Wasps at the table ruin every summer evening outdoors. Swatting makes it worse: a threatened wasp releases an alarm pheromone that draws others in.
There is another route, and it uses their own behaviour. Wasps are fiercely territorial and will not build a nest near another nest. Hang up a decoy nest and they see occupied ground, so they settle further away. No spray, no dead wasps, and bees and other pollinators are left alone.
The design is protected and has been on sale for fifteen years. It measures 30 x 220 x 220 mm, lasts about two years outdoors, and you fill it with empty plastic bags.
When do you hang up a decoy wasp nest?
Early in the season, in April or May. That is when the queen is looking for a nesting site, and that is exactly when deterrence works best. Hang it later and there may already be a nest nearby. One decoy covers a radius of about six metres, so a large terrace needs two, one at each end.
Where should you hang it?
Somewhere sheltered and clearly visible: under a canopy, on the veranda, by the shed or under a parasol. About two metres up. It has to be seen, so do not hide it in the planting.
What do wasps eat?
It changes through the season, and that explains why they only become a nuisance late on. In spring and early summer workers hunt protein for the brood, so meat, fish and other insects. Once the brood matures that job disappears and they switch to sugar. From then on soft drinks, fruit, jam and cake become interesting. August and September are therefore the busiest months at the table.
What are those big black wasps?
Dark insects that look like a wasp almost never are. Usually it is a carpenter bee, the large black bee with the loud hum, or a common wasp that looks darker in shade. They are rarely aggressive and almost never sting unprovoked. A decoy nest keeps these species at a distance too, without killing anything.
How quickly does a wasp colony grow?
A queen starts alone in spring with a nest of a few cells. By August that same colony can number thousands of workers. That is why the nuisance seems to appear suddenly although the nest has been there for months, and why an early start pays off.
Why not just use a wasp trap?
A trap with a sweet lure does catch wasps, but it also draws them towards where you are sitting, and it catches bees and hoverflies along with them. Deterrence works the other way round: it keeps the area clear instead of attracting insects to it.