Biocontrol introduction
Target pest: Epiphyas postvittana (Lepidoptera: Tortricidae), light brown apple moth
Agent introduced: Xanthopimpla rhopaloceros (Hymenoptera: Ichneumonidae)
Imported:
1967, 1969
Import source:
Australia
Import notes:
Cameron et al. (1989) - parasitised E. postvittana pupae were collected in eastern Australia and Tasmania in 1967 and 1969 and imported into quarantine at Nelson. Four X. rhopaloceros emerged in 1967; 31 emerged in 1969, of which 12 were directly released.
Munro (1998b) - most of the X. rhopaloceros imported to New Zealand came from the Mornington Peninsula, an apple-growing area in Victoria. They were also collected from research orchards in the Huon Valley, Tasmania, and from Gininderra, near Canberra, in the Australian Capital Territory.
Released:
1967
Release details:
Cameron et al. (1989) - in 1969, 12 adults were released into field cages at Nelson. Between 1967 and 1973 releases were made at Kerikeri, Hamilton, Kaingaroa Forest, Rotorua, Nelson and near Christchurch. Further releases were made in Christchurch during 1972, 1978-80 and 1984-87 from field collections.
Munro (1998a) - approximately 200 X. rhopaloceros individuals per site were initially released from 1967-73. Subsequent supplementary redistributions were made in both the North and South Islands until 1987, including approximately 200 redistributed from Nelson in the South Island to Havelock North in the North Island in 1980.
Establishment:
Cameron et al. (1989) - initially established from small releases made in Nelson but later disappeared. Confirmed established at Paihia in 1973 and during the next few years became very numerous and spread throughout the North Island. It was common in Wellington in 1985 and in 1986 was confirmed to be established in Nelson [although Munro (1998a) (see entry in 'Release details' section) reports X. rhopaloceros was redistributed from Nelson to Havelock North in 1980]. The attempts to establish it in Christchurch (1972, 1978-80, 1984-87) have not been successful.
Munro (1998a) - Xanthopimpla rhopaloceros established at a Nelson, South Island release site in 1969; however, no further records occurred in the Nelson/Marlborough regions until 1992 [although Munro (1998a) also states that X. rhopaloceros was redistributed from Nelson to Havelock North in 1980]. The first North Island records of X. rhopaloceros came from Kerikeri and Hamilton in 1973. It now occurs from the northern extreme of the North Island to as far south as Murchison, Nelson and Blenheim in the South Island. It has been collected on the Aldermen Islands, 20 km from the Coromandel Peninsula.
Munro (1998b) - establishment of X. rhopaloceros was less successful in the South Island than the North Island, which was completely colonised in 14 years, dispersing at an average rate of 19.2 km/year. It established at Nelson in the South Island for a short period during the late-1960s after its release and then disappeared. It was not seen in the Nelson area for another 20 years, when it was detected in 1989 at Nelson and Blenheim, suggesting re-establishment of a South Island population by natural dispersal from the North Island rather than from a remnant Nelson population. Comparisons of distribution in New Zealand with that in its native Australia indicates that climatic conditions may have played a major role in the areas of establishment in New Zealand. The mean winter temperature may be a limiting factor in the dispersal in New Zealand. With the wide distribution in New Zealand of host Tortricidae and tortricid host plant groups that also occur in Australia it is perhaps not surprising that X. rhopaloceros has invaded some native habitats in New Zealand.
Impacts on target:
Cameron et al. (1989) - a PhD study by C.J.Green in 1984 showed little interaction of the introduced parasitoids Trigonospila brevifacies, X. rhopaloceros and Glabridorsum stokesii with hosts on apple trees in Auckland. The study failed to show any regulatory role of these parasitoids, except perhaps for parasitism of Cydia molesta (oriental fruit moth) by G. stokesii. The circumstantial evidence of reduction in archipine tortricid populations in orchards has not been quantified.
Munro (1998b) - Xanthoplimpla rhopaloceros has established in all North Island commercial fruit-growing regions and is commonly found where insecticide use is limited. Its potential in integrated pest management systems for tortricid pests in fruit crops is being investigated.
Lo et al. (2018) - the establishment and subsequent spread of the parasitoids X. rhopaloceros, Trigonospila brevifacies and Glabridorsum stokesii added to overall leafroller parasitism by increasing parasitism of late larval and pupal stages [see Cameron et al. (1993) entry in 'General comments' section]. However, from 1994-1999 and 2008-2011 leafroller larvae collections in Hawke's Bay, X. rhopaloceros was not reported as a component of the parasitoid guild reared from three fruit crops (apple, grape, boysenberry), or as a component of the parasitoids reared from oak trees in shelter belts.
Impacts on non-targets:
Cameron et al. (1989) - X. rhopaloceros also parasitises a range of smaller tortricids in New Zealand, in addition to its normal archipine tortricid hosts.
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.
Munro (1998b) - there is some concern that X. rhopaloceros attacks native lepidopteran species within the native habitats which it has invaded.
Munro & Henderson (2002) - Xanthopimpla rhopaloceros has been recorded parasitising native tortricid moth pupae on a few occasions in native forests.
General comments:
Cameron et al. (1993) - native tortricid pest species were included as targets in the 1967-69 programme against E. postvittana. By 1984, changing attitudes to conflicts between conservation and biological control were recognized and more specific consideration was given to the preservation of non-target native species.
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 https://doi.org/10.1080/09583159309355294
Lo PL, Walker JTS, Hedderley DI, Cole LM. (2018). Reduction in leafroller (Lepidoptera: Tortricidae) abundance in orchards and vineyards 1976-2016, in Hawke's Bay, New Zealand. Agricultural and Forest Entomology 20 (4): 505-513
Munro VMW (1998a). 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 VMW and Henderson IM (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
Munro WMW (1998b). A retrospective analysis of the establishment and dispersal of the introduced Australian parasitoids Xanthopimpla rhopaloceros (Krieger) (Hymenoptera: Ichneumonidae) and Trigonospila brevifacies (Hardy) (Diptera: Tachinidae) within New Zealand. Biocontrol Science and Technology 8(4): 559-571 https://doi.org/10.1080/09583159830072
