John Berry on Wasps

By John Berry

I went out specifically to poison a wasp nest on a friend’s place today. I was hoping to get some live-action photos to go with this article, but they were aggressive from about 20m and very defensive within five. It is by far the biggest nest I’ve seen in several years and is definitely not one of this season’s – they just don’t get that big within one year. Rather than take photos I ended up just sprinkling it with carbaryl. I was able to get it directly in the hole and it will quickly spread right throughout the nest and it will be dead within a few hours. 

Queen wasps hibernate in places such as wood piles over the winter and start their nests in places like old mouse holes. They have to raise and feed their larvae themselves and a lot of these early workers are very small. The nests generally get the size of a soccer ball over the summer and in autumn they start rearing queens and drones which mate and then the whole cycle starts again.

In New Zealand sometimes nests survive the winter, usually by eating your bees, and these nests can get truly enormous. Wasps can sting as many times as they like. 

All wasp nests are potentially dangerous and the bigger the nest the worse the danger. Individual wasp that are out foraging, or even raiding a beehive, are generally not aggressive.

Small nests will react to stimulation like being walked on, but the truly large nests – some which must get close to a cubic metre – are at another level entirely. The first intrusion into their territory acts in a similar way to cocking a trigger and the second intrusion leads to the trigger being pulled. This is why when a nest is disturbed by a group of trampers, it is the people further back that suffer the consequences.

I find that provided I walk quietly and move slowly I can generally dust an entrance without any protective gear at all and then quickly but quietly leave the scene. If however the entrance is hard to access, such as under a pampas grass or in a confined roof space, you need all the protection you can get, with a minimum of two layers of clothing.

A recent find of a large wasp nest by John Berry, at least 1m in length.

Wasp stings are chemically quite different from bee stings and I find them much more painful and long lasting. Even with full bee gear on some stings can get through. When being attacked I have found the two best options are to, one, freeze (this is what I generally do if I have all my gear on and the majority of them soon lose interest) or, two, run like hell dodging around as many trees et cetera as possible. This is the preferred option when you have underestimated the need for protective clothing. 

Standing in one spot, waving your arms, screaming , while trying to squash them is not a good option. 

Wasps are a major predator of bee hives. Before varroa they were probably the major cause of death, worse even than PPB (that’s ‘piss-poor beekeeping’ to the uninitiated) and are still a serious problem. As a general rule if the bees are doing alright you don’t get too much problem with them, but as the season starts to wind down in the autumn and resources for all insects dwindle you will start to see attacks. Bees can, and do, defend themselves and attacking a hive comes at a cost. They will always pick on the weakest first, but as the season gets progressively colder they get braver.

Wasps can operate at lower temperatures than bees. They eat the bees, they steal the honey and they stop the bees from wintering down properly and the continual fighting means that bees that should have lived all winter can die from stress and even when colonies survive the attacks they can come into spring extremely weak. Under prolonged attack, bees can lose the will to resist and you will see wasps freely entering hives. You can tell when wasps have been stealing honey by the way frames of honey are pockmarked with holes. Bees are much more methodical and work from an edge when consuming honey. 

I had some apiaries that never had a wasp problem, some that had it occasionally and some that had a major problem every year. In the past you had five options.

The Five Traditional Options

One. Move the hives out for the winter. 

Two. Put in entrance blocks. I preferred a very small gap of about 15mm on either side of the entrance. This allows for some through ventilation, but hives will get damp inside. This however is better than being dead. There are some fascinating and often quite complicated designs of entrance blocks, some of which work pretty well, but the main secret is to put the blocks in before they are needed. They help, but if the attack has already started they often don’t help enough. 

Top feeders to beehives can prove effective wasp traps in John Berry’s experience, but there are far better ways to manage the problem.

Three. Hunt down and poison the nest. I had one apiary where we would regularly get up to 30 nests within 200 m of the hives and we never got all of them. Tracking down nests can be very time-consuming, but it was still one of our most common options and I have found many hundreds over the years. Generally speaking, wasps fly in a straight line when returning home. They will normally be in a weedy rough corner or bank. I have found them in the middle of pasture, but that is very unusual. 

Four. Genetically selecting hives that show resistance to wasp attacks. It would be fair to say that stroppy black bush bees generally show plenty of this, but it is absolutely possible to breed the same trait into beautifully quiet bees. If you do end up with a bit of a wasp disaster then always take advantage of it by assessing the survivors for possible breeders. 

Five. Trapping. I have tried quite a few over the years with mixed success. I think the main trouble is that in many cases you are just dealing with such a huge biomass that you can only trap a small percentage. Having said that, one of the most successful methods I have ever found was to just leave top feeders on for the winter. For some reason the wasps seemed to go into them and then not be able to get out.

A Modern Solution

In recent years other options have become available and that is poison baits, namely Vespex (with the active ingredient fipronil) but also market newcomer Hawkeye. They are expensive and don’t always work first time, but they have been an absolute game changer. I put Vespex out anywhere I see wasps and for those apiaries that always have a problem I will start putting them out after Christmas, way before I have any problems. You will kill the nests while they are still small and you will be doing both your bees and the local ecosystem a huge favour.

The first time I used a bait was in an apiary that had been attacked by the same nest for two seasons. I knew exactly where it was but was not prepared to abseil 50m down an unstable red metal cliff. There was a hive that had already been killed that autumn so I removed all the frames and simply placed the container of poison inside the empty hive. Problem gone. On another occasion I turned up at an apiary where no damage had been done, but there were literally thousands of wasps flying around and the bees would not leave the hives. Put out some baits in proper bait holders and two days later not one to be seen.

German wasps (Vespula germanica) have been here since the Second World War and common wasps (Vespula vulgaris) came in much later. It is thought that German wasps are worse for beehives, but they are both pretty bad and the only real difference I see is that common wasps are even more aggressive around the nest. It’s not an infallible method, but if the wasp has  black dots that are not connected to the black stripes then it’s probably a German wasp.

You can still kill nests the old-fashioned way by upending a beer bottle full of petrol down the hole . Don’t light it (unless you really, really want to). Carbaryl is dodgy stuff which is why it is no longer available, but it can still be found in grandad’s spray cabinet. I can’t recommend using it, but a heaped teaspoon works every time. Pyrethrum wasp powder is remarkably ineffective and squashing them with the tin often has more effect. Squashing Queen wasps in the spring is probably a waste of time as there are thousands of them, but it does make you feel better.

Vespex poison baits can help beekeepers remove their wasp problem overnight in the right situation (note: bait stations should always be placed in appropriate locations to maximise their effectiveness and reduce risk to other species).

There was, and for all I know still is, a market for wasp lavae in Japan for those keen to die… I mean diversify. (Editor’s note: indeed there is, we profiled a wasp hunter in February 2024 in Wasp Hunter Needs Beekeepers Help). At a pinch, fly spray will kill a small nest but will probably take several visits and several cans. It is not suitable for large nests. For difficult to get at nests you can pack powdered insecticide into the end of a piece of hose and then blow it in the entrance. You can get compressed air versions of this if you want to get into serious wasp control.

Wasps are a public nuisance and for some reason the public think that beekeepers are responsible for dealing with them. I have never charged for destroying a nest in someone’s garden, but I probably should have. If I was doing it for a living rather than a public service I would want at least $300 before I climbed fully togged up into a confined roof space to kill a nest before it kills me and before I expire from heat exhaustion. Better make that $500. 

Biological controls have been imported over the years, but unfortunately have had little effect. Paper wasps don’t attack bees, but probably do compete with other wasps for a lot of the same food and probably help a little bit. 

They are amazing, beautiful and complex social insects which unfortunately cause immense damage to apiculture, viticulture and our native ecology.

Show them no mercy. They won’t show you any.  

Know where there is a significant German wasp nest? John Eason would like to know about it. See this article for more information.

John Berry is a retired commercial beekeeper from the Hawke’s Bay, having obtained his first hive in 1966, before working for family business Arataki Honey and then as owner of Berry Bees. He now keeps “20-something” hives.