Introduced wasp species are causing problems throughout the Waikato, particularly over the summer, according to Environment Waikato.
New Zealand has five introduced wasp species - the Australian paper wasp, German wasp, common wasp, Asian paper wasp and Scoliid Wasp. They flourish in New Zealand, as there are no natural predators, winters are relatively mild and there is a plentiful food supply.
Wasps pose a danger to viticulture and forestry workers, camping grounds and recreational areas, honeybees, by raiding hives and diminishing food supplies and the environment, consuming large numbers of native insects which are an important food source for many of our native species including kaka, tui and geckos.
An average wasp nest can produce between 1,000 – 2,000 queens each season. Queen wasps will fly up to 70 km in search of a nest site but most won’t establish nests the following spring. Nearly all the worker wasps – the most visible - die before they are three weeks old.
Common and German wasps, the main concern in the Waikato, are slightly bigger than a honey bee with smooth bodies, a black head and thorax and 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.
The Australian paper wasp and the Asian paper wasp are found in the Region but the extent of their populations is unknown.
In the last five years, wasp numbers have increased in Auckland and the Waikato, building their nests underground, in sunny spots, along banks, attached to walls, plants and under the floor and eaves of houses.
Environment Waikato provides advice and referral on wasps. They can be destroyed using powdered insecticides (from most garden centres and farm supply stores. The smaller, above ground paper wasp nests can usually be controlled using household fly spray. Paper wasp nests hanging from a tree can be enclosed with a plastic bag and placed in the freezer for at least three days to kill the wasps.
The Council also has advice to avoid stings from wasps:
- Stay calm. Don’t flap your arms about or jump around. 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.
- When you are walking through the bush in spring or summer time, be wary of where you put your feet and what you brush your pack on.
- Wear light coloured clothing. Wasps, as with honey bees and bumblebees, will direct their attacks against dark coloured objects (particularly blue) when disturbed.
Cold pads and antihistamine can help with stings, but stings on the face, neck or mouth should have medical advice as swelling can block the throat.