Survey of the natural enemies of Dysmicoccus mealybugs on pineapple in Hawaii

Surveys for mealybugs, associated natural enemies and ants were conducted i n abandoned pineapple fields on the Hawaiian islands of Oahu and Maui from July 1992 to November 1993. Whole plant samples were taken, and mealybugs a nd ants found were identified. Mealybug-infested plant parts were isolated and held until natural enemies emerged from parasitized host material. At s ample sites where only Dysmicoccus brevipes was present, its densities rang ed from a mean of 23 to 157 mealybugs per plant, while in areas with mixed populations of this mealybug and Dysmicoccus neobrevipes Beardsley, densiti es ranged from a mean of 23 to 118 mealybugs per plant. Ants were present a t all sample sites and on all dates. Pheidole megacephala (F.) was the most common ant species found. Anagyrus ananatis Gahan was the most common para sitoid reared. However, it attacked only D. brevipes, the dominant mealybug in the pineapple fields surveyed. Percent parasitization of D. brevipes by A. ananatis in the presence of ants ranged from 0.3 to 9.9%. Percent paras itization of D. brevipes and D. neobrevipes per plant by Euryrhopalus propi nquus Kerrich ranged from 0.05 to 2.2%. Mean densities of the predators Lob odiplosis pseudococci (Felt), Nephus bilucernarius Mulsant and Sticholotis ruficeps Weise ranged from 0.05 to 5.75, 0.1 to 1.8, and 0.05 to 0.2 indivi duals per plant, respectively.