Developing a push-pull semiochemical pest management strategy for control of Ips grandicollis (Coleoptera: Curculionidae: Scolytinae) in pine plantations

Exotic pines (Pinus spp.) are planted commercially in Australia as a source of softwood timber used for sawlogs, engineered wood products, poles, girders, and pulp and paper. The bark beetle Ips grandicollis (Eichhoff) (Coleoptera: Curculionidae: Scolytinae) is a significant invasive pest of these softwood plantations, particularly when trees are stressed, during drought, or following fire. The beetle is native to eastern North America and spends much of its life within the phloem, or beneath the outer bark, of host trees, to which it transfers mutualistic fungi that block conductive tissue and cause blue staining, reducing the commercial value of the wood. Adult beetles use volatile semiochemicals as cues for host location and communication. For example, aggregation pheromones and host volatiles induce attraction (pull), whereas semiochemicals from competitor species and non-host plants may induce an avoidance (push) response. This thesis investigated the semiochemical-based push-pull technique as a potential eco-friendly management strategy for I. grandicollis, with the overarching goal of protecting Pinus trees and logs from beetle attacks.