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Biocontrol introduction

Target pest: Icerya purchasi (Hemiptera: Monophlebidae), cottony cushion scale

Agent introduced: Cryptochetum iceryae (Diptera: Cryptochetidae)


1888, 1889 1922, 1925

Import source:


Import notes:

Cameron et al. (1989) - there were two importations of C. iceryae in 1888 from South Australia (one to Nelson in the South Island, the destination of the other not specified) and one importation in 1889 [presumably also from South Australia] to Napier, Hawke’s Bay in the North Island. A consignment of I. purchasi parasitised by C. iceryae was sent from New South Wales, Australia to Nelson in 1922. Along with C. iceryae, chalcidoid wasps, suspected to be hyperparasitoids of C. iceryae, emerged from this consignment. Precautions were taken to prevent the establishment of these chalcidoids and there are no records of them being established in New Zealand. There was a further importation of C. iceryae from Australia in 1925 [the place of origin in Australia and destination in New Zealand not specified].



Release details:

Cameron et al. (1989) - there were [presumably, based on importation details - see ‘Import notes’ section] releases at least at Nelson, South Island in 1888 and 1922 and Napier, Hawke’s Bay, North Island in 1889. A 1936 publication reported that the introduction and establishment of C. iceryae was attempted in 1925, but without success [implying there were releases at this time, although no details are available].


Cameron et al. (1989) - in 1889 C. iceryae was reported as having an impact on I. purchasi populations in Nelson. Publications from 1940, 1950 and 1959 record the establishment of I. purchasi in New Zealand, with recoveries from Northland, Auckland, Taurangi and Whanganui in the North Island and Nelson and Canterbury in the South Island.

Impacts on target:

Cameron et al. (1989) - in 1889 I. purchasi was recorded as ‘giving much trouble’ at Nelson although it was noted it was kept somewhat in check by C. iceryae. There is no doubt that the introductions of C. iceryae and the coccinellid Novius cardinalis [see Novius cardinalis introduction record] have subsequently resulted in excellent control of I. purchasi in New Zealand. While no detailed evaluations have been carried out, it is generally understood that the coccinellid is the major controlling agent.

Cameron et al. (1993) - Cryptochetum iceryae is categorised as exerting “complete” control (defined as “control of the target over an extensive area so that pest outbreaks are rare or other control treatments are rarely necessary”) over I. purchasi.


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