Dispersal of the egg parasitoid Trissolcus basalis (Hymenoptera:Scelionidae) in tomato

Three experiments were conducted in Charleston, South Carolina, during 1993 and 1994 to study the dispersal of Trissolcus basalis (Wollaston), an egg parasitoid of the southern green stink bug, Nezara viridula (L.). Dispersal was determined by placing stink bug egg masses in tomato fields, releasing T. basalis at the center of each field, collecting the egg masses, and holding them to determine parasitism. Trissolcus basalis located egg masses within each field with no preference for direction or distance from the release point. Release of about 2,000 T. basalis adults in a 50 x 50 m field resulted in 90% parasitism of egg masses with 52.8 to 97.0% average parasitism of eggs in all directions. About 50% of the egg masses were parasitized when 369 T. basalis were released in a 50 x 50 m field and when 480 parasitoids were released in a 50 x 100 m field.