Obscure scale declines after parasitic wasp introduced

Abstract

Obscure scale, a pest of oak and pecan trees, was found in Sacramento's Capitol Park in 1962. By 1980 the scale was threatening the park's oaks. Red oaks seemed especially susceptible. In 1987–88 the imported parasite Encarsia aurantii was released to control the scale; the parasite's establishment was confirmed in 1990. By the end of 1996, scale infestations on both native and introduced oaks in the park were reduced to levels approaching complete biological control.