Biocontrol introduction
Target pest: Cydia molesta (Lepidoptera: Tortricidae) = Grapholita molesta, oriental fruit moth
Agent introduced: Trigonospila brevifacies (Diptera: Tachinidae)
Imported:
1967, 1969
Import source:
Australia (eastern Australia and Tasmania)
Import notes:
Cameron et al. (1989) - imported T. brevifacies were released directly from quarantine into the field in 1967. It was also cultured in part and releases of cultured individuals were made 1967-1972.
Released:
1967
Release details:
Cameron et al. (1989) - 39 (1967) and 20 (1969) adults were released into tree cages enclosing E. postvittana infestations at Appleby, Nelson. Subsequent releases were made until 1972 at Kerikeri, Hamilton, Tauranga, Nelson and Christchurch. It was redistributed to Havelock North, Christchurch and Nelson in 1981-82 and Christchurch in 1987.
Establishment:
Cameron et al. (1989) - adults of a new generation were observed in September 1967 at Appleby, but the parasitoid failed to become established at this locality. First reported established in Kerikeri in 1972. Since then it has spread to many regions in the North Island and is found as far south as Levin.
Munro (1998) - Trigonospila brevifacies has established throughout the North Island. There were no records of it having established at South Island sites by 1997. However, in the summer of 1997/98 several were collected at Nelson. Because there were no post-release records of T. brevifacies in the South Island it is assumed that it has recently colonised the South Island from the North Island. Trigonospila brevifacies is also present on the Alderman Islands, Three Kings Island, Poor Knights Island, the Mercury Islands and Kapiti Island.
Impacts on target:
Cameron et al. (1989) - although widespread and numerous on other hosts in the Auckland area, only two records exist for C. molesta, both at Kumeu Research Orchard, Auckland; in 1982 and 1984. This, plus a lack of records of T. brevifacies from C. molesta in Australia, probably indicates that C. molesta is not an ideal host, perhaps because its larvae are only available for oviposition by T. brevifacies for short periods while changing feeding sites or seeking suitable pupation sites.
Impacts on non-targets:
Green (1984) - Trigonospila brevifacies is recorded from the endemic tortricids Ctenopseustis obliquana (Walker), "Cnephasia" jactatana (Walker) and Epalxiphora axenana Meyrick, as well as the natives Platyptilia falcatalis Walker [syn. Amblyptilia falcatalis] (Lepidoptera: Pterophoridae), Hierodoris atychioides (Butler) (Lepidoptera: Oecophoridae), Staphmopoda "skelloni" (Butler) (Lepidoptera: Staphmopodidae) and an identified species of Lepidoptera: Psychidae. It has also been reared from a mixed collection of larvae including the natives Pasiphila lunata (Philpott) (Lepidoptera: Geometridae) and the pterophorid Aciptilia monospilalis Walker [syn. Pterophorus monospilalis]. These records show that T. brevifacies is by no means restricted to tortricid hosts from orchard habitats in New Zealand. Adult T. brevifacies have been found in native forest in Northland and Auckland.
Roberts (1986) - hard data are lacking, but the spread of T. brevifacies seems to be associated with a decline in abundance of some native leafrollers. For example, the leafroller species which was previously common on mangroves is now very hard to find, and of those which are found, a very high percentage are parasitised by T. brevifacies. In addition, the increase in T. brevifacies seems to have been associated with a decline in abundance of the parasitoid Xanthopimpla rhopalocerus [introduced as a biocontrol agent for the tortricid Epiphyas postvittana (light brown apple moth)] in Auckland gardens, though there is no reason to believe it has been completely replaced.
Cameron et al. (1989) - the native oecophorid Stathmopoda horticola is also reported as a host of T. brevifacies. It was known from the outset that this parasitoid accepted a range of archipine tortricids as hosts but it has adapted to an additional range of hosts in other lepidopteran families. Concern has been expressed at the broad host range of introduced Australian parasitoids like T. brevifacies. It is very unlikely that any host species will become extinct as a result of their activities, but some species in some habitats have probably been reduced in abundance during the early "explosive" phase of parasitoid establishment. Native hosts affected in this way will probably increase in numbers again as parasitoid numbers decline. There is no evidence that native host population dynamics have been affected, though no detailed studies have been undertaken.
Berry (1990) - the parasitoid complex reared from field-collected specimens of the native oecophorid moth Hierodoris atychioides was dominated by the introduced parasitoids Trigonospila brevifacies and Xanthopimpla rhopaloceros.
Cameron et al. (1993) - in New Zealand, T. brevifacies is the only parasitoid introduced for biocontrol recorded attacking non-pest native species in an unpredicted manner and the only introduced biocontrol agent that is thought to have negative effects on non-target non-pest species. It has been reared from six lepidopteran families [see the Green (1984) entry above in this section] in a wide range of arboreal habitats. Its impact has not been assessed but suggestions that it affects populations of a mangrove tortricid Planotortrix avicenniae [see the Roberts (1986) entry above in this section] support the need for an evaluation. Although it is commonly reared from alternative native hosts, it is unknown whether this parasitism has any effect on their abundance.
Munro (1997) - Eutorna phaulocosma Meyrick (Lepidoptera: Oecophoridae) (an accidentally introduced Australian moth and a minor pest of cane fruit crops) is identified as a new host of T. brevifacies. This parasitoid is found throughout the North Island in a range of habitats including orchards, urban gardens, exotic forest, farmland and native forest, where it has acquired a wide host range. Records to March 1996 indicate that it parasitises 14 species (10 of which are pests) from five families (Oecophoridae, Tortricidae, Pterophoridae, Geometridae and Stathmopodidae). In Australia five species from three families (Tortricidae, Pyralidae and Gelechiidae) are parasitised.
Munro (1998) - since many offshore islands in New Zealand function as conservation areas for native plants and animals, it is of concern that T. brevifacies has established on some of these islands.
Mauchline & Withers (2000), Withers (2001) - Trigonospila brevifacies heavily parasitises Strepsicrates macropetana (Eucalyptus leafroller) in New Zealand; parasitism of leafroller pupae can be as high as 45%. Strepsicrates macropetana is a pest in New Zealand; T. brevifacies and other natural enemies moderate its populations and reduce its pest status.
Munro & Henderson (2002) - the parasitoid guild attacking tortricids in native broadleaf/podocarp forests was studied in the central North Island. Trigonospila brevifacies shared its host range with 12 native and one introduced parasitoid species and all these parasitoid species were less abundant than T. brevifacies. Trigonospila brevifacies attacked the most species of host, was the dominant parasitoid species on all but two host species and had the highest level of parasitism across the host guild, constituting between 15.6 and 79.5% of parasitism occurring on hosts sampled. In forest habitats T. brevifacies may be having undesirable effects on native fauna by displacing native parasitoids through direct competition. Hosts species parasitised, in addition to those mentioned previously in this section, were Planotortrix octo, P. excessana, P. notophaea, Apoctena flavescens and Strepsicrates ejectana.
References
Berry JA (1990). Two parasitoid complexes: Hierodoris atychioides (Butler) (Lepidoptera: Oecophoridae) and Iceya purchasi Maskell (Homoptera: Margarodidae). New Zealand Entomologist 13: 60-62
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
Green, O.R. (1984). New zealand host and locality records for an introduced tortricid parasite, Trigonospila brevifacies (Diptera: Tachinidae). New Zealand Entomologist 8. 69-71
Mauchline N, Withers TW (2000). Strepsicrates macropetana, Eucalyptus leafroller. Pests and diseases of forestry in New Zealand. New Zealand Farm Forestry Association. https://www.nzffa.org.nz/farm-forestry-model/the-essentials/forest-health-pests-and-diseases/Pests/Strepsicrates-macropetana
Munro, V.M.W. (1997). Eutorna phaulocosma Meyrick (Lepidoptera: Oecophoridae), a new host for the introduced Australian parasitoid Trigonospila brevifacies Hardy (Diptera: Tachinidae). New Zealand Entomologist 20. 71-72
Munro, V.M.W. (1998). A record of the releases and recoveries of the Australian parasitoids Xanthopimpla rhopaloceros Krieger (Hymenoptera: Ichneumonidae) and Trigonospila brevifacies Hardy (Diptera: Tachinidae) introduced into New Zealand for leafroller control. New Zealand Entomologist 21: 81-91
Munro, V.M.W. and Henderson, I.M. (2002). Nontarget effect of entomophagous biocontrol: Shared parasitism between native lepidopteran parasitoids and the biocontrol agent Trigonospila brevifacies (Diptera: Tachinidae) in forest habitats. Environmental Entomology 31 (2). 388-396
Roberts LIN (1986). The practice of biological control - implications for conservation, science and the community. The Weta 9(2): 76-84
Withers TM (2001). Colonization of eucalypts in New Zealand by Australian insects. Austral Ecology 26: 467-476 https://doi.org/10.1046/j.1442-9993.2001.01140.x
