As part of national biosecurity programs, cargo imports, passenger baggage, and international mail are inspected at ports of entry to verify compliance with phytosanitary regulations and to intercept potentially damaging nonnative species to prevent their introduction. Detection of organisms during inspections may also provide crucial information about the species composition and relative arrival rates in invasion pathways that can inform the implementation of other biosecurity practices such as quarantines and surveillance. In most regions, insects are the main taxonomic group encountered during inspections. We gathered insect interception data from nine world regions collected from 1995 to 2019 to compare the composition of species arriving at ports in these regions. Collectively, 8,716 insect species were intercepted in these regions over the last 25 yr, with the combined international data set comprising 1,899,573 interception events, of which 863,972 were identified to species level. Rarefaction analysis indicated that interceptions comprise only a small fraction of species present in invasion pathways. Despite differences in inspection methodologies, as well as differences in the composition of import source regions and imported commodities, we found strong positive correlations in species interception frequencies between regions, particularly within the Hemiptera and Thysanoptera. There were also significant differences in species frequencies among insects intercepted in different regions. Nevertheless, integrating interception data among multiple regions would be valuable for estimating invasion risks for insect species with high likelihoods of introduction as well as for identifying rare but potentially damaging species.

The economic and environmental threats posed by non-native forest insects are ever increasing with the continuing globalization of trade and travel; thus, the need for mitigation through effective biosecurity is greater than ever. However, despite decades of research and implementation of preborder, border, and postborder preventative measures, insect invasions continue to occur, with no evidence of saturation, and are even predicted to accelerate. In this article, we review biosecurity measures used to mitigate the arrival, establishment, spread, and impacts of non-native forest insects and possible impediments to the successful implementation of these measures. Biosecurity successes are likely under-recognized because they are difficult to detect and quantify, whereas failures are more evident in the continued establishment of additional non-native species. There are limitations in existing biosecurity systems at global and country scales (for example, inspecting all imports is impossible, no phytosanitary measures are perfect, knownunknowns cannot be regulated against, and noncompliance is an ongoing problem). Biosecurity should be a shared responsibility across countries, governments, stakeholders, and individuals.

Assessing exotic pest response and eradication programs can identify factors that will lead to increased pest detection and provide information for prioritizing and enhancing future eradication attempts. We review the forest-related insect and pathogen detections and responses in Australia between 1996 and 2017. Thirty-four detections of new exotic forest species were made in this timeframe; seventeen each of insects and pathogens. Twenty-nine of the species are now established in mainland Australia and another in the Torres Strait. Four of the established species cause high impact, and three of these were subject to failed eradication programs. Two of the four established high-impact species were not previously recognised as threats; indeed, 85% of all new detections were not considered high-priority risks. Only one forest pest has been successfully eradicated, suggesting a lower success rate of Australian forest eradication programs than the world average. Most of these exotic pests and pathogens were not detected early enough to attempt eradication, or they were not deemed a significant enough pest to warrant an eradication attempt. Early detection is key to successful eradication. We discuss current surveillance programs in Australia and the methods (general, specific), locations (urban, regional, amenity, plantation, nursery, native forest), and surveillance type (public, industry, ad-hoc researcher, forest health surveillance, high-risk site surveillance, pest-specific trapping) that detections were made under. While there has been an increase in detections using specific surveillance since 2010, there remains a need for a structured national approach to forest biosecurity surveillance, preparedness, and responses.

Geographic isolation, unique native flora, and a robust biosecurity system have resulted in Australia remaining free from many of the devastating exotic pests found in other countries. Nevertheless, at least 260 non-native arthropods and pathogens of forest hosts have established in Australia since 1885. Although the risk of invasive species arriving and establishing in Australia is increasing through raised levels of trade and travel, the rate of establishment of non-native forest pests has remained relatively constant over the last 130 years, accumulating at a rate of about two per year. The majority of these are arthropods and pathogens of tree host genera exotic to Australia, including the main plantation species, Pinus radiata; few are significant pests of tree host genera native to Australia. Eighteen percent of these pests have caused moderate to significant impact or resulted in ongoing management costs in commercial plantations, native forests, or amenity trees. Asian and European species accounted for two-thirds of Australia’s non-native forest pests, and were equivalently represented numerically, temporally, and compositionally. Asian species were more polyphagous and more frequently established in northern Australia, possibly reflecting climatic similarity, geographic proximity, and host plant suitability. Earlier-establishing species were more polyphagous and had broader Australian and global non-native distributions. We here provide the first comprehensive database of non-native arthropod and pathogen species of relevance to Australia’s plantation, amenity, and native forest trees in Australia. This knowledge will assist with identifying key traits of exotic pest threats to forests in Australia and globally to inform national and international biosecurity policy.