Dispersal Patterns of Ambrosia Beetles (Coleoptera: Curculionidae: Scolytinae) from Peripheral Habitats into Tree Nurseries

Exotic ambrosia beetles (Coleoptera: Curculionidae) present a serious challenge to cost-effective nursery production.  While ambrosia beetles are known to migrate in early spring from peripheral forested areas into nurseries, there is little data to show how far they will fly to infest new host trees, or whether a mass trapping strategy can adequately protect a nursery crop.  From 2013-14, field tests were performed in Mississippi and Louisiana to determine timing of peak ambrosia beetle flight, dispersal distance and optimal location of ethanol-baited traps.  In addition to the well-documented spring peak, southeastern nurseries need to be aware of a second, serotinal flight.  Captures from traps placed at eight different distances from the forest/nursery interface were significantly different, with a density-decay effect observed with increasing distance from the forest.  While captures at the nursery edge were lower than within the forest, edge traps may still represent the optimal position for both monitoring and mass-trapping programs.  Susceptible tree cultivars may gain additional protection by being located within nursery interiors, particularly when maintaining a row of baited traps along the nursery edge.