Skip to content

New biocontrol tools showing promise

Introduced Vespula wasps – the German wasp (Vespula germanica) and the common wasp (V. vulgari) – are generalist predators that attack a wide variety of arthropods, including honeybees, butterflies, flies, and spiders. Where they are invasive, these wasps have detrimental effects on normal ecosystem functioning, food webs, and the behaviour of native birds.

The wasps also have a significant impact on New Zealand’s beekeeping industry, with wasp damage regularly ranked as the third- or fourth-highest cause of colony loss in beehives. Together with their disruption of the enjoyment of the outdoors and recreational activities, and the health risks of stings, it is estimated that wasps cost New Zealand up to $130 million annually in damage and management.

Fortunately, new biocontrol tools are about to be released to control both types of wasp. The Tasman District Council, acting on behalf of the Vespula Biocontrol Action Group, applied to the Environmental Protection Authority (EPA) in September 2020 seeking permission for two new wasp biocontrol agents to be released in New Zealand: a beetle and a hoverfly, both of which parasitise the brood of the wasps within the wasp nest. The application was prepared and managed by Dr Bob Brown at Manaaki Whenua.

The EPA’s decision to allow the new biocontrol agents was notified on 16 February 2021, some five years after the first science was begun. This is a major milestone. The next steps are for Manaaki Whenua’s researchers to receive the agents into our insect containment facility for rearing and eventual release. 

The process for obtaining an EPA biocontrol approval is long and painstaking. A great deal of research was done to ensure the new biocontrol agents are completely specific to the target organism, do not attack any other organisms, and do not harbour any diseases or parasites that could attack them.

Many different groups are involved in any biocontrol initiative. For this one, stakeholders included South Island iwi, Department of Conservation staff, regional councils, the QEII National Trust, the NZ Landcare Trust, the Ecological Society of NZ, Federated Farmers, the Royal Forest and Bird Protection Society of NZ, the NZ Entomological Society, the NZ Forest Owners Association, Apiculture NZ, and District Health Boards. Public submissions were also heard.

Tags