A native egg parasite, Trichogramma thalense, was mass-reared in the laboratory and released a maximum of thirteen times against the eggs of the artichoke plume moth (Platyptilia carduidactyla) in three 5-acre biointensive artichoke production fields on the northern Santa Cruz/San Mateo County coast in 1998 and again in 1999-2000. A biorational grower-managed pest management program for these fields (BIORAPP) was used in 1998 and included Trichogramma releases, pheromone-based mating disruption, double-cut control, and intensive monitoring of artichoke plume moth (APM) presence and artichoke damage. This program was monitored by a management team consisting of growers, an artichoke industry representative and a University researcher. Mass-released parasitoids were recovered from artichoke plume moth (APM) eggs collected post-release on only three dates, and in only one of the BIORAPP
fields, in 1998; however, APM egg deposition was low in all other fields. Parasitoids were not recovered from any of the three adjacent, 5-acre, non-release conventional artichoke fields.