Emergence suppression of bark and ambrosia beetles in infested oaks

Abstract

Logs were cut from each of eight coast live oaks (Quercus agrifolia) and one California black oak (Q. kelloggii) infested with bark and ambrosia beetles. For each tree, one log was collected from 1 m (3.3 ft) above the ground, a second from immediately below the crotch of the major limbs, and a third from a branch 8 cm (3 in.) in diameter. Permethrin significantly reduced emergence of both oak ambrosia beetles (Monothrum scutellare) and oak bark beetles (Pseudopityphthorus pubipennis) from the insecticide-treated logs (P = 0.001) compared to the control log sections. This result indicates the bark application of permethrin can lower the density of bark and ambrosia beetles in urban forests.