Harlequin ladybirds threat to local horticulture
Infestations of Harlequin ladybirds in the Gisborne district could pose a threat to the horticulture and viticulture industries.
Originally from Asia, the invasive species was first reported to the Ministry of Primary Industries in Auckland in 2016 and has since been found in the Waikato, Bay of Plenty and Taranaki regions.
Locally it has been discovered in Te Karaka and Matokitoki Valley.
Harlequin ladybirds are a potential threat to the horticulture industry where they feed on pip fruit, causing blemishes on the fruit. They are known to cluster within bunches of grapes before harvest resulting in tainted juice.
They also pose a nuisance to humans where they swarm in buildings and houses. They can bite and cause allergic rhinoconjunctivitis.
They eat other insect species and compete for food resources, posing a risk to the biodiversity of our ecosystem. They will eat native ladybirds and also swarm in beehives over winter, requiring manual removal.
Due to the highly variable nature of Harlequin ladybirds they can be hard to distinguish them from other ladybird species. The M shaped markings between the head and abdomen and 2 small bumps on the rear of the back are their identifying features, they are also slightly larger than common ladybirds.
The larvae and pupae have a spikier skin than common spotted ladybirds.
If you find Harlequin ladybirds, please collect the specimen, photograph it and contact MPI’s free 24-hour pest and disease hotline on 0800 809 966.
MPI are tracking their spread and can provide information to growers about the insect and its management.
Photo: taken by John McLean