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Biocontrol introduction

Target pest: Tetranychus urticae (Trombidiformes: Tetranychidae), two-spotted spider mite

Agent introduced: Neoseiulus fallacis (Mesostigmata: Phytoseiidae) = Amblyseius fallacis


1972, 1973, 1975

Import source:

Michigan, USA

Import notes:

Cameron et al. (1989) - an organophosphorus-resistant strain of N. fallacis was imported from Michigan, USA to Nelson in 1972, but none survived. Three additional consignments of this strain were sent to Lincoln, Christchurch in October 1973 and one more in 1975. The strain was successfully reared in quarantine to provide material for release.



Release details:

Cameron et al. (1989) - many thousands were released onto apple trees at Appleby Research Orchard, Nelson, South Island over three seasons (1973-76). During the same period releases were also made in the South Island at Loburn and Lincoln (Canterbury), Hope (Nelson), Waimate and Central Otago, and Hastings in the North Island. Mass propagation and release programmes were conducted at Hawke’s Bay in the North Island and Nelson and Canterbury during 1980-81.


Cameron et al. (1989) - Neoseiulus fallacis established in Canterbury, Central Otago and Hastings from the 1973-76 releases. The 1980-81 mass-rearing and release programmes in Hawke’s Bay, Nelson and Canterbury were unsuccessful at achieving widespread establishment in apple orchards in these regions.

Impacts on target:

Cameron et al. (1989) - mixed populations of phytophagous mites (T. urticae and the European red mite, Panonychus ulmi) were reduced in Canterbury following the establishment of N. fallacis from the 1973-76 releases. Trials in Canterbury and Blenheim, South Island, indicated N. fallacis numbers were most closely correlated with T. urticae populations in late summer. In a 1980 study, within-season control of phytophagous mites was achieved from direct releases of N. fallacis onto apple trees, but subsequent overwintering mortality was a problem and population increase was too slow in spring to prevent pest mite damage. Prior to the release and establishment of the field strain of Phytoseiulus persimilis against T. urticae [see the P. persimilis introduction entry], N. fallacis had become dominant in suppressing T. urticae populations during the 1980-85 period, but it has now been largely displaced by P. persimilis.


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.