Mass Rearing Biology of Larval Parasitoids (Hymenoptera: Braconidae: Opiinae) of Tephritid Flies (Diptera: Tephritidae) in Hawaii

Abstract

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), the melon fly, Dacus cucurbitae Coquillett, and the oriental fruit fly, Dacus dorsalis Hendel, are major pests of fruits and vegetables in Hawaii. D. cucurbitae was introduced into Hawaii from the Orient in 1895 (Back & Pemberton 1917); C. capitata from Australia about 1910 (Back & Pemberton 1918); and D. dorsalis from the Pacific Islands in 1945 (Van Zwaluwenburg 1947). Immediately after the establishment of these fruit flies, importation of exotic parasitoids into Hawaii from Africa, Asia, and Australia resulted in outstanding biological control (Back & Pemberton 1918, Willard 1920, Nishida 1955, Bess & Haramoto 1961, Clausen et al. 1965). Psyttalia fletcheri (Silvestri), a larval parasitoid of D. cucurbitae was introduced into Hawaii from India in 1916 and by 1918 parasitization of more than 80% was obtained for D. cucurbitae larvae collected from cultivated cucurbits (Willard 1920). However, in recent years, parasitization of this species was about 40% (Newell et al. 1952, Nishida 1955). Willard and Mason (1937) reported that biological control of C. capitata in Hawaii before entry of D. dorsalis centered on the larval parasitoids, Opius humilis Silvestri and Diachasmimorpha tryoni (Cameron) (=O. tryoni). O. humilis attained its maximum parasitization in 1915, and D. tryoni was the dominant species from 1917 to 1933 (Willard & Mason 1937). Between 1947 and 1952, many parasitoid species were brought into Hawaii to control D. dorsalis (Clausen et al. 1965). However, only three became widespread and 406abundant: Biosteres arisanus (Sonan) (= Opius oophilus Fullaway), Diachasmimorpha longicaudata (Ashmead) (= O. longicaudatus), and Biosteres vandenboschi (Fullaway) (= O. vandenboschi) (Van Den Bosch et al. 1951, Bess & Haramoto 1961, Clausen et al. 1965). These three braconid species were also effective in parasitizing C. capitata as there were no significant differences in parasitization in cases where the tephritids present were all D. dorsalis, all C. capitata, or a combination of the two (Bess & Haramoto 1961, Haramoto & Bess 1970). Parasitization averaged 60% or more of tephritids obtained from coffee and guava fruits on all of the Hawaiian islands since 1951 (Haramoto & Bess 1970). Moreover, Haramoto and Bess (1970) reported that since 1951, when B. arisanus became the dominant species, parasitization by D. longicaudata, D. tryoni,& B. vandenboschi has accounted for less than 4% of the total parasitization of the two tephritids on guava and coffee. However, in more recent studies in the Kula area of Maui, Hawaii, Wong et al. (1984) and Wong & Ramadan (1987) found that other opiine as well as B. arisanus are important in regulating tephritid populations. In Kula during a 5-year study, B. arisanus accounted for 74% of the total parasitization. However, D. longicaudata exceeded 30% of the total parasitization in 1979 from infested peaches and in 1985 from loquats; D. tryoni accounted for 33% in 1987 and 29% in 1985 from loquats (Wong & Ramadan 1987).