Here we have collated some of the commonly asked questions about Vespex® and its use. Clicking on a question in the categorised list below will scroll you down to the answer to that question. Some of these questions will be very helpful when sitting the online assessment test to become an Approved User


Restrictions On Use


Product Description


Planning Your Wasp Control Operation


Operational Questions




Can anybody buy and use Vespex®?

No. In order to purchase Vespex® you need to be registered with Merchento as an approved user. You do not need to be an approved user to help out with a wasp baiting project, but the project must be directly supervised by someone who is an approved user. Currently, Vespex® is not available outside of New Zealand.


Will my approved handlers certificate allow me to buy Vespex®?

An approved handlers certificate is not the same thing as being registered as an approved user of Vespex®, which requires a product-specific approval as part of its stewardship requirements.


How do I become an approved user?

The process is being managed via an online testing and registration system, which is detailed on our Become an Approved User page.


Is there a cost to undertake training to become an approved user?

The training resources and assessment test are provided at no cost, but there is a registration fee of $58.00 (excl. GST) should you choose to become an approved user.


Can I get someone else to do the baiting for me?

We are working towards establishing a network of approved users around the country who will be able to provide a wasp baiting service.


What sort of wasps is it used for?

Vespex® is specifically designed for wide-area control of Vespula wasp species. In New Zealand, this includes both the common wasp (Vespula vulgaris) and German wasp (V. germanica). These wasps are also known as yellow jackets in some countries.


How does Vespex® work?

Wasps require protein to feed their growing larvae, and will  scavenge for good quality protein sources to take back to the nest. Vespex® utilises this behaviour through a formulation that includes both a highly attractive and palatable protein bait with a potent, but slow-acting insecticide. The wasps gather the bait from bait stations and take it back to their nests, where it is rapidly shared through the colony, including to the queen. It takes remarkably small quantities of Vespex® to destroy the whole nest.


Does Vespex® control those paper wasps that are attacking my monarchs?

Unfortunately not. Paper wasps (Polistes sp.) get the protein they need by hunting for living insects, especially caterpillars, and are not attracted to Vespex®.


Is this product really safe for bees?

Vespex® was designed to contain nothing that is attractive to bees. They simply have no interest in it. In addition to this, the stewardship controls applied to the use of Vespex® further reduce any chance of exposure to bees or other non-targets. Tests of beehives positioned beside areas where baiting with Vespex® has been undertaken show nil traces of the active ingredient.


Are my pets and livestock safe?

Yes. Vespex® has low toxicity to mammals and birds, and they would have to eat a large amount of bait to show any symptoms of poisoning. The active ingredient used in Vespex® is also found at much higher concentrations in veterinary products used to control external parasites on pets.  However, please note that dogs are also likely to be attracted to the meaty odour of Vespex® so make sure to keep your tub of bait out of their reach when thawing and transporting.


I have found a wasp nest that I want to kill. Can I put Vespex® in the entrance?

Vespex® is designed for use in bait stations only. There are a range of other products available that can be used to destroy individual nests that you have found.


Can I use Vespex® to target queens and very young nests in the spring?

Trials have shown that attempting to control wasps using a protein bait too early in the season is largely unsuccessful. Queens and early-season wasp nests have low requirements for protein, so the attractants in Vespex® are not particularly effective until the nests are at a critical stage in their development.


When is the best time to use Vespex®?

The timing for an effective baiting campaign is dependent on knowing when the wasp population in your area has a high demand for protein. This is determined via a simple activity testing procedure that is fully explained on the video in the information page. The threshold levels of protein foraging behaviour is rarely reached before mid January, and often in early February. You should also aim to bait wasps before their interest in protein begins to wane again from mid April.


What protein bait should I use for the wasp activity testing?

We recommend a plain raw protein such as fish offcuts, chicken, or rabbit meat. You can also use tinned salmon or tuna, but make sure these are canned in water (not oil) and that they are plain fish with no added flavours.


Do I need to put out signs when using Vespex®?

Signs are required wherever there is a public access point to the area being baited. Merchento can supply the correct signs, which meet all the legislative requirements for control on public conservation lands. The signs need to be out on display during the entire time the bait is in the bait stations (3-8 days).


Who do I need to notify before putting out Vespex®?

If you are undertaking a wasp baiting operation on private land, there are no notification requirements apart from signs at any public access points. If you are undertaking wasp baiting on land managed by the Department of Conservation, you obviously need their permission, but there is also an added requirement to notify the District Council and Ministry of Health.


How many bait stations do I need?

This depends on the size of area and the grid spacing you are using. The product label provides guidance on a suitable grid spacing for different sized treatment areas.


How much Vespex® do I need to buy?

Calculate this from the number of bait stations you are putting out. A 1.5 kg pail of Vespex® will service about 60 bait stations; a 600 g pot is sufficient for 24 stations.


How should I store Vespex®?

Vespex® needs to be stored frozen, and then thawed out prior to use.


How much freezer spaced is required?

A 1.5. kg pail of Vespex® has a similar volume to a 2L tub of ice cream.


Can I store Vespex® in my domestic freezer?

While Vespex®  is of low toxicity to people, it is always best practice to store Vespex® in a freezer that does not contain foodstuffs of any sort, and it must always be stored in its original container. If you must store it in a freezer that also contains frozen food items, then the original container of bait should be placed inside another plastic box with a tight-fitting lid to keep it well separated from the other contents of the freezer.  The outer box must also be labelled to clearly identify the contents and warnings. Additional freezer-proof product labels for this purpose are available on request.


What personal protective equipment (PPE) is required to use Vespex®?

Vespex® is a low risk product to people, and the only PPE required is appropriate protective gloves to prevent accidental absorption from prolonged handling. While there are various latex and synthetic rubber gloves that will afford protection, we recommend the use of nitrile gloves. These can be purchased directly from Merchento with your order (see our Baiting Accessories page for more details).


How much Vespex® do I put in each bait station?

Aim for 20-30 g per bait station. Vespex® is supplied with an appropriate quantity of disposable bait wells for the amount of bait you have bought, as well as applicator sticks. The bait wells have an indicator line on them and should be loosely packed up to this line to ensure you have at least 20 g in there. The bait wells are designed to fit nicely into the Wasptekbait stations, making both the laying and retrieval of bait a clean process.


Am I likely to get stung by wasps while putting out the bait?

In our experience, there is no greater risk of stings associated with the use of Vespex® than would normally be associated with walking around the same area. There is a much lower risk of stings than would be the case if you were treating nest entrances with an insecticide powder. However, anybody walking in a high-wasp environment should always be alert to ensure they do not inadvertently stand on a wasp nest, and should carry a wasp sting first aid kit. The Landcare Research wasp site provides excellent advice on wasp sting first aid.


Can I bait with Vespex® on the same day that I carry out activity testing?

We recommend against this because activity testing is best done around the middle of the day, so even if you were well above the wasp activity threshold, it would be the afternoon before you would be laying any Vespex®. The best time to lay Vespex® is in the morning to maximise the amount of time it is exposed to wasps on the first day.  You also need to allow at least 17 hours at room temperature for a 1.5 kg pail of Vespex® to thaw completely.


I would like to use Vespex® around my vineyard. What is the waiting period?

There is no waiting period. Vespex® is to be used only in bait stations and is never applied directly to any crop.


How long does Vespex® take to thaw, and can I use a microwave?

It takes about 17 hours for a 1.5 kg pail of Vespex® to thaw completely at room temperature. We do not recommend the use of a microwave, as these are also used for foodstuffs and the results can be uneven and can cause excessive heating, which has potential to reduce the effectiveness of the product.


Can Vespex® be re-frozen once thawed?

Yes. Vespex® is resilient to re-freezing and remains just as effective. However, while you can re-freeze bait that has been thawed for a couple of days in its original container, you should not attempt to re-use any bait that has been in bait stations.


I put Vespex® in a bait station above a wasp nest in my garden. Why hasn't it died?

Wasps tend not to forage on their own doorstep, so while you may have seen wasps in your bait station, they are probably not from that nest. This is one of the reasons we recommend using a grid of bait stations. The wasps from that particular nest may be foraging 200 m or more away. For the treatment of individual wasp nests that you have found in your garden, it is better to use one of the variety of insecticide powders that are available for this purpose, or get a professional pest controller in to deal with it. Vespex®  is better suited for reducing wasp problems over a wider area, rather than treating an individual nest.


Why do we need to clear bait from bait stations after 3 – 8 days?

This is one of the stewardship requirements for the use of Vespex® and must be adhered to for all operations. If the activity testing protocols were followed and the Vespex®  was put out at the correct time, then the bait has done its job on wasps within the week.  Beyond that, it is simply a latent risk to non-targets and freak events. Removing the bait from the stations after a maximum of 8 days ensures you achieve the benefits of wasp control while eliminating any ongoing risk from having an ecotoxin in the environment.


Can I just put Vespex® on the ground where I see wasps foraging?

No. Vespex® can only be used in bait stations that protect the bait from rain and pooling water. The stations must be a minimum of 70 cm off the ground, and raised to a minimum 150 cm if they are in an area with small children, pets or livestock. The bait stations should be at least 150 cm above the ground whenever it is practical to do so, and are easier to service at that height.


What do I do with the empty buckets and bait wells after the operation is finished?

All waste and materials contaminated with Vespex® should be securely bagged and disposed of at a council-approved landfill rubbish dump. You can take it there yourself or add it to your domestic rubbish collection service.


If you have other questions that were not covered above, please contact us.









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