Target pest: Eriococcus coriaceus (Hemiptera: Eriococcidae), gum tree scale
Agent introduced: Orcus chalybeus (Coleoptera: Coccinellidae) = Halmus chalybus (Boisduval), steel-blue ladybird
Cameron et al. (1989) - in 1899 O. chalybeus was imported from Australia to control S. oleae. In 1905 it was imported from Australia to control Eriococcus coriaceus (gum tree scale).
Cameron et al. (1989) - in 1899 O. chalybeus was released throughout New Zealand to control S. oleae. In 1905 it was released in near Timaru, South Canterbury, South Island from an Australian importation, to control Eriococcus coriaceus. In that same year it was also redistributed from Auckland, North Island, populations to South Canterbury, where the problem with E. coriaceus was most severe.
Cameron et al. (1989) - in 1908 it was reported that O. chalybeus had apparently established from the 1905 South Canterbury releases [see Cameron et al. (1989) entry in 'Release details' section] but was never recovered there in great numbers. In 1925 it was reported as having failed to establish in Canterbury. In 1936, O. chalybeus was known to exist in the Auckland province. It is now known from Northland, Auckland, Coromandel, Taupo, Tauranga and Gisborne in the North Island, and Nelson in the South Island.
Impacts on target:
Cameron et al. (1989) - Orcus chalybeus is usually only found in the northern, warmer parts of New Zealand and consequently has very little effect on E. coriaceus.
Impacts on non-targets:
Cameron et al. (1989) - in 1925 O. chalybeus was reported as proving useful against Asterodiaspis sp. (pit scales, pests of oak trees) in Auckland. It has also been reported feeding on Aonidiella aurantii (citrus or California red scale) and Quadraspidiotus perniciosis (San JosÃ© scale) (both economically important pest species) in New Zealand.
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.
Tillyard RJ (1923). History of the introduction of beneficial insects into New Zealand. Proceedings of the Pan-Pacific Science Congress, Australia, 383-390.