Diachasmimorpha kraussii (Fullaway, 1951)

Taxonomic History / Nomenclature
In publications prior to about 1988, the species of Diachasmimorpha were placed either in the genus Opius or in the genus Biosteres.
See comments under the Diachasmimorpha page, especially under the longicaudata species group.
Known from Australia where it is an endemic parasitoid of Bactrocera tryoni.

Released in Hawaii in the late 1940s/early 1950s during the Oriental fruit fly program (Clausen et al. 1965) and although recoveries were made initially (Bess et al. 1961), it apparently did not become established until re-introduced by Messing in the 1990s.

Biology / Hosts
Most commonly recorded from Bactrocera tryoni (Froggatt), but also reared from B. neohumeralis (Hardy), B. aquilonis (May), B. halfordiae (Tryon), B. melas (Perkins and May), B. visenda (Hardy), B. cacuminata (Hering), B. kraussi (Hardy), B. jarvisi (Tryon), and B. murrayi (Perkins) (see details of host records provided in Rungrojwanich and Walter (2000a), including corrections of some older records).

Established in Hawaii on B. latifrons.

Biology and Behavior
Detailed studies were published by Rungrojwanich and Walter (2000a and 2000b)
Biology - Host Range Testing
In host range testing, D. kraussii was found to reproduce successfully on Bactrocera latifrons and Ceratitis capitata, but failed on Bactrocera dorsalis and B. cucurbitae due to egg encapsulation (Messing and Ramadan 2000). This supports earlier experiments indicating that only a very small percentage of these parasitoids were able to successfully complete development on B. dorsalis (Clausen et al. 1965).

In laboratory tests to evaluate the response of D. krausii to 4 non-target tephritids in Hawaii, Duan and Messing (2000) report that from 3 of the hosts, Trupanea dubautiae (Bryan), Ensina sonchi (L.), and Procecidochares utilis (Stone), no parasitoids emerged but 2.3-5% of dead fly puparia or larvae contained dead D. krausii eggs and/or first instar larvae. From the fourth tephritid host, Eutreta xanthochaeta Aldrich, a mean of 1.8 and 0.8 adult parasitoids emerged per 10 exposed galls (infested with 10 fly larvae each), and 15-26% of dead fly puparia or larvae contained dead parasitoids. Three of the four tephritid hosts tested are considered beneficial for weed control in Hawaii (Eutreta xanthochaeta, Ensina sonchi, and Procecidochares utilis) and the fourth is an endemic flowerhead infesting tephritid (Trupanea dubautiae). Additional non-target work was conducted in California as part of an olive fly biological control program (Kuslitzky et al. 2011).

Biological Control
D. krausii has been re-introduced to Hawaii recently against Bactrocera latifrons and Ceratitis capitata (e. g. Messing and Ramadan 2000, Duan and Messing 2000). It was first introduced to Hawaii in 1949 against Bactrocera dorsalis but failed to become established (Clancy et al. 1952), perhaps due to a lack of suitable hosts at the release sites (Messing and Ramadan 2000).