Abstract:  We investigated the potential impact of three opiine tephritid fruit fly parasitoids: Fopius arisanus (Sonan), Fopius caudatus (Szépligeti) and Fopius ceratitivorus Wharton, on the non‐target native Hawaiian tephritid, Trupanea dubautiae (Bryan), infesting flowerheads of the endemic Asteraceae shrub Dubautia raillardioides Hillebrand. The three species are the only known opiine fruit fly parasitoids that attack host eggs (but occasionally attack first instars). F. arisanus, which originated in southeast Asia, is now widely established in Hawaii and elsewhere in the world, while the other two are African species currently in quarantine in Hawaii. In the laboratory, field‐collected flowerheads of D. raillardioides containing T. dubautiae eggs and first instar larvae were exposed to naïve female wasps of each of the three Fopius species in the absence (no‐choice test) or presence (choice test) of papaya fruit infested with eggs of the Mediterranean fruit fly Ceratitis capitata (Wiedemann), the parasitoids’ normal host. All three Fopius species visited the papaya fruit much more often than the flowerheads, and displayed normal ovipositional responses (probing and stinging) on the fruit in the choice test. None of the three parasitoid species showed ovipositional responses to flowerheads in either choice or no‐choice tests. As a result, not a single T. dubautiae egg or larva was attacked by any of the three parasitoids, indicating that these parasitoids of pest tephritids are unable to recognize the microhabitats of flowerhead‐feeding tephritids. The results suggest minimal risk of non‐target impact in these biological control agents.

Aprostocetus exertus La Salle (Hymenoptera: Eulophidae: Tetrastichinae) is described as a parasitoid of the invasive Erythrina Gall Wasp, Quadrastichus erythrinae Kim (Hymenoptera: Eulophidae: Tetrastichinae). The description is based on material originally collected in Tanzania and South Africa. This species is described because of its potential as a biological control agent against the Erythrina Gall Wasp.

Diachasmimorpha tryoni (Cameron) (Hymenoptera: Braconidae) is a larval parasitoid that has been mass-reared for augmentative biological control against the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in Hawaii and other regions. To improve performance of female wasps in biological control programs, we conducted a series of experiments to investigate male wasp reproductive performance and its role in female reproductive success. The results showed that D. tryoni males remained close to the emergence (release) site following release. Males emerged earlier than females and male’s capacity to inseminate females reached the highest level (inseminated 9.2 ± 0.4 females/day) on the second day after eclosion in synchronization with female emergence peak; allowing males encountering most receptive females to enhance their mating success. Mating rates under normal rearing conditions (200 pairs per cage) reached optimum 100% insemination after 5 d. However, oviposition experience prior to mating impaired female’s receptivity as a percentage of inseminated females reduced to 17.5 ± 4.8%, while 70.0 ± 4.1% females without prior oviposition experience accepted mating. Mating reduced male’s survivorship and the potential lifetime fecundity of females, although multiple mating increased percentage of female offspring. Overall, influence of male density on the female oviposition rate and offspring sex ratio was not detected under captive rearing conditions. These results suggest that local and early mating is important for male’s reproductive success and females must be allowed to mate before they are exposed to hosts or released in the field to achieve their full reproductive potential.

Whitefly species of Aleurocanthus spiniferus (Quaintance) and A. woglumi Ashby (Hemiptera: Aleyrodidae) are serious pests of citrus and other important fruit crops. The problem of citrus has initiated the successful introduction of several natural enemies for biocontrol programs in Hawaii and many other countries. Here, we summarized the history of infestation and biocontrol efforts of the two whiteflies in Hawaii for possible parasitoid importation into Greece. Two Platygasteridae (Amitus hesperidum Silvestri, A. spiniferus (Brethes), and three Aphelinidae (Encarsia clypealis (Silvestri), E. smithi (Silvestri), E. perplexa Huang, and Polaszek) were released in Hawaii for biocontrol of the citrus whiteflies during the period 1974–1999. The aphelinid Cales noacki Howard, purposely released for Aleurothrixus flococcus (Maskell) in 1982, was also reported to attack other whiteflies, including Aleurocanthus species, on citrus. An additional aphelinid parasitoid, Encarsia nipponica Silvestri, native to Japan and China, was accidentally introduced and found to attack both citrus whiteflies on the islands. Since the colonization of introduced parasitoids in infested fields on four Hawaiian Islands, no survey has been conducted to evaluate their potential impact. We conducted two short surveys during September–November 2022 on the islands of Kauai, Hawaii, and Oahu to introduce the dominant parasitoids to Greece for the biocontrol of A. spiniferus. Results showed that the infestation level was very low on Kauai, Hawaii, and Oahu Islands, with a mean infestation level range of 1.4–3.1 on Hawaii and Oahu Islands, mostly on pummelo and sweet orange, with no detection on the island of Kauai. The dominant parasitoid was characterized as Encarsia perplexa, using molecular analysis. Its parasitism rates ranged from 0 to 28% on the island of Hawaii and 11 to 65% on the island of Oahu. Emerged parasitoids have been reared in Greece for evaluation. This was the first field survey of Hawaii since the introduction and release of citrus whitefly natural enemies.