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Two breeding populations of the non-native Asian longhorned beetle (Anoplophora glabripennis Motschulsky), a pest of broadleaf trees in its native China, were discovered in Ontario in 2003 and 2013, respectively. Both populations were eradicated by removing all trees injured by the beetle and all uninjured trees deemed at high risk of injury. We used data collected during this removal to study host selection. Signs of A. glabripennis injury were observed on 732 stems from seven (i.e., Acer, Salix, Populus, Betula, Ulmus, Fraxinus, and Tilia) of the 45 tree genera available. Complete beetle development was confirmed on only the first four of these seven genera. Most signs of injury were on the genus Acer and on trees with a diameter at 130 cm above ground ranging between 15 and 40 cm. On most trees, the lowest sign of injury was within 3 m of the ground or within 40% of tree height. Tree height explained 63% of the variance in the location of the lowest sign of injury. Initial attacks were typically near the middle of the tree and expanded both upward and downward with successive attacks over time. We discuss how these findings could improve survey efforts for A. glabripennis. [ABSTRACT FROM AUTHOR]

1. Competition and predation are important components of biotic resistance, which helps define the invasibility of an ecosystem. 2. To search for evidence of biotic resistance to the European woodwasp, Sirex noctilio Fabricius, in North America, cages were used to experimentally exclude the community of associates (natural enemies and competitors) from infested logs. Specifically, the study assessed S. noctilio brood production in pine forests in Ontario and New York, where there was a rich existing community of associates (other wood borers, bark beetles and associated fungi, and parasitoids), and in South Africa, where siricid wasps and pines are not native and a similar associate community is not present. In addition, in Ontario, associates were excluded by size, and for different periods of time to identify important associates and their temporal dynamics. 3. Evidence was found that biotic factors limit S. noctilio in North America, whereby exclusion of natural enemies and competitors had a positive influence on the abundance or presence of S. noctilio brood in Ontario and New York. This influence was absent in South Africa. 4. It is unclear which member(s) of the associated insect community in North America were most important in limiting S. noctilio brood production, although they probably acted quickly (< 2 weeks) following S. noctilio oviposition. 5. Further study is needed to determine whether associates have limited S. noctilio populations in pine forests throughout northeastern North America, and which specific natural enemies and/or competitors are important. [ABSTRACT FROM AUTHOR]