Biocontrol introduction

Target pests:

Aphids (Hemiptera: Aphididae)
General pests

Agent introduced: Scymnus loewii (Coleoptera: Coccinellidae), Loew's ladybird

Imported:

1941 (accidental introduction)

Import notes:

Martin (2019) - native to North and Central America, S. loewii is an accidental introduction in New Zealand, first detected in this country in Auckland in 1941.

Release details:

Bioforce 2020 (accessed 23 Feb 2026), Nielsen et al. (2025) - inundative releases of S. loewii, as the commercially available product "Dusky Ladybird", for augmentative biocontrol programmes, are ongoing.

Establishment:

Martin (2029) - Scymnus loewii is established in the North Island.

Impacts on target:

Martin (2019) - adult and larval S. loewii eat mealybugs, aphids and probably other insects. It is present in northern New Zealand where it may contribute to the biological control of some species of mealybugs and other insects in the home garden and commercial crops.

Bioforce 2020 (accessed 23 Feb 2026) - Scymnus loewii is commercially available in New Zealand, under the product name "Dusky Ladybird", for use as an augmentative biocontrol agent in Integrated Pest Management programmes. [Augmentative biocontrol involves the mass-rearing and periodic inundative release of natural enemies to manage pest populations on a short-term basis.] It is primarily an aphid predator (it is a known predator of aphids in the genera Aphis and Myzus), however it will also feed on a large variety of alternative prey, including psyllid and whitefly eggs, and the eggs of larger insects such as butterflies and moths. Both adults and larvae feed on the eggs and juveniles of the tomato/potato psyllid [Bactericera cockerelli]. It appears to survive well in glasshouse grown capsicums when feeding on the [green] peach aphid [Myzus persicae] and colonises cucumber as well. The use of S. loewii as a commercial augmentative biocontrol agent is still experimental and it is currently uncertain which crops it will colonise and which pests it will prey on.

References

Bioforce (2020). Bioforce Ltd https://www.bioforce.co.nz

Martin NA (2019). Interesting insects and other invertebrates: Loew’s ladybird - Scymnus loewii. New Zealand arthropod factsheet series number 172 https://interestinginsects.landcareresearch.co.nz/taxa/4b2ef448-c61f-419e-ab29-cc8603276896

Nielsen M-C, Barratt B, Thompson C, Chhagan A, Puketapu A, Horne P, Vereijssen J (2025). Augmentative biological control of invertebrate pests in Australasia: experiences from down under. Biological Control, Vol. 210, November 2025, Article No. 105895 https://doi.org/10.1016/j.biocontrol.2025.105895