RESPONSE BY ENCAPSULATION OF 4 MEALYBUG SPECIES (HOMOPTERA, PSEUDOCOCCIDAE) TO PARASITIZATION BY ANAGYRUS-PSEUDOCOCCI

The frequency of encapsulatio of eggs of Anagyrus pseudococci (Girault) (Hymenoptera: Encyrtidae) by four mealybug species: Planococcus citri (Risso), Pl. vovae (Nasonov), Pl. ficus (Signoret) and Pseudococcus cryptus Hempel (=citriculus Green), was studied under controlled laboratory conditions. The aggregate percentage of encapsulated eggs (AE) and the percentage of efficient encapsulation (EE) (= percent parasitized mealybugs wherein encapsulation prevented the development of all parasitoid larvae) by Pl. citri and Pl. vovae did not differ significantly (39.0% vs 38.2% AE and 15.4% vs 17.6% EE, respectively), but was significantly higher than in Ps. cryptus (16.2% AE and 5.4% EE). Encapsulation by Pl. vovae was significantly higher than by Pl. ficus (38.2% vs 20.1% AE and 17.6% vs 7.7% EE, respectively). Neither the host plant nor the rearing temperature significantly affected the incidence of parasitoid encapsulation. It is suggested that A. pseudococci displays a relatively low physiological adaptation to Pl. citri; thus, in a citrus grove, for example, ca 40% of the parasitoid egges might be lost due to encapsulation. The question of a possible association between encapsulation and host-parasitoid relationships among the mealybugs studied and A. pseudococci, is discussed.