The olive scale, Parlatoria oleae, was first found in California in 1934 and has since become a major pest. Attempts to control this insect by biological means began with the introduction of the external parasite, Aphytis maculicornis, from Iran in 1952. Inconsistent control by A. maculicornis led to the introduction of two additional parasites from Pakistan in 1957. One of these, Coccophagoides utilis, became established in California.

Coccophagoides utilis is an internal parasite which attacks both scale generations which P. oleae produces each year. Adult female C. utilis which have been mated deposit female eggs only. Unmated females deposit male eggs only. Field results show C. utilis capable of destroying up to 50 per cent of each host generation. The two species of parasites working together have exhibited the ability to give excellent control of olive scale.