Non-native pests, climate change, and their interactions are likely to alter relationships between trees and tree-associated organisms with consequences for forest health. To understand and predict such changes, factors structuring tree-associated communities need to be determined. Here, we analysed the data consisting of records of insects and fungi collected from dormant twigs from 155 tree species at 51 botanical gardens or arboreta in 32 countries. Generalized dissimilarity models revealed similar relative importance of studied climatic, host-related and geographic factors on differences in tree-associated communities. Mean annual temperature, phylogenetic distance between hosts and geographic distance between locations were the major drivers of dissimilarities. The increasing importance of high temperatures on differences in studied communities indicate that climate change could affect tree-associated organisms directly and indirectly through host range shifts. Insect and fungal communities were more similar between closely related vs. distant hosts suggesting that host range shifts may facilitate the emergence of new pests. Moreover, dissimilarities among tree-associated communities increased with geographic distance indicating that human-mediated transport may serve as a pathway of the introductions of new pests. The results of this study highlight the need to limit the establishment of tree pests and increase the resilience of forest ecosystems to changes in climate.
Bursaphelenchus nematodes, extracted from 12 samples taken from imported packaging wood originating from seven countries and regions at Nanjing, China, during 2003 and 2004, were identified using morphology, morphometric data and ITS-RFLP patterns. Two samples were identified as B. xylophilus: one, from Canada, was the M-form and another, from Japan, the R-form. Five samples were identified as B. mucronatus, three belonging to the European genotype and two to the East-Asian genotype. Two samples (from Germany and South Korea) were recognised as B. rainulfi. Two samples (South Korea and Japan) were identified as B. doui and a sample from Hong Kong was identified as B. thailandae. Additional morphometric data are provided for the identified species, especially with respect to spicule morphometrics. The CDA of morphometric data discriminated the five species by nine male and eight female characters. The characters used for this analysis corresponded partly to the main taxonomic-informative characters for the genus Bursaphelenchus, viz., body length, stylet length, spicule length, a, c and c′ values. The phylogenetic trees constructed from the D2D3 sequence data supported the division of East Asian and European genotype groups of B. mucronatus. Bursaphelenchus doui grouped with B. xylophilus and B. mucronatus, all members of the xylophilus-group, which was separated from B. rainulfi and B. thailandae.
Using qualitative methods, this study assessed the stakeholders and management processes involved in locust outbreaks in China, including factors influencing the use of biopesticides. Study findings show that China has an integrated national locust response protocol, which involves various institutions from all administrative levels of the government. The process is inherently highly complex but efficient, with multisectoral agencies working closely together to prevent and/or manage locust outbreaks. In addition, the process has been successful in combating recent outbreaks, due to dedicated government funding, decisive administrative and technical actions, and the empowerment of local government administration. This is the case with the county level acting as a ‘first-responder’ that is capacitated financially and technically to respond to a locust invasion in their jurisdiction. Additionally, study findings show that despite the availability of biopesticides in local markets, their use is dampened by inadequate information about market availability, negative perceptions by decision makers about their efficacy, and concerns about their costs, as well as limited knowledge of their application techniques. Actions are therefore needed by relevant authorities to enhance stakeholder awareness of biopesticide market availability, efficacy, and field application processes. Future areas of research should focus on modelling the expected impact and cost effectiveness of chemicals vs. biopesticides, thus increasing the evidence base for promoting biopesticide use.
The Fall Armyworm, Spodoptera frugiperda, invaded China late in 2018 and was responsible for substantial crop losses, especially to maize. This work focuses on the suitability of climate across China for Fall Armyworm survival and spread. It uses climate metrics derived with guidance from experts to enable assessment of the risks posed by Fall Armyworm on maize production in different regions of China. The locations and time of year when temperature conditions are within a viable range for Fall Armyworm survival (minimum temperature higher than 9.7 $$^\circ$$ C and maximum temperature lower than 39.2 $$^\circ$$ C) are used to estimate the spatial distribution of winter breeding and overwintering zones, which helps understand the regions and timing of Fall Armyworm migration risk into northern maize production regions. In addition, meridional wind conditions across the Yangtze River basin area are assessed, and a metric of migration potential from the winter breeding and overwintering regions in the south towards northern regions with maize production is established. Results show that temperature during the winter months currently limits Fall Armyworm winter breeding populations to the very southern regions of China (and bordering countries to the south). However, due to the consistent timing and direction of the East Asian Summer Monsoon winds, the Fall Armyworm could easily be directed northwards to the Yangtze River basin during summer months with a peak in July. For this reason, pest management actions against the Fall Armyworm on summer maize should be taken.