Unless you physically disturb a wasps’ nest, the wasps are very unlikely to cause any problems, so leave the nest alone, if it is not inconveniencing you. It will naturally die out at the onset of winter, and will never be used again.
If the nest entrance is in an inconvenient position and the wasps are a nuisance, the best way to destroy it depends on circumstances. Seventy percent of nests are underground. If you can see the entrance hole and it’s within reach, spray it with a jet of wasp nest destroyer foam. These sprays can be bought from any hardware or farm shop and are designed to direct an accurate jet to a distance of three metres or more, allowing you to spray the nest entrance from a safe distance, beyond the edge of the danger zone.
If the nest is in a bush, tree or roof space, the same method can be employed, providing you can get a clear view of the nest entrance hole. If not, then a pest-control officer may have to be called to do the job for you. This could cost you at least £60 at current rates.
If dealing with the nest yourself, spray it at dusk if possible, as most of the wasps will have returned from their foraging trips.
Although the first spraying should kill off the queen and most of the worker wasps, repeat sprayings may be necessary, as a few wasp larvae will survive to hatch out later.
If the nest is in an attic or roof-space, leave it in situ, even if you or a pest-control officer have killed the wasps. The nest material is never used again and will block the hole, so next year’s queen wasps will not be able to get in to create a new colony. As an added bonus, the nest material (a papier mache-like substance called carton) is an excellent insulator and not very flammable, so can help reduce heat-loss from your roof.
How to deal with wasps buzzing around your picnic or barbecue
Wasps can be a real nuisance when you’re trying to enjoy a meal outside. Luckily, they stop flying at dusk, so you won’t be plagued with them during evening barbecues, but how do you stop them pestering in the daylight hours? Here are a few tips:
- If you’re well organised, search for signs of wasps’ nests early in the year, to prevent big colonies forming in and around your house and garden. Queen wasps emerge from hibernation in March or April and can be seen flying slowly around roof edges, garden sheds, bushes and lawns, as they search for possible nest sites. From May to early June the queens will have established embryo nests. These are easily seen, hanging in attics, roof spaces and sheds, where they appear as sandy brown or grey coloured spherical objects, about the size of a golf ball. At this stage the nest can easily be destroyed, by putting a small plastic bag around it and pulling it off its support. The queen may be inside it, but there will be no workers until the first ones emerge around the beginning of June. If the queen is not at home, she will be foraging for wood pulp, water, nectar or insects as food for her larvae. In this case, try to find the hole through which she enters to access her nest, then block it up. Underground nests will be less easily found, until later in the year, when streams of workers entering and leaving will make it obvious. Deal with such nests as described above.
- Even if you are confident you’ve found all possible nests in your house, outbuildings and garden, you may still have a wasp problem – especially in ‘good’ wasp years. This is because foraging wasps will fly for up to half a mile in search of food.
- To reduce the numbers of foraging wasps, you can resort to using good old-fashioned wasp traps. Essentially these are water-filled containers, baited with something attractive to wasps. In theory this can be a smelly fish, such as sardine, or something sweet, like strawberry jam. In practice, meat and fish soon start to rot and also attract flies, so sweet, fruit flavoured foods are better. During my research, I found that ginger syrup was the most effective attractant, but other good alternatives include mixtures based on cider or beer (wasps are attracted to the smell of alcohol, as they associate it with sugar), jam, honey, or apple vinegar. Put the attractant in a jam jar, then half-fill it with water and shake it to mix. Punch a hole in the lid of the jar, just big enough to allow a wasp to crawl inside, then add a drop or two of washing-up liquid. This reduces the surface tension of the water, so any wasp that drops in sinks immediately and drowns quickly. Then hang the jar from a branch or hook, relatively close to your eating area. Empty the trap regularly and replenish the attractant. Set more traps if necessary. This method will reduce the numbers of wasps, but it may take a while to show, as an average colony can produce up to 30,000 wasps in the course of the summer, and your wasps could easily be coming from more than one nest.