We have several thousand species of native wasp; they are all solitary and don’t really bother us. There are five species of introduced wasp; these are all social wasps, three species of which are the paper wasp, and the other two are the German and the Common wasps (of the Vespula genus). NZ has the highest concentrations of Vespula wasps in the world. These Vespula wasps are the ones that caused us so much pain and terror as kiddies when growing up. On the positive side they are effective predators and kill many insect pests. On the other, they also kill harmless native insects and compete for resources with many native species of insects and birds.
Every year most beekeepers complete the Colony Loss Survey and wasps feature in the top five causes of death of a hive in NZ. This is interesting because most other beekeeping countries do the same survey, and no other lists wasps. I’ve lost several hives to wasps last year; but in the South Island the losses are far higher especially in and around the beech forests. I don’t mind paper wasps so much as they don’t bother honey bees, but they do eat caterpillars (especially Monarch butterflies), crickets, flies, spiders and some native insects. Wasps are insectivores and get their protein from insects. They also need carbohydrates and get their sugars from nectar and ripe fruit, and so become a major pest for orchardists and gardeners.
Paper wasps are also known as umbrella wasps because their nests are quite distinctive and resemble an upside-down umbrella. They are less aggressive and have smaller nests than the Vespula wasps and can’t be killed with a bait or lure. Once you’ve found the nest you can spray them with a wasp spray from a hardware shop; these spray a jet of foam about 4m and cost about $20. Or you can use fly spray and run faster. It is best to kill a wasp nest at dusk or dawn when all the wasps are home.
Vespula are easier to deal with, but they are more aggressive, and they can have much larger nests, which are usually underground. Both Vespula wasps (German and common) can be managed in the same way. To find a wasp nest, put a small amount of cat food or tuna on a plate. Wait for 20 minutes and the wasp will usually have returned to the nest and brought back her sisters, so there will be wasps coming and going back home. The cheapest way to eradicate Vespula is to upend a bottle half filled with petrol into the entrance hole of the nest after dark. Leave the neck of the bottle in the hole and the fumes will kill the whole nest. DO NOT LIGHT IT. Or you could sprinkle wasp powder in the hole. The safest way is to call your local pest control. My friends call me when they have a wasp nest, as I have the correct PPE, I know what I’m doing, and I’m used to getting stung. I also use Vespex, which is a poisoned bait that wasps take back to their nest, which ensures that the whole nest dies. You do have to be registered to use it, and it must be stored frozen and it can only be used when wasps are in their protein collecting phase in autumn. Hawkeye is a bait that attracts Vespula wasps any time of the year (during both protein and carbohydrate phase), it can be stored at room temperature and it is less toxic to us and pets. Hawkeye is also available as a lure.
A trap attracts and kills individual wasps. You can buy wasp traps from most hardware stores along with a lure or attractant. You can make your own attractant with jam, vinegar and water, it’s important to add a bee deterrent (vinegar) or you’ll kill bees too. To make a cheap trap, cut a plastic soft drink bottle two thirds of the way up and then upend the top part into the bottom. Vespex and Hawkeye are available online.
Fun Fact: Bees are basically vegetarian wasps; they shared a common ancestor 135 million years ago. Bees now get their protein from the pollen in flowers which they co-evolved with.
References& more info
www.teara.govt.nz
www.landcareresearch.co.nz
www.doc.govt.nz
The Vulgar Wasp; Professor Phil Lester
Ken Brown
Apiculture Tutor with Land Based Training Ltd.
