Biocontrol introduction
Target pest: Phthorimaea operculella (Lepidoptera: Gelechiidae), potato tuber moth
Agent introduced: Apanteles subandinus (Hymenoptera: Braconidae)
Imported:
1966, 1966-67, 1969-70
Import source:
Northern Argentina and southern Brazil via Australia (1966) and India (1966-67, 1969-70)
Import notes:
Cameron et al. (1989) - in 1966 there were two shipments, one in January and one in February, each of approximately 1,000 individuals, of A. subandinus from Australia to Nelson, New Zealand. All of the first shipment were dead on arrival; 12 adults emerged from the second shipment and were released. Between November 1966 and March 1967 there were 14 shipments of A. subandinus from the Commonwealth Institute of Biological Control station in India to Nelson, with all individuals being directly released. Between November 1969 and April 1970 there were a further seven shipments of A. subandinus from India; most were directly released although a small number were retained at Nelson for laboratory culture. A limited number were bred and a few released there before the laboratory host population became infected with a granulosis virus and the rearing programme was terminated. The Apanteles subandinus material had been originally sourced from northern Argentina and southern Brazil in 1963-64 and cultured at the Californian Station of CIBC; when this station closed, the colony was transferred to the Indian Station of CIBC, from where the 1966-67 and 1969-70 shipments were made to New Zealand. [Presumably the material imported from Australia in 1966 also originated from northern Argentina and southern Brazil, as the CIBC stations in California and India exported P. operculella biocontrol agents to all participant Commonwealth countries.]
Released:
1966
Release details:
Cameron et al. (1989) - twelve adults imported in February 1969 were released at Nelson, South Island. Approximate numbers released from the 1966-67 importations were 2,685 at Lincoln, Canterbury and Oamaru, North Otago, South Island (specific numbers at each site was not clear in the records), 1,175 at Nelson and 350 at Palmerston North, North Island. Approximate numbers released from the 1969-70 importations were 445 at Lincoln/Oamaru and 915 at Nelson. In late-March 1971, 800 adult A. subandinus were collected in the field from Nelson and sent to Lincoln for release; only a small proportion were females.
Establishment:
Cameron et al. (1989) - surveys for parasitised P. operculella were carried out at Lincoln, Canterbury and Oamaru, North Otago in the South Island from mid-1967 until late-1973. The first recovery of A. subandinus was at Oamaru in June 1967; it appears to have established there as it was recovered each year until sampling was ceased. Although these surveys did not detect A. subandinus at Lincoln, subsequent observations suggest it has established there. In the Nelson area of the South Island, from the last releases (1969-70), A. subandinus was known to have bred in the field for at least one generation; a subsequent sweep-net survey showed it was established there on P. operculella. No surveys were carried out in the North lsland, but A. subandinus was reared from potatoes from Pukekohe, Auckland in 1970; since it was not released there, it is assumed to have been transported there in potatoes from Palmerton North or the South Island.
Impacts on target:
Cameron et al. (1989) - surveys for the establishment of A. subandinus did not permit assessment of levels of parasitism or impacts on host populations except in Auckland. There, it was concluded that the parasitoid, which was active in winter, probably delayed P. operculella reaching high densities by three to fours weeks, i.e. one generation in early-summer. This effected some control, but overall gave little economic control of this pest. This finding confirmed other reports that this insect, by itself, fails to significantly reduce tuber damage. In winter, however, A. subandinus-induced mortality of 45% suggested a role in reduction of the overwintering P. operculella population. Nevertheless, sufficient hosts survived to cause a serious problem the following summer when parasitism by A. subandinus was about 10-15% in the tuber population.
Cameron et al. (1993) - Apanteles subandinus is categorised as exerting “partial” control (defined as “additional control remains commonly necessary but…pest outbreaks occur less frequently”) over Phthorimaea operculella.
Impacts on non-targets:
Gerard et al. (2011) - Apanteles subandinus has been recorded parasitising the leafrollers (family Tortricidae) Epiphyas postvittana [light brown apple moth], Ctenopseutis obliquana [brownheaded leafroller], Planotortrix octo [greenheaded leafroller] and Cnephasia jactatana [black-lyre leafroller]. All these species are orchard pests [although only E. postvittana is not native to New Zealand].
General comments:
Taxonomic note (27 Nov 22) - Fernandez-Triana et al. (2020) note that under the name Apanteles subandinus there is likely a complex of species, some of them not even related. They report two different species under this name in the Canadian National Collection of Insects, both reared from P. operculella: one from California, USA that clearly belongs to Apanteles, and perhaps represents the true A. subandinus, the other from Venezuela that clearly belongs to the genus Dolichogenidea. Furthermore, they point out that in the Barcode of Life Data System (BOLD) there are two Barcode Index Numbers (BINs) with the same name Apanteles subandinus but which are far apart from each other: one BIN (that is close to Dolichogenidea and not Apanteles) contains the Venezuelan specimens (and others from Chile), the other BIN (close to Apanteles and not Dolichogenidea) with specimens from Colombia and New Zealand. Rousse & Gupta (2013) considered the species as belonging to the genus Glyptapanteles and thus transferred it to that genus; however, Fernandez-Triana et al. (2020) state that from the figures in the Rousse & Gupta (2013) paper it is evident that the single female specimen they saw is not Glyptapanteles and transferred the species back to Apanteles, concluding that without further work this is the best placement that it can be currently assigned to.
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
Fernandez-Triana J, Shaw MR, Boudreault C, Beaudin M, Broad GR (2020). Annotated and illustrated world checklist of Microgastrinae parasitoid wasps (Hymenoptera, Braconidae). ZooKeys 920: 1-1089 https://doi.org/10.3897/zookeys.920.39128
Gerard PJ, Kean JM, Phillips CB, Fowler SV, Withers TM, Walker GP, Charles JG (2011). Possible impacts of climate change on biocontrol systems in New Zealand. Ministry of Agriculture and Forestry Technical Paper No: 2011/21 https://www.mpi.govt.nz/dmsdocument/6235-Possible-impacts-of-climate-change-on-biocontrol-systems-in-New-Zealand
Rousse P, Gupta A (2013). Microgastrinae (Hymenoptera: Braconidae) of Reunion Island: a catalogue of the local species, including 18 new taxa and a key to species. Zootaxa 3616(6): 501-547 http://dx.doi.org/10.11646/zootaxa.3616.6.1
