Introduced wasp species are causing a number of problems throughout New Zealand. New Zealand provides favourable habitat for wasps, as there are no natural predators, winters are relatively mild, and there is a plentiful food supply.
On this page: what they look like, where they're found, responsibility for control, controlling wasps, reduce the risk, useful contacts, other publications
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Wasps pose a danger to:
- vineyard and forestry workers
- honeybees, by raiding hives and diminishing food supplies
- picnickers and holiday makers incamping grounds and recreational areas
- the environment. Wasps consume large numbers of native insects which are an important food source for many of our native species including kaka, tui and geckos.
What they look like
There are five introduced wasp species in New Zealand, the common wasp (Vespula vulgaris), German wasp (V. germanica), Australian paper wasp (Polistes hummulis), Asian paper wasp (P. chinensis) and Scoliid wasp (Radumeris tasmaniensis).
Common and German wasps
Common and German wasps are the main concern in the Waikato region.
- are slightly bigger than a honey bee with smooth bodies (honey bees have hairy bodies)
- have a black head and thorax (middle segment of the body)
- have yellow and black stripes on the abdomen.
The German wasp has separate black dots on the yellow rings on its back and has a yellow ‘pronatal’ band just behind the head. The ‘pronatal’ band on common wasps is parallel sided and the dots and black rings on its back are fused.
Paper wasps are smaller than the German and common wasps. The Asian paper wasp is yellow and black with tan coloured legs. The males are smaller and more yellow than the females. The Australian paper wasp is a reddish brown colour and is smaller again than the Asian paper wasp.
The Australian paper wasp and the Asian paper wasp are found in the region but the extent of their populations is unknown.
Scoliid wasps are native to Australia and were first recorded in New Zealand in February 2000. Female scoliid wasps are up to three centimetres long, with a large, robust body. The head and thorax are dark coloured, and the abdomen has orange and black stripes. Male scoliid wasps are smaller, up to two centimetres long.
Scoliid wasps are a threat to our native beetles and it's important all sightings are reported. Although they are unlikely to be found in the Waikato, people using beaches and sandhills should keep an eye open for these large, hovering and burrowing wasps.
Median wasps are established in several countries which have a climate similar to that of New Zealand. This species of wasp has only been recorded in the Northern Hemisphere where it is found from England, across northern Europe, Russia and Asia to Japan. Median wasps have less yellow than other New Zealand social wasps, and have a distinctive reddish-brown appearance with brown tinted wings.
A male median wasp was found in a house in Raglan and handed into the Ministry of Agriculture and Forestry (MAF). No other median wasps have been found within New Zealand, so it is not known if a locally established population exists or whether this particular wasp was an isolated occurence.
Find out more about scoliid and median wasps by checking out the Ministry of Agriculture and Forestry's factsheets in PDF format below.
Scoliid Wasp Factsheet
(439 kb, 62 seconds to download, 56k modem)
Median Wasp Factsheet
(250 kb, 35 seconds to download, 56k modem)
Where they're found
In the last five years, wasp numbers have increased in the Auckland and Waikato regions, and they've invaded southern parts of the North and South Islands. Wasps build their nests in a variety of places, often choosing sunny spots:
- along banks
- attached to walls
- attached to plants
- under the floor and eaves of houses.
The best time to search for a wasps nest is on a sunny day, preferably at dawn or dusk. This time of day is good because the low light highlights their flight paths as they go in and out of their nests.
Responsibility for control
Waikato Regional Council does not have an eradication programme for wasps as they are not considered a major pest in the Waikato region. However, if Waikato Regional Council receives a complaint about a wasp nest, we can make the relevant landowner take steps to control the pest on his or her property.
Waikato Regional Council can provide advice and a referral service to interested parties. We also contribute to nationwide research programmes concentrating on biological control and ‘in-flight’ baits.
Problem wasp nests on district or city council reserves and accessways should be reported to the appropriate council, which will arrange for the nests to be destroyed. Nests on Department of Conservation (DOC) land should be reported to the nearest DOC office or visitor centre.
Being proactive about wasp control will help protect you and your family from wasp stings and attacks. The most successful way of reducing a local wasp population is to find and destroy all the nests.
Wasps will most often search for food within 200 metres of their nest. If you can kill all the nests within 200 metres of the trouble spot, you should significantly reduce the wasp population.
Look for flight paths at dawn or dusk on warm, sunny days when large numbers of wasps will be leaving or returning to the nest. Attract the wasps using a plate of cat food and, as they land, sprinkle with flour so you can see and follow them until you find the nest.
Always take caution when destroying a wasp nest. Wasp control is best done at night or twilight on cool days when they are generally inactive. Use a bee keeper's suit when controlling large nests. If you are not confident about approaching a wasp nest, contact a local specialised pest control agency (listed in the yellow pages of the telephone book) or contact us for more information.
Suitable insecticides available from hardware and garden shops include:
- BLITZEM! Wasp Killer Nest Destroyer (Yates NZ Ltd)
- Permex Insect Dust (Flybusters)
Follow the directions on the container.
You should be able to control smaller paper wasp nests using household fly spray. Small paper wasp nests that are hanging from a tree or branch above ground can be enclosed with a plastic bag and snipped from the tree. Place the bag and nest in the freezer for at least three days to kill the wasps, and dispose of them in the rubbish.
A wasp parasatoid (Sphecophaga vesparum) has been trialled by Manaaki Whenua - Landcare Research. The parasite hatches in spring, in time to invade wasp nests and destroy immature wasps. The parasites have established in two sites in New Zealand but have not reduced wasp numbers significantly.
Microbial pathogens (such as fungi, bacteria and viruses) are currently under investigation by research teams from Landcare Research and AgResearch.
Reduce the risk
If you are being annoyed by a wasp, stay calm and move quietly away. Wasps can be attracted to food. If you’re eating and the wasp won’t go away, put your food down and quietly move away from it. Wasps are unlikely to chase after you unless you have disturbed a nest.
Watch out for wasps and their nests when walking through the bush in spring or summer time, particularly if you are in honey-dew beech country. Reduce the risk of wasp stings by wearing light coloured clothing. Wasps (as with honey bees and bumblebees) tend to attack against dark coloured objects (particularly blue) when disturbed.
Most people react to a wasp sting with a raised, itchy, painful swelling. However, about 10 percent of people are allergic to stings and a small number people will have a severe allergic reaction, becoming unconscious in some cases.
- Cold pads and antihistamine cream will help reduce pain and swelling.
- If the sting is on the neck, face or in the mouth, tell somebody, take an antihistamine tablet when possible, and seek medical advice immediately. Stings in these places can cause swelling in the throat, cutting off the air supply to the lungs.
- If there are multiple stings, or the victim shows symptoms of nausea or shock, seek medical advice immediately.
When visiting bush or beach areas always make sure you take a first aid kit that includes antihistamine cream and tablets. Make sure you know if any members of your party are allergic to wasp stings before you leave. Ensure they carry medication at all times and that there is somebody else capable of assisting them if need be.
For additional advice and information on effective methods of control and to obtain pest control products, contact your nearest Biosecurity Animal Pest Contractor, local farm supply store or look under 'pest control' in the yellow pages.
Regional Pest Management Strategy
Waikato Regional Council Pest factsheets
'What makes a pest a pest? - A guide to Waikato's pest management future' download, order or pick for free from our offices.