Studies on natural enemies of a mealybug, Phenacoccus Pergandei Cockerell. II

Phenacoccus pergandei has but one generation each year, overwintering in the mature nymphal stage, attaining the adult from April to May, ovipositing from the middle of April to the middle of June and beginning to hatch in the first decade of May in Fukuoka district. The first emergence of the parasites from overwintering nymphs of the mealybug occurs from the latter part of March to the last decade of April. Anagyrus schonherri and Aphycus albicornis oviposit on the adult female of the mealybug. From these hosts the second emergence of the parasites occurs from the first decade of May to the first decade of June. Among the members of mealybug parasites, Allotropa utilis has only one generation, emerging from the first decade of May to the middle of June. The adult parasites oviposit on the first instar nymphs of the mealybug. The adults of a predacious coccinellid, Scymnus phosphorus, emerge from the egg-masses of the mealybug from the latter part of May to the last decade of June (Fig. 1). The geographical distribution of these species is shown in Table 1. Biological notes were added on the primary parasites, Anagyrus schonherri and Aphycus albicornis, and on a hyperparasite, Cheiloneurus sp. ; i. e. descriptions of eggs (including the ovarian eggs), larvae and pupae, the habits of the adults, their longevities, sex ratio and the parthenogenesis. The egg of Anagyrus schonherri b elongs to the \u22 banded type \u22 and that of Aphycus albicornis and Cheiloneurus sp. belongs to the \u22 unbanded type.\u22 The younger stage larva of Anagyrus schonherri is an \u22 encyrtiform \u22, that of Aphycus albicornis is a \u22 spherical type \u22 and that of Cheiloneurus sp. is a \u22 caudate type.\u22 The female of overwintering generation of Aphycus albicornis oviposits on the adult female of host mealybug inserting her ovipositor vertically through the host integument to deposit eggs deeply in the host body, while Anagyrus schonherri inserts her ovipositor from the side of the host body and deposits her eggs under the host integument projecting stalks of eggs through the derm to exterior. The adult of Anagyrus schonherri (female, spring generation) lives for 143 days in maximum on honey in a glass tube in natural room condition. Aphycus albicornis lives for 116 days and Cheiloneurus sp. lives for about 70 days in maximum in the same condition as above. The sex ratio of these species is shown in Tables 3, 5 and 6. Anagyrus schonherri and Aphycus albicornis produce only male when the reproduction is parthenogenetic (arrhenotokous parthenogenesis).前報に引続いて,オオワタコナカイガラムシの天敵の出現時期,地理的分布および主な2種の寄生蜂 Anagyrus sehtinherri シェーンヘールトビコバチと Aphycus albieornis オオワタコナカイガラヤドリバチ並びに二次寄生蜂 Cheiloneurus sp.の生態について述べる