Biological control of the olive scale—Parlatoria oleae (Colvée)—by a parasitic wasp imported to California, showed marked improvement in 1960 over 1956, when a previous survey was made.

Photographs by F. E. Skinner, Laboratory Technician, Department of Biological Control, University of California, Berkeley.

A. M. Boyce, Dean of the College of Agriculture, Riverside, imported the original stock of the Persian wasp from Iram and Iraq in 1951.

R. L. Doutt, Associate Professor of Biological Control, University of California, Berkeley, initiated the program of colonization in 1952.

G. L. Finney, Associate Specialist in Biological Control, University of California, Berkeley, and his associates propagated the colonization stock for the distribution program in the University Insectary.

The California State Department of Agriculture, County Agricultural Commissioners and County Farm Advisors of the University of California Extension Service assisted in the distribution and release of the parasitic wasp in scale infested olive orchards.