Biological invasions are among the most serious threats to native forest
ecosystems worldwide due to ever-increasing global trade and climate
change. Understanding invasion processes and the ecology of invasive
pests in both newly invaded and native habitats is necessary to
effectively mitigate and manage the risks they pose. The effects of
exotic ash tree species planted from 1900 to 2019 on distribution,
occurrence, and outbreak frequency of a native pest emerald ash borer,
Agrilus planipennis Fairmaire, were examined. The frequency and level of
pest infestations gradually increased following introduction and
widespread plantings of non-native host trees, and the first recorded
outbreak occurred after a time lag of 30-50 years. Increased pest
populations enhanced its invasion risk to other regions including the
native ranges of introduced plants.