Cultural practices that improve biological control of black scale in olive orchards are more common in northern than southern California orchards. A parasite of black scale, recently imported from Spain, has become established in northern orchards and may in time aid in black scale control.

Funding for this research was provided by the California Olive Committee and the Division of Biological Control. The authors thank L. Ferguson, K, Hagen, C. Hill, C. Kennett, E. Kinsel, B. Krueger, M. Martin, F. Schiro, and S. Sibbett for assistance in project development and locating grower collaborators.