Detection and sampling of emerald ash borer (Coleoptera: Buprestidae) infestations

Abstract

Emerald ash borer, Agrilus planipennis Fairmaire (EAB) (Coleoptera: Buprestidae), has caused devastating levels of mortality to ash trees ( Fraxinus Linnaeus, Oleaceae) in North America. Early infestations of this insect are extremely difficult to detect due to cryptic larval feeding and lack of obvious signs or symptoms of initial attack. Considerable research has been conducted to develop tools and techniques aimed towards providing early detection and delimitation of populations of this invasive species. Sampling tools and techniques include: (1) relating visual signs and symptoms to the presence of EAB infestations; (2) use of girdled trap-trees to increase captures of adults and subsequent larval densities; (3) sub-sampling protocols to detect larvae under the bark based on their within-tree distribution; (4) artificial traps baited with pheromones and/or host volatiles attractive to adult EAB; (5) biosurvellience using buprestid-hunting wasps; and (6) remote sensing techniques. Additional research modelling patterns of infestation at the landscape scale indicate very clumped or aggregated distributions, greatly increasing the difficulty of early detection across large spatial scales. Further research is still required to increase the efficacy and efficiency of early detection tools and techniques, including cost/benefit analysis of the various sampling options, increased understanding of patterns of initial infestation across the landscape, development of sampling programs for both detection and delimitation, and development of sequential sampling programs to estimate EAB density. This information will enable foresters to make informed decisions regarding management strategies against this devastating pest.