Efficiency of Japanese Beetle (Coleoptera: Scarabaeidae) Traps in Reducing Defoliation of Plants in the Urban Landscape and Effect on Larval Density in Turf

Abstract

Although attractant traps are commonly used to protect ornamental and garden plants from defoliation by Japanese beetles (Popillia japonica Newman), neither the utility of this practice nor its effect on larval density around traps has been investigated. In experiments on a golf course and in home landscapes, single traps positioned at 3.1 or 9.3 m upwind or downwind from test plants failed to reduce defoliation compared with that which occurred on plants without traps. In fact, defoliation was nearly always greater with a trap present. Surrounding a plant with three traps, each 9.3 m away, resulted in >90% defoliation within 30 h. Japanese beetle larval densities were not significantly altered in the vicinity of traps.