Using a botanical garden to assess factors influencing the colonization of exotic woody plants by phyllophagous insects

Insect wood borers on commercial North American tree species growing in China: review of Chinese peer-review and grey literature

Invasive insect wood borers are a threat to global forests and tree-related industries as they can damage trees and spread plant pathogens. Reports of damages by wood borers on plants that were planted overseas may facilitate the identification of potential invaders and speed up risk assessment. However, much of this information remains unavailable to the international plant protection community due to language barriers, lack of digitization, or limited circulation of regional literature. Here, we investigated reports of wood borers on 7 important North American commercial tree species planted in China (Carya illinoinensis, Liquidambar styraciflua, Pinus elliottii, Pinus taeda, Quercus texana, Quercus rubra, and Quercus virginiana) in peer-reviewed as well as "grey" (nonpeer-reviewed) Chinese literature. A total of 60 unique wood borer records were found, yielding reports of 4 orders, 39 genera, and 44 species of insect wood borers. Among Coleoptera, longhorned beetles (Cerambycidae) were the most commonly reported colonizers of North American trees in China. Chinese peer-reviewed reports of pests on alien plants are a valuable tool to survey for potential wood-boring invaders of North America, and wherever North American trees are planted and have the potential to encounter Asian invasive insects. Digitization and dissemination of non-English literature are essential for contemporary risk assessment. On the other hand, the nonpeer reviewed "grey" literature, primarily agency reports and student theses, provided only 5% of the records; many incidental observations were unreliable.

Towards a global sentinel plants research strategy to prevent new introductions of non-native pests and pathogens in forests. The experience of HOMED

The use of sentinel woody plants in experimental plantings, Botanical Gardens and Arboreta has been experimentally validated as a tool for identifying possible unknown future threats prior to their introduction into new countries. Sentinel Plantings were recently established in Italy, France, Switzerland, China and South Africa, using a common experimental design. The plantings included various tree and shrub species of broadleaves and conifers. Two planting types were established, each with different objectives. In-patria plantings using native plants aim to estimate, in absence of any phytosanitary treatments, the associations and infestation rates of native insects susceptible to be exported to other countries with that particular commodity. Ex-patria plantings using non-native plants are relevant to identify native insect species capable of switching to the non-native plant that would otherwise be impossible to predict prior to its introduction. In the frame of the EU project HOMED, we have implemented this concept, widening the use of this tool simultaneously to many different countries and continents

Citizen science can enhance strategies to detect and manage invasive forest pests and pathogens

Incorporating a citizen science approach into biological invasion management strategies can enhance biosecurity. Many citizen science projects exist to strengthen the management of forest pest and pathogen invasions within both pre- and post-border scenarios. Besides the value of citizen science initiatives for early detection and monitoring, they also contribute widely to raising awareness, informing decisions about eradication and containment efforts to minimize pest and pathogen spread, and even finding resistant plant material for restoration of landscapes degraded by disease. Overall, many projects actively engage citizens in the different stages of forest pest and pathogen invasions, but it is unclear how they work together across all stages of the entire biological invasion process to enhance biosecurity. Here we provide examples of citizen science projects for each stage of the biological invasion process, discuss options for developing a citizen science program to enhance biosecurity, and suggest approaches for integrating citizen science into biosecurity measures to help safeguard forest resources in the future.

An intercontinental comparison of insect seed predation between introduced and native oaks

Novel interactions between introduced oaks and their natural enemies across different continents provide an opportunity to test the enemy release hypothesis (ERH) at local and global scales. Based on the ERH, we assessed the impacts of native seed-feeding insects on introduced and native oaks within and among continents. We combined a common-garden experiment in China and biogeographic literature surveys to measure seed predation by insects and the proportion of acorn embryos surviving after insect infestation among 4 oak species with different geographical origins: Quercus mongolica origin from China, Q. robur and Q. petraea from Europe, and Q. rubra from North America. Mostly supporting the ERH, oaks in introduced continents escaped seed predation compared to those in native continents and compared to other native oaks in introduced continents. Common-garden comparisons showed that total acorn infestation rate of introduced Q. rubra (section Lobatae) was considerably lower than that of native oaks (section Quercus) in China and Europe, likely because of the differences in seed traits associated with different oak sections. Literature surveys showed that seed predation of introduced oaks was lower in the introduced continent than in the native continent. Embryo survival was higher in introduced Q. rubra than native oaks in China and Poland. However, insect seed predation of recently introduced Q. rubra in China was similar to that in Europe, which is not consistent with the ERH. Our results suggest that reduced acorn attack by native insects and higher embryo survival after acorn damage could increase the establishment success or invasion risk of introduced oaks in non-native continents.

Effects of vegetation management on the composition and diversity of the insect community at Tianjin Binhai International Airport, China

The vegetation community affects the composition and diversity of the insect community in grasslands. To explore the effects of vegetation management on insect community abundance and diversity, regular mowing of the vegetation was conducted, and tall fescue (Festuca arundinacea) and ryegrass (Lolium perenne) were exclusively planted at Tianjin Binhai International Airport. A total of 1886 insects were collected, representing 8 orders, 23 families, and 29 species; Acrididae (Orthoptera), Coccinellidae (Coleoptera), and Chironomidae (Diptera) were the dominant taxa. The abundance and biomass of insects in the turf areas were significantly lower than those in the control area and were reduced by 45.8 and 48.5% in the ryegrass area, respectively. In all areas, insect abundance and biomass peaked in summer, and the abundance of individuals and taxa decreased as the temperature decreased. Greater diversity and richness were found in summer compared with the other two seasons, and the turf areas had lower diversity and richness indices than the control areas in spring and summer. Our results suggest that the abundance, biomass and diversity of insects can be effectively decreased by artificial regulation of grassland vegetation at the airport, the planting of a single turfgrass - specifically ryegrass had the greatest effect. The present study provides a theoretical basis for the ecological control of insects at the airport.

Introduced plants as novel Anthropocene habitats for insects

Major environmental changes in the history of life on Earth have given rise to novel habitats, which gradually accumulate species. Human-induced change is no exception, yet the rules governing species accumulation in anthropogenic habitats are not fully developed. Here we propose that nonnative plants introduced to Great Britain may function as analogues of novel anthropogenic habitats for insects and mites, analysing a combination of local-scale experimental plot data and geographic-scale data contained within the Great Britain Database of Insects and their Food Plants. We find that novel plant habitats accumulate the greatest diversity of insect taxa when they are widespread and show some resemblance to plant habitats which have been present historically (based on the relatedness between native and nonnative plant species), with insect generalists colonizing from a wider range of sources. Despite reduced per-plant diversity, nonnative plants can support distinctive insect communities, sometimes including insect taxa that are otherwise rare or absent. Thus, novel plant habitats may contribute to, and potentially maintain, broader-scale (assemblage) diversity in regions that contain mixtures of long-standing and novel plant habitats.

The value of sentinel plants for risk assessment and surveillance to support biosecurity

Effective surveillance for early detection of invasive alien species in natural ecosystems, or on valued plants found in modified areas, could prevent potentially devastating and costly impacts (whether environmental, economic or cultural) of new invasions on the invaded country. Surveillance technologies are often constrained by a range of factors. Determining which species present a significant risk before they reach the border is an effective strategy to minimize the possibility of invasion and/or the impact of invasion. Surveillance of sentinel plants provides an important tool to strengthen biosecurity programs assisting with i) detecting and identifying insect pests, nematodes and plant diseases that could potentially invade uncolonized countries, and ii) developing pest risk analysis profiles to eliminate or mitigate the risk of arrival. This review examines some of the challenges and opportunities provided by sentinel plant research and discusses the factors that could affect the success of their use for biosecurity risk assessment and surveillance in the New Zealand context.

Forewarned is forearmed: harmonized approaches for early detection of potentially invasive pests and pathogens in sentinel plantings

The number of invasive alien pest and pathogen species affecting ecosystem functioning, human health and economies has increased dramatically over the last decades. Discoveries of invasive pests and pathogens previously unknown to science or with unknown host associations yet damaging on novel hosts highlights the necessity of developing novel tools to predict their appearance in hitherto naïve environments. The use of sentinel plant systems is a promising tool to improve the detection of pests and pathogens before introduction and to provide valuable information for the development of preventative measures to minimize economic or environmental impacts. Though sentinel plantings have been established and studied during the last decade, there still remains a great need for guidance on which tools and protocols to put into practice in order to make assessments accurate and reliable. The sampling and diagnostic protocols chosen should enable as much information as possible about potential damaging agents and species identification. Consistency and comparison of results are based on the adoption of common procedures for sampling design and sample processing. In this paper, we suggest harmonized procedures that should be used in sentinel planting surveys for effective sampling and identification of potential pests and pathogens. We also review the benefits and limitations of various diagnostic methods for early detection in sentinel systems, and the feasibility of the results obtained supporting National Plant Protection Organizations in pest and commodity risk analysis.