“Spicy Sky Raisins” – Introduced Wasps

Department of Conservation —  20/12/2022 — 2 Comments

Summer is the best. We all know that!

Our good summer vibes stem from getting amongst some classic kiwi activities like BBQ’s, BYC (backyard cricket), beaching and going for a hīkoi up in the hills. But, all these amazing summer activities can be easily ruined by the tiny but menacing “spicy sky raisins”, introduced wasps.

In Aotearoa we have several native wasps. These ones are the goodies. We like them. – In fact, because these wasps have evolved here, they live harmoniously with nature and have never become a nuisance.

What we’re really talking about is the five species of wasps that were accidentally introduced and are classed as pests (German and common wasps, and three species of paper wasp).

It’s an absolute shambles, putting all that hard work in behind the grill, to then serve up your meal to family and friends, garnished with a serving of winged, stinging (some of them), gate-crashing wasps who seem to help themselves to the feast too.

Or

You’re out at the beach enjoying the sun and warm weather, when your chilled vibes are interrupted by a menacing buzz of a few spicy sky raisins, forcing you to shift from your prime spot and relocate to some other (inferior) spot to avoid the terror.

Whangapoua Harbour.
📷: Evans, Shellie

Or

You’re going for a nice summer stroll in the hills, just as you start to think “This is amazing, could this get any better” you hear a low buzzing sound. A cold shiver runs down your spine and before you know it you’re pale-faced in full sprint mode running away from an angry mob of wasps intent on causing harm to you.

Jean on the Milford Track in Fiordland National Park, New Zealand.
📷: Strother, John T

The truth is that apart from these critters being annoying and menacing, with the always looming threat of being stung, these introduced wasp species are a significant pests which harm our native birds and insects, and are a threat to our health and recreation.

Fun Fact: The venom from a wasp sting contains several toxins that can cause a hypersensitive or allergic reaction in some people.

Wasps are a major problem in some beech forests too, where they consume massive amounts of honeydew – a food source for native birds, bats, insects and lizards produced by a native scale insect.

Wasp feeding on honeydew
📷: Edwards, Eric

They also eat huge numbers of native insects and have even been seen killing newly hatched birds. By eating so much, they upset the natural food chain of the forest.

Seasonally, in some beech forests there are an estimated 12 nests, or 10,000 worker wasps, per hectare. This makes the total combined body-weight of wasps in these areas higher than the weight of all native birds, stoats and rodents, put together.

Controlling wasps

The approach to wasp control depends on whether wasps are a nuisance over larger areas of land with several nests or are just a pain with one or two wasp nests in an urban area. 

To control wasps over a large area with several nests use Vespex.

Vespex is a protein (meat-based) bait, containing the insecticide fipronil, which is deployed from a bait station. Wasps take the bait back to their nests to feed their young, wiping out the nest.

Because it’s protein based wasps find it delicious and it’s not at all attractive to bees.

We like bees. Wasps not so much.

Bait stations are placed high above the ground, so that other protein attracted insects, such as wētā can’t get to it and can’t get into it.

Wasps taking bait
📷: Ruark, Joe

Vespex can be purchased from Merchento, but you need to become an approved user.

Find out more here.

If you have one or two wasp nests near you, but don’t know where they are, go searching on a sunny day, near dawn or dusk, the low light angles will highlight the flight path as wasps enter and leave the nest.

You can place a dessert spoonful of insecticide at the nest entrance after dark when the wasps have stopped flying.

Wasps on nest
📷: DOC

Worker wasps flying in and out will spread the powder into the nest and the colony usually dies within a day. If activity continues repeat the treatment until wasp activity ceases.

Hardware and garden stores supply a range of insecticides suitable for this method. These include Wasp Killer Dust and Permex Insect Dust, which have permethrin as the active ingredient, and Rentokil Wasp Killer.

Follow the safety instructions supplied with the insecticide.

Get control of the wasps in your area and keep the summer good vibes spicy sky raisin free.

2 responses to “Spicy Sky Raisins” – Introduced Wasps

  1. 

    Is there any funding lines to assist with the cost of Vespex… $66 registration fee, $210 for 1.5 Kgs of Vespex… so as we can get started and assist with the reduction of this pest..?? Mark Knight, Maitai Whare Iti, Nelson

  2. 

    They are a nightmare when hunting in the roar, all you can hear is the buzzing of the wasps. Be good to have them genetically bred to extinction in NZ

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