Biocontrol introduction
Target pest: Mythimna separata (Lepidoptera: Noctuidae), cosmopolitan armyworm
Agent introduced: Trichogramma chilonis (Hymenoptera: Trichogrammatidae)
Imported:
1974
Import source:
Taiwan via Bangalore, India
Import notes:
Cameron et al. (1989) - four species of Trichogramma, including a total of 20,000 Trichogramma chilonis (imported as T. australicum [see taxonomic note in the ‘General comments’ section]), were imported in six shipments in 1974 from cultures held at the Commonwealth Institute of Biological Control Indian Station in Bangalore, India. The T. chilonis culture had originated from Taiwan. It was reared at Bangalore on Corcyra cephalonica. In New Zealand, frozen eggs of all four main target pests (Agrotis ipsilon, Chrysodeixis eriosoma, Helicoverpa armigera, Mythimna separata) were used to mass rear T. chilonis for release. It was also shown to develop satisfactorily on Graphania mutans, Ctenoplusia albostriata and Galleria mellonella.
Released:
1974
Release details:
Cameron et al. (1989) - a total of 530,000 T. chilonis were released at approximately 12 locations between Waipu (north of Auckland) and Pukekohe (south of Auckland) in the North Island between February 1974 and May 1975.
Establishment:
Cameron et al. (1989) - there have been no recoveries of T. chilonis. Surveys carried out one month after releases ceased did not detect any parasitism by this parasitoid, and subsequent surveys (of H. armigera and Chrysodeixis eriosoma eggs over a wide area of Northland and Auckland in 1976 and intensive sampling of noctuid eggs in tomatoes in the Auckland area) have confirmed the failure to establish of T. chilonis.
Impacts on non-targets:
Cameron et al. (1993) - Trichogramma chilonis was released after being reared on a range of native and introduced noctuids considered as potential alternative hosts. This is an example of a biocontrol programme where acceptance of native species as hosts was considered to be advantageous to the potential establishment and success of the agent.
General comments:
Taxonomic note (2 November 2022) - Trichogramma chilonis was imported as T. australicum. Cameron et al. (1989) state that the species imported as T. australicum is referred to in a 1982 publication by Pinto et al. as T. chilonis. While that publication does not seem to be readily available, in another paper Pinto et al. (1982) provide a redescription of T. australicum and note that “it now appears that most previous references to T. australicum are instead assignable to T. chilonis.”
References
Cameron PJ, Hill RL, Bain J, Thomas WP (1989). A Review of Biological Control of Invertebrate Pests and Weeds in New Zealand 1874-1987. Technical Communication No 10. CAB International Institute of Biological Control. DSIR Entomology Division. 424p.
Cameron PJ, Hill RL, Bain J, Thomas WP (1993). Analysis of importations for biological control of insect pests and weeds in New Zealand. Biocontrol Science and Technology 3(4): 387-404
Pinto JD, Oatman ER, Platner GR (1982). Trichogramma australicum Girault (Hymenoptera: Trichogrammatidae): redescription and lectotype designation. Pan-Pacific Entomologist 58(1): 48-52 https://www.biodiversitylibrary.org/part/270242
