Biocontrol introduction
Target pest: Epiphyas postvittana (Lepidoptera: Tortricidae), light brown apple moth
Agent introduced: Goniozus jacintae (Hymenoptera: Bethylidae)
Imported:
1922(?), 1969
Import source: Australia
Import notes:
Cameron et al. (1989) - in 1922 several pupal cocoons identified as Goniozus sp. ?anitpodum [but likely to have been G. jacintae - see Berry (1998) below] were sent from Australia to Nelson. In 1969 parasitised E. postvittana larvae were collected in eastern Australia and Tasmania and imported into quarantine at Nelson. One hundred and fifteen Goniozus sp. [but see Berry (1998) below for identification of voucher specimens] emerged, of which 100 were directly released.
Berry (1998) - the species imported in 1922 is likely to have been Goniozus jacintae, given the subsequent collection of G. jacintae in New Zealand in 1962, but it is also possible that it was self-introduced, either by wind or along with its host Epiphyas postvittana. There are no voucher specimens from the 1922 introduction, so the identity of the species (singular or plural) involved cannot be checked. The specimens imported 1969 were recorded as Goniozus sp. However, examination of voucher specimens has shown that the importation comprised a mixture of Eupsenella sp. 1, Goniozus jacintae and Sierola sp. 1.
Released:
1922(?), 1969
Release details:
Cameron et al. (1989) - attempts were made to mass-rear the species, imported in 1922, identified as Goniozus sp. ?antipodum [but likely to have been G. jacintae, see 'Import notes'], but the adult parasitoids escaped from rearing facility at Nelson, constituting a release. In 1969, 100 adults from the 1969 importation, were released into field cages at Appleby, near Nelson, and Nelson.
Berry (1998) - the 100 adults released in 1969 were considered to be Goniozus sp. However, examination of voucher specimens has shown that the importation comprised a mixture of Eupsenella sp. 1, Goniozus jacintae and Sierola sp. 1.
Establishment:
Berry (1998) - G. jacintae has been collected fairly widely in New Zealand (the Auckland, Bay of Plenty, Gisborne, Hawkes Bay, Wanganui and Nelson districts), including a collection in 1962, prior to the the probable 1969 release.
Impacts on target:
Charles et al. (1996) - three species of leafroller were recovered from berryfruit orchards in Hawkes Bay: the introduced Epiphyas postvittana and the endemic Planotortrix octo (greenheaded leafroller) and Ctenopseustis obliquana (brownheaded leafroller). More than 90% of parasitoids reared from these were D. tasmanica, the remainder either Glyptapanteles demeter or Goniozus sp., the latter found only in March and April. Parasitised larvae were not identified to species; it is assumed that all three leafroller species were attacked equally.
Lo et al. (2018) - a study to measure changes in the abundance and pest status of three leafroller species, the introduced Epiphyas postvittana and the endemic Planotortrix octo (greenheaded leafroller) and Ctenopseustis obliquana (brownheaded leafroller), in fruit growing areas of Hawke's Bay between 1976 and 2016, showed populations of all three species decreased substantially; however, P. octo and C. obliquana declined to a much greater extent than E. postvittana. Leafrollers damaged over 20% of apples receiving no insecticides during the 1980s but, subsequent to 2000, damage has been below 2%. Between 1994-1999 and 2008-2011, the numbers of immature leafrollers in searches on fruit crop and non-crop hosts decreased by 55% and the mean percentage of leafrollers parasitised per sample increased from 51% to 70%. The reduction in leafroller populations can be attributed to two key factors: increased biological control and the replacement of broad-spectrum insecticides with selective insecticides. In 1974-75, parasitism of leafroller larvae on fruit crops was 13%; in the 2000s, 69%. The decline in importance of leafrollers as pests has occurred on managed and unmanaged orchards, vineyards, and on non-crop shelter plants. In the 1970s and 1980s, leafrollers and their associated damage were highly visible on Hawke's Bay orchards, whereas, currently, they are difficult to find, even on unsprayed trees. From the 1994-1999 and 2008-2011 leafroller larvae collections, 8% of parasitoids reared from three fruit crops (apple, grape, boysenberry), and 5% from oak trees in shelter belts, were Goniozus spp.
Impacts on non-targets:
Charles et al. (1996) - Goniozus sp. reared from the New Zealand endemic leafrollers Planotortrix octo (greenheaded leafroller) and Ctenopseustis obliquana (brownheaded leafroller) in berryfruit orchards in Hawkes Bay [see 'Impacts on target' section, and Cameron et al. (1993) entry in 'General comments' section].
Berry (1998) - G. jacintae has been reared from two native endemic tortricids Ctenopseustis obliquana and Planotortrix notophaea (both pests of cultivated plants).
Lo et al. (2018) - the New Zealand endemic leafrollers Planotortrix octo (greenheaded leafroller) and Ctenopseustis obliquana (brownheaded leafroller) have declined in orchards vineyards and shelterbelts (where they are pests) in Hawkes Bay, at least partly as a result of parasitism by Goniozus spp. and other introduced biological control agents. These two species were the dominant leafrollers in the 1970s, whereas they are now rarely found on fruit crops.
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, J.A. (1998). The bethyline species (Hymenoptera: Bethylidae: Bethylinae) imported into New Zealand for biological control of pest leafrollers. New Zealand Journal of Zoology. Vol. 25: 329-333
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.
Charles JG, Walker JTS, White V. (1996). Leafroller phenology and parasitism in Hawkes Bay, New Zealand, canefruit gardens. New Zealand Journal of Crop and Horticultural Science 24 (2): 123-131 https://www.tandfonline.com/doi/pdf/10.1080/01140671.1996.9513944
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
