Disentangling the drivers of invasion spread in a vector-borne tree disease

Long-term survey of longhorn beetles revealed changes in faunal features in Ito on the Izu peninsula

Long-term biodiversity monitoring is essential for unveiling the impact of environmental changes on local fauna. Although private local records can contribute significantly to biodiversity evaluation, they are seldom published in scientific journals. In this study, a retired scientist recorded the longhorn beetles (Distiniidae and Cerambycidae) present in Ito on the Izu peninsula, Japan, for 12 years. The records showed the dynamical changes in longhorn beetles, which indicated the environmental changes around the survey site over 12 years. We also compared the longhorn beetle composition in the Ito study site to those in the survey records in 13 other locations in Kanto, Japan. We found that the species composition in Ito was stable throughout the 12 years, while the general composition in Ito reflected the land-use pattern of urban areas and the collecting methods. The species composition in the Ito study site differed from that in some of the other satoyama locations (human-influenced natural environment), but this was possibly due to methodological differences. Long-term backyard biodiversity surveys, especially those conducted by retired professionals, can play important roles in future investigations of insect groups, such as longhorn beetles, even if they are not agricultural pests nor endangered species.

The Epidemiology of Plant Virus Disease: Towards a New Synthesis

Epidemiology is the science of how disease develops in populations, with applications in human, animal and plant diseases. For plant diseases, epidemiology has developed as a quantitative science with the aims of describing, understanding and predicting epidemics, and intervening to mitigate their consequences in plant populations. Although the central focus of epidemiology is at the population level, it is often necessary to recognise the system hierarchies present by scaling down to the individual plant/cellular level and scaling up to the community/landscape level. This is particularly important for diseases caused by plant viruses, which in most cases are transmitted by arthropod vectors. This leads to range of virus-plant, virus-vector and vector-plant interactions giving a distinctive character to plant virus epidemiology (whilst recognising that some fungal, oomycete and bacterial pathogens are also vector-borne). These interactions have epidemiological, ecological and evolutionary consequences with implications for agronomic practices, pest and disease management, host resistance deployment, and the health of wild plant communities. Over the last two decades, there have been attempts to bring together these differing standpoints into a new synthesis, although this is more apparent for evolutionary and ecological approaches, perhaps reflecting the greater emphasis on shorter often annual time scales in epidemiological studies. It is argued here that incorporating an epidemiological perspective, specifically quantitative, into this developing synthesis will lead to new directions in plant virus research and disease management. This synthesis can serve to further consolidate and transform epidemiology as a key element in plant virus research.

Pest categorisation of non-EU Monochamus spp

The Panel on Plant Health performed a pest categorisation of non‐EU Monochamus spp., a well‐defined insect genus in the family Cerambycidae (Insecta: Coleoptera). Species can be identified using taxonomic keys at national and regional level, and DNA barcoding. Two online world catalogues exist for the genus. The genus includes about one hundred species and many subspecies colonising conifers and non‐conifer trees in many areas in the world. The non‐EU species are listed in Annex IAI of Council Directive 2000/29/EC. Although Monochamus spp. colonise weakened or dead trees and have therefore no direct impact, some species vector the pine wood nematode, Bursaphelenchus xylophilus, which they inoculate to healthy trees when they proceed to maturation feeding on twigs, causing high mortality among pines in Asia and the EU (Portugal). Sixteen species in Asia and America attack conifers. The main pathways for entry are raw untreated wood and wood products, wood packaging material, particle wood and waste wood, finished wood products and hitchhiking. Monochamus species were categorised in two groups. The first group includes 16 species colonising conifers and absent in the EU known or likely to vector the pine wood nematode. The species in this group satisfy all the criteria to be considered as Union quarantine pests. Measures are in place to prevent the introduction of Monochamus with coniferous wood. The second group gathers all the remaining species, all non‐EU species colonising non‐conifers. These do not satisfy all the criteria to be considered as Union quarantine pests. As plants for planting are not a pathway for Monochamus spp., and as most of the species within these groups are absent from the EU territory, the two groups do not meet the criteria to be considered as regulated non‐quarantine pests.