed a 92% reduction in Dendroctonus spp., and conspecific semiochemicals in combination with non-host volatiles showed a 77% significant reduction in Ips spp., while the efficacy of heterospecific semiochemicals in reducing Ips population was about 69%, and 20% in Dendroctonus. Among different ecological regions, the use of a push–pull strategy showed a 70% reduction in Dendroctonus in central-west North America, and Ips showed a 75% reduction in southwest North America. Our results demonstrate that semiochem

We reviewed exotic insect species that are considered threats to Australia’s plantation, amenity, native forests and timber-in-service (“risk species”), comparing them to already-established non-native species. We examined biological and phylogenetic traits, border interceptions, origins and geographic distributions, to identify similarities between groups. Border interceptions of insect species considered an invasion risk were further analysed to identify their likely pathways. The two groups “risk species” and “established species” differed compositionally, with the dissimilarity possibly due to: (1) neither timber pests nor, to a lesser extent, exotic amenity tree host taxa being considered in industry or environmental biosecurity plans (e.g. explaining the under-representation of Bostrichidae in perceived risks compared to establishments and interceptions); (2) the importance of high-profile pests overseas (e.g. Monochamus spp., Lymantria spp.) inflating some groups over others; (3) unpredictability (“known unknowns”) (e.g. establishment of unexpected species such as Marchalina hellenica and Essigella californica); (4) identification of emerging pests or pathways that may differ from historical arrivals; (5) surveillance — for insects at least — traditionally targeting more detectable taxa (possibly explaining the over-representation of moths and cerambycids in risk lists compared to establishments). The under-representation of Hemiptera on risk lists may reflect their low visibility as impact species outside Australia, their lower detectability, and hence, unpredictability. Risk and established species groups could be separated based on body size and geographic distribution, as well as in the frequency (proportion of species intercepted), but not number, of border interceptions. Risk species were often intercepted from their invaded range, and were largely associated with wood products and packaging and non-commercial pathways (mail, baggage, personal effects).

The increased threat of pests and pathogens in plantations has strengthened the need to understand the factors underlying their occurrence, such as climate and tree ontogenic, and the effect of these pests and diseases on plant performance. Spotted gums (Corymbia citriodora and C. henryi), C. torelliana, and their hybrids are important commercial plantation taxa, because they are suited to a range of environments where traditional commercial eucalypts grow poorly. They have desirable field performance and can produce a range of timber and fibre products. This study investigated field performance, ontogenetic shifts from juvenile to intermediate leaves, and damage by pests and pathogens in pure spotted gum taxa, including C. citriodora subsp. citriodora (CCC), C. citriodora subsp. variegata (CCV) and C. henryi (CH), C. torelliana (CT), and their hybrids over a two year period. The study revealed that higher mean daily rainfall and maximum/minimum temperatures positively influenced tree performance but were also associated with higher levels of defoliation by generalist insects. Necrosis associated with Quambalaria pitereka was not correlated with climatic conditions in most of the taxa. Growth rate and defoliation were positively correlated, while flushing and damage parameters (defoliation and leaf necrosis) were often negatively correlated, suggesting that the taxa studied may have high tolerance to defoliation. Ontogenetic shifts were variable between taxa, occurring earlier in pure spotted gum taxa than in hybrids. The only environmental factor related to the transition from juvenile to intermediate leaves was mean daily rainfall, suggesting that ontogenetic shifts may be associated with an adaptation to water availability. Overall, CCC and CT × CCC displayed the best combination of performance and resistance to pests and pathogens. Severe defoliation was associated with reduced diameter at breast height over bark (DBH) in CCV and CH. Tree interactions with damag

Since outbreaks of the invasive blue gum chalcids Leptocybe spp. began, the genus Megastigmus (Hymenoptera: Megastigmidae) has been increasingly studied as containing potential biocontrol agents against these pests. Megastigmus species have been collected and described from Australia, the presumed origin of Leptocybe spp., with M. zvimendeli and M. lawsoni reported as Leptocybe spp. parasitoids established outside of Australia. Parasitic Megastigmus have been reported to occur locally in the Neotropics, Afrotropic, Palearctic, and Indomalaya biogeographic realms, and in many cases described as new to science. However, molecular tools have not been used in studying parasitic Megastigmus, and difficulties in morphological taxonomy have compromised further understanding of eucalypt-associated Megastigmus as well as the Megastigmus-Leptocybe association. In this study, we used molecular markers to study the species composition and phylogeny of Megastigmus collected from eucalypt galls in Australia and from Leptocybe spp. galls from South Africa, Kenya, Israel, China, and Vietnam. We record thirteen discrete species and a species complex associated with eucalypt galls. A summary of morphological characters is provided to assist morphological delimitation of the studied group. A phylogeny based on 28S rDNA identified species groups of importance to Leptocybe spp. biocontrol agents from four clades with nine species. Relationships between Megastigmus from eucalypt galls and their phytophagous congeners were unresolved. Further molecular work is needed to clarify the identity of many species.

The accidental introduction of the eucalypt-feeding paropsine beetle Paropsisterna cloelia (Paropsisterna variicollis) into New Zealand (NZ) in 2016 prompted investigation of the species complex to which the invasive species belongs. Two mitochondrial gene regions, Cytochrome c oxidase subunit 1 and Cytochrome b, were sequenced from field-collected specimens superficially resembling P. cloelia collected in Queensland, the Australian Capital Territory, New South Wales, Victoria, South Australia, Tasmania, Western Australia (WA) and NZ. Four distinct Paropsisterna species groups were found, and representatives from each clade were identified with named species using morphology. P. cloelia was confirmed via sequencing and morphology to occur in all sampled geographic regions. The WA and NZ populations showed no diversity at the gene regions studied and hence represent invasive populations. The invasive WA haplotype was shared with both Tasmania and Victoria, whereas the NZ haplotype was unique, but most similar to one shared between WA, Tasmania and Victoria. The melanistic colour variant of P. cloelia was only found in eastern mainland Australian populations and was absent from Tasmania and invasive populations. Implications for pest management, including biological control, are discussed.

Eucalypt forests and industrial plantations are threatened by fungal pathogen outbreaks that compromise timber and non-timber products and tree survival. Understanding host-pathogen interactions may contribute to the development of disease management strategies and the selection of resistant genotypes. Resistant and susceptible plants respond differently to disease infection, presenting variations of phenotypic traits, such as leaf physical and chemical parameters that may influence host-pathogen interactions. This study evaluated physical and chemical responses of Corymbia citriodora subsp. variegata to two fungal pathogens, Quambalaria pitereka (a co-evolved pathogen) and Austropuccinia psidii (an established exotic pathogen), using severity of infection as an indicator of plant resistance/susceptibility. Our primary aim was to quantify differential plant responses between uninoculated (controls), susceptible (severely infected) and resistant plants for each pathogen. Plant growth rate, leaf toughness and foliar secondary metabolite profiles of control, resistant and susceptible plants were compared 14 days after pathogen inoculations. Leaf secondary metabolite profiles were analysed from uninfected regrowth of the same plants 90 days after inoculation. The results indicated that only susceptible plants elicited responses to pathogen damage. Susceptible plants infected by Q. pitereka had greater leaf toughness, and susceptible plants infected by A. psidii had reduced growth rates and altered expression of secondary metabolites in comparison to control and resistant plants. Austropuccinia psidii infection led to a reduction in the proportion of monoterpenes and monounsaturated hydrocarbons and an increase in long chain hydrocarbons. No differences in secondary metabolite profiles were found between the treatments 90 days after inoculation, suggesting that differences observed were in response to severe infection and that leaf chemistry is not a good predictive biom

The genus Megastigmus Dalman, 1820 (Hymenoptera: Megastigmidae) contains potential biocontrol agents of the invasive eucalypt galling chalcid Leptocybe spp. (Hymenoptera: Eulophidae), with several species reported in various parts of the world. Species discrimination is challenging due to intraspecific morphological variation, difficulty in measuring sizes of body parts, and the lack of information regarding the global distribution of parasitic Megastigmus. We used two species commonly associated with Leptocybe in its native range to review taxonomic methods and determine the most reliable morphological characters in species delimitation. We examined size variation of body characters, and conducted species discrimination using multivariate ratio analysis, mitochondrial Cytochrome c oxidase subunit 1 (COI) and nuclear 28S rDNA (28S) sequences. Morphological traits were effective in species delimitation yet revealed high variation in several characters employed in current keys. Knowledge generated on morphology and DNA justified the description of a new species, M. manonae, sp. n., the first record of M. pretorianensis in Australia, and revised diagnostic characters for M. zvimendeli. Based on these diagnostic characters and molecular data, we synonymize three species (M. judikingae, syn. n., from Australia, M. sichuanensis, syn. n., from China and M. icipeensis, syn. n., from Kenya) with M. zvimendeli. Our findings highlight the importance of molecular markers in assisting taxonomic decision-making and the need for coordinated work in identifying Megastigmus associated with Leptocybe spp.