Biocontrol introduction
Target pest: Pseudococcus viburni (Hemiptera: Pseudococcidae) = Pseudococcus affinis, Pseudococcus obscurus, obscure mealybug
Agent introduced: Coccophagus gurneyi (Hymenoptera: Aphelinidae)
Imported:
1928, 1933
Import source:
Australia via California, USA
Import notes:
Cameron et al. (1989) - in December 1928, a consignment of C. gurneyi was sent to the Cawthorn Institute in Nelson from California, USA, originating from material collected in Australia between August 1927 and February 1928. There were no releases from this consignment and by October 1929 all had died. In February 1933, a shipment of four female and one male C. gurneyi was sent from California to Nelson, from which a thriving colony was established for releases.
Released:
1934
Release details:
Cameron et al. (1989) - releases were made in different parts of New Zealand in the latter half of the 1933-34 season and the 1934-35 season. Approximately 27,000 individuals were released in the Nelson district of the South Island and in the North Island from Lower Hutt (Wellington) to the Bay of Islands (Northland).
Establishment:
Cameron et al. (1989) - despite the original extremely small gene pool [see Cameron et al. (1989) entry in ‘Import notes’ section], C. gurneyi is now widespread throughout New Zealand.
Impacts on target:
Cameron et al. (1989) - there have been no studies of the impact of C. gurneyi on populations of the three major pseudococcid (mealybug) pests in New Zealand: Pseudococcus longispinus, P. calceolariae and P. viburni [then called P. affinis - see taxonomic note in ‘General comments’ section]. However, in combination with the self-introduced parasitoid Tetracnemoidea brevicornis, it is likely to have considerable impact on P. calceolariae, at least in tree crops.
Cameron et al. (1993) - Coccophagus gurneyi is categorised as exerting “partial” control (defined as “additional control remains commonly necessary but…pest outbreaks occur less frequently”) over Pseudococcidae (mealybug) pests in New Zealand.
General comments:
Taxonomic note (24 February 2023) - Pseudococcus viburni is best known in earlier literature as Pseudococcus affinis (Maskell 1894) and P. obscurus Essig 1909, from which is derived its common name ‘obscure mealybug’ (Charles 2011). Cameron et al. (1989), for example, refer to it as P. affinis. However, Ben-Dov & Matile-Ferrero (1995) designated these names (and others) as junior synonyms of P. viburni (Signoret 1875).
References
Ben-Dov Y, Matile-Ferrero D (1995). The identity of the mealybug taxa described by V.A. Signoret (Homoptera, Coccoidea, Pseudococcidae). Bulletin de la Société Entomologique de France 100(3): 241-256 https://www.persee.fr/doc/bsef_0037-928x_1995_num_100_3_17152
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
Charles JG (2011). Using parasitoids to infer a native range for the obscure mealybug, Pseudococcus viburni, in South America. BioControl 56(2): 155-161
