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Biocontrol introduction

Target pest: Epiphyas postvittana (Lepidoptera: Tortricidae), light brown apple moth

Agent introduced: Goniozus ?antipodum (Hymenoptera: Bethylidae)

Imported:

1922

Import source:

Australia

Import notes:

Cameron et al. (1989) - in 1922 several pupal cocoons identified as Goniozus sp. ?anitpodum were sent from Australia to Nelson.

Berry (1998) - the imported species is likely to have been Goniozus jacintae, given the subsequent collection of G. jacintae in New Zealand in 1962. There are no voucher specimens from the 1922 introduction, so the identity of the species (singular or plural) involved cannot be checked.

Released:

1922

Release details:

Cameron et al. (1989) - attempts were made to mass-rear the species imported in 1922, but the adult parasitoids escaped from rearing facility at Nelson, constituting a release.

Establishment:

Cameron et al. (1989) - subsequent to the "release" in 1922, G. antipodum was found to be common in other districts and assumed to be present in New Zealand before importation [which is likely to have been G. jacintae anyway - see 'Import notes' section].

Impacts on target:

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:

Berry (1998) - the species introduced in 1922 is likely to have been G. jacintae; this speices has been recorded from two 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.

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.

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