Seasonal and Spatial Dispersal Patterns of Select Ambrosia Beetles (Coleoptera: Curculionidae) from Forest Habitats into Production Nurseries

Abstract

Exotic ambrosia beetles (Coleoptera: Curculionidae) are important pests of ornamental tree nurseries. Although these beetles reportedly disperse in early spring from peripheral forested areas into nurseries, few studies have determined how far they fly to infest new host trees, or whether a masstrapping strategy can adequately protect a nursery crop. Field monitoring with ethanol baits in South Carolina (2011-2012), Mississippi (2013 In addition to the well-documented spring flight peak, southeastern nursery managers may need to be aware of a second, late-summer flight. Captures from traps placed in a nursery at various distances (-25 to 200 m) from the forest-nursery interface showed a significant linear and quadratic trend in decreasing numbers of beetles captured with increasing distance from the forest in South Carolina, whereas significant linear, quadratic, and cubic trends were detected in Louisiana and Mississippi. Although captures at the nursery edge were lower than within the forest, traps placed at the nursery edge may still represent the optimal tool for both monitoring and mass-trapping programs because of easier access for personnel. Susceptible tree cultivars may gain added protection when placed deeper within nursery interiors and when baited traps line adjacent nursery edges.