Field effectiveness of Acerophagus papayae, Anagyrus loecki, and Pseudleptomastix mexicana, three introduced parasitoids of Paracoccus marginatus, was investigated in 2005 and 2006 in three locations in Homestead, Florida on Hibiscus rosa-sinensis L. plants. Mealybug populations were initially established on three branches of each hibiscus plant inside closed-sleeve cages. The treatments, closed-sleeve cage, open-sleeve cage, and no-cage were applied to the three established mealybug populations in each plant. Number of Cryptolaemus montrouzieri larvae and adults, ants, and spiders were monitored in the treatments at 24, 48, and 72-hour intervals. After 72 h, the number of P. marginatus in the open-sleeve cage was higher than in the no-cage treatment but both were lower than the number in the closed-sleeve cage. Cryptolaemus montrouzieri larvae and adults, ants, and spiders were higher in the no-cage treatment than in the open-sleeve cage with no activity in the closed-sleeve cage. Acerophagus papayae had a higher percent parasitism than A. loecki in both the open-sleeve and the no-cage treatments. Between open-sleeve and no-cage treatments, Acerophagus papayae had a higher parasitism in the open-sleeve cage treatment. There was no P. mexicana activity in either of the treatments. Crypolaemus montrouzieri, ants, and spiders may have contributed to the overall low parasitism. The low parasitism by A. loecki may be due to its multiple host preference. Out of the three parasitoid species, parasitism by A. papayae caused the most mortality of P. marginatus. Supplemental data from laboratory studies were provided to explain the results.