It is that time of year when we start seeing black and yellow flying insects about. Yes, summer is wasp season.
There are essentially three wasp species in the UK. The two we see most often are the ones most people despise: the small ones the Common Wasp, Vespula vulgaris, and German Wasp, Vespula germanica. Both are definitely yellow and black. To all intents and purposes they look identical (if you really want to see the difference you’ll need to get up close and personal with them – most of you won’t want to).

(L) Common Wasp and (R) German Wasp
The queens (which are quite large) are out at the moment, starting their nests. In a few weeks time there will be the smaller workers around; these are the ones which are the pest of picnics and alfresco fun. Come September their job is done: they’ve raised new queens, who will mate and hibernate to repeat the cycle next year. So now the workers are at a loose end, and go hunting anything sugary. They’ll die off with the first very cold nights and frosts.
I understand just how annoying wasps can be, especially if you have a nest nearby. But please leave them alone! They are wonderful predators of other insects, which they need to feed their grubs. Without them we would be knee deep in creepy-crawlies – an average nest can consume several tons of insects in a single summer! They also have a minor role in pollinating plants.
By August/September a mature nest can have anything between 5000 and 25000 wasps in residence. This not something you want to go poking at even with a barge pole! Having said that the nests are amazing structures, built essentially from paper.

Wasp nest
Destroying a wasp nest is rarely worth the effort. The nests, once dormant, have low humidity and are essentially just paper. Removal of the wasp nest will not prevent future queens nesting in the same area. If pesticides are used on the nest then you may contaminate other areas to no purpose, and dust based pesticides tend to remain active for years, so might knock down future queen wasps, or indeed other insects that you’d want to keep.
The main thing that worries people about wasps is their sting. A wasp uses its sting for killing prey, but it can also use it very effectively for defending itself. An ordinary uncomplicated sting contains an absolutely tiny quantity of venom (a pinhead less than the size of the full stops on this page!) which is injected deep into the skin. So treating the skin surface with almost anything is going to have very little effect (except maybe psychologically). Probably the best course is to use an antihistamine ointment and/or an oral antihistamine tablet. But … if the victim becomes pale and feels unwell with giddiness and nausea, get medical advice immediately as a very few people can suffer anaphylactic shock which can be fatal.
The third wasp species you might encounter is the European Hornet, Vespa crabro, although these are very much less common that the two wasps mentioned above (despite years of nature watching, I have never knowingly seen one in the wild). And they are roughly twice the size of a a “normal” wasp and very definitely yellow and brown.

European Hornets
(If it is yellow and black, it’s a wasp. If it’s yellow and brown and large it is a hornet – and you’re very lucky to see it! If it is furry, it’s a bee of some kind.)
Hornets follow the same life cycle as wasps, but are generally more docile and less likely to sting (though you’ll know about it if they do get you). They are relatively uncommon, especially in cities, preferring wooded environments. The only thing against hornets is that they can predate honey bee colonies.
There are many other species of wasps around the UK. Most are solitary rather than social, often parasitic predators and they don’t sting. The other social wasps are generally uncommon, although the Norwegian wasp, Dolichovespula norvegica, is more prevalent in the north of the UK. There are also a couple of very uncommon non-native hornet species in the UK and there are scare stories about “killer wasps” in the media from time to time – generally these can be ignored (although this could change over time).
So unless you are one of the very few, unlucky, people who are allergic to their stings (when you do need to worry) the moral is: please leave wasps alone! If you have a wasps’ nest, treasure it! Wasps are wonderful predators, superb engineers and they’re mostly harmless unless you start threatening them.