Abundance of Beneficial Arthropods on Woody Landscape Plants at Professionally-Managed Landscape Sites

Abstract

Abstract Eight 0.2–0.4 ha (0.5–1.0 A) sites managed by landscape professionals were monitored biweekly for beneficial arthropod activity. More than 30 generalist predator taxa were identified. Spiders and green lacewings were the most numerous taxa and both were found on all plant taxa sampled. Green lacewings, especially the egg stage, were the most numerous natural enemies detected on birch, crape myrtle, cherry, and oak trees accounting for 52.5, 49.9, 43.5, and 38.1%, respectively. Spiders accounted for 56.2% of the insectivorous arthropods observed on magnolia and were the most abundant predatory arthropod on azaleas comprising 46.5% of all arthropod predators/parasites across all properties. The most abundant predatory arthropods on junipers were spiders accounting for 75.5% of the beneficials encountered with ants (associated with an early season aphid outbreak), green lacewing larvae, lady beetles, harvestmen, and parasitic wasps comprising 15.8, 0.4, 4.3, 0.4, and 1.2%, respectively. Spiders were the most abundant predators on boxwood accounting for 70.6% of the natural enemies.