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Biocontrol introduction

Target pest: Panonychus ulmi (Acariformes: Tetranychidae), European red mite

Agent introduced: Galendromus occidentalis (Parasitiformes: Phytoseiidae) = Metaseiulus occidentalis, Typhlodromus occidentalis



Import source:

North America via Australia

Import notes:

Cameron et al. (1989) - an organophosphorus-resistant strain of G. occidentalis was imported into New Zealand (as Typhlodromus occidentalis) from Australia in 1976, following its successful introduction into that country from North America in 1972. It was initially reared in quarantine and later laboratory-reared in Auckland. This species was already present in New Zealand prior to the release of the organophosphorus-resistant strain.



Release details:

Cameron et al. (1989) - the organophosphorus-resistant strain of G. occidentalis was released at Nelson, Waimate, Central Otago and Canterbury (Loburn and Lincoln) in the South Island, and at Hastings, Hawke’s Bay in the North Island.


Cameron et al. (1989) - the organophosphorus-resistant strain of G. occidentalis became established in Central Otago, Canterbury and at Hope, Nelson. In Canterbury and Central Otago this strain has persisted in orchards at very low levels.

Impacts on target:

Cameron et al. (1989) - predatory phytoseiid mites (G. occidentalis, Phytoseiulus persimilis, Neoseiulus fallacis) were introduced into New Zealand primarily for the control of Tetranychus urticae (two-spotted mite) and only to augment control of P. ulmi by the biocontrol agent Typhlodromus pyri. Although established in some regions of New Zealand, especially in the south, G. occidentalis does not provide the high level of phytophagous pest mite control reported from North America. In Canterbury, populations of G. occidentalis established in berryfruit crops have now been largely replaced by another introduced predatory mite biocontrol agent, Phytoseiulus persimilis. The release programme for all three phytoseiids has contributed little to the control of P. ulmi.


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.