Before tackling the issue of getting rid of wasps, I will cover some of the background features of wasps and what good they can possibly do?
The life cycle of a wasp nest colony is indeed a cycle, involving hibernation, colony establishment, colony growth and procreation. So let us start at the ‘beginning’. A fertilised queen wasp will come out of hibernation in around early to late April. The queen will emerge from the hibernation spot, typically under the bark of a tree, or other crevice.
This solitary queen will build an initial nursery nest, about the size of a golf ball. This will be in a sheltered location such as under a lean too roof, a garden shed or under a branch in bushes. She will then lay eggs inside this nursery nest to produce the first workers. This will be typically 10 – 20 eggs initially. The subsequent larvae are cared for by the queen until their emergence as an adult wasp. These initial workers will then take over the building and expansion of the nest. The queen will then not leave the nest and will become an egg laying ‘machine’.
The future intricacies of social hierarchy within the nest will be controlled by the queen. The task of the worker wasps will be to forage for food to feed the queen and the subsequent emerging grubs. Understanding the life cycle is relevant to understanding how to get rid of wasps.
The nest will then undergo a period of rapid expansion, with the queen producing 200 – 300 eggs per day. Each worker wasp lives for around 2 – 3 weeks, so with the rate of succession of new wasps, an average nest can have around 3-5000 wasps at one time. A larger nest can have up to 20,000 wasps.
After the climax of nest expansion, around mid to late summer, the rate of nest expansion slows, and the population growth stops. The queen will then produce new queen cells and lay several queen larvae. This queen will later die or become sick. Without the role of looking after the queen wasp, colony adhesion will break down and cannibalism sets in. Foraging will become more erratic and they will become more of a nuisance around pub gardens and BBQs. More of this later. Virgin queens will leave the nest, mate, and hibernate in the same way the initial queen did the previous autumn.
Many hibernating queens will be killed over winter by spiders as they share similar crevices. One queen in a nest can produce around 1,000 queens but around only 1% can be expected to survive. Warm winters will also cause the death of many queens as they will emerge early from hibernation. Long cold winters produce the most favourable conditions for a healthy wasp season. Early emergence due to a short winter means fewer plants are flowering to providing pollen. Also fewer other small prey insects are in abundance.
Overwintering queens will usually emerge from hibernation when temperatures in the shade reach around 10 degrees centigrade.
Wasp nests are only single use and so wasps do not return to use the same nest the following year.
The nest is made from wood fibres which the worker wasps have chewed with their mouth parts and carried back to the nest. The wavy pattern of the nest surface is the result of different wood sources being used.
Nests are built in holes in the ground, crevices in walls, or are constructed as free hanging nests in bushes, or hanging from eaves and joists. 77% of Vespula vulgaris and 91% of Vespula germanica build their nests underground. This indicates how wasps in the UK actually prefer to nest in the ground and away from human structures.
What Good Can Wasps Do?
Wasps play a significant role in the cycle of nature. Without them, the ecosystem will become out of balance very rapidly. They consume significant numbers of pest insects such as mosquitoes and grubs feeding on plants. They also contribute to pollination of flowers, and play a role in converting decaying matter into useful sub straights such a food for wasp grubs.
Adult wasps can not ‘eat’. In stead they ‘drink’. Wasps feeding on fruit in the garden are actually working the fruit flesh to be able to benefit from the liquid. The grubs in the nest have mouth parts capable of eating solid foods. The worker wasps who capture insects or scavenge decaying flesh will take these back to the nest. There, the hunted items will be fed to the grubs. In return the grubs will secrete a sugar rich liquid made from the chitin of the exoskeletons of the insects fed to them in a symbiotic relationship.
It is estimated that there are as many as 1,000 wasp nests per square mile in the UK. An average colony will collect 4-5 metric tonnes of insects per annum. Therefore 4,500 metric tonnes of pest insects could be being consumed per square mile each year. This is not a typing error!
How to get rid of wasps?
A common amateur attempt is to pour petrol onto a nest and set light to it. This may eliminate a nest hanging in a bush, but it may also eliminate the bush. Lighting petrol into a nest in the ground will only scorch the surrounding grass.
Products are available in hardware shops for amateur use and are very effective for those brave enough to attempt it.
Wasp ‘pots’ are available which contain a liquid attractant in which wasps will drown once they have found their way into the pot. Home made versions can also be fashioned. However, wasp ‘pots’ capture around 10% of the visiting wasps. The other 9% will return to the nest and communicate to the other wasps the location of this new food source. They do this in a similar way that bees are known do perform a ‘dance’ to within a specific location. This leads to a net increase in wasp numbers rather than a reduction.
How It Works – Residential
In the residential setting, a wasp nest in the ground, in a garden bush, or in the loft can be treated directly. There will be the option of either applying an insecticide to the nest entrance, or injecting the nest structure with insecticide directly through the side of the nest. After treatment, the nest is likely to be no longer active after around twelve hours.
The queen will have appointed some of the more mature wasps to act as sentries at the nest entrance. Their job is to turn away wasps from other nests and also any sick individuals. Amazingly, they do this by visual recognition. When treating a nest, the worker wasps are likely to be out foraging for food to bring back to the nest. The exception to this rule if the nest has been treated before dawn or after dusk.
On returning to the nest after foraging and after nest treatment, these workers will now not encounter the sentries to allow them access to the nest as they will have been compromised. Therefore returning individuals will not enter the nest. They will then become lone ‘homeless’ wasps, to live out their life without the social cohesion of the nest.
You might be able to notice how a wasp returning to a nest will hover before entry. This wasp is awaiting nest entry ‘approval’ from guard wasps. A wasp leaving a nest will fly directly away. This is to mask the presence of the nest to unwanted predators.
When treating directly into the side of a nest, the guard wasps are more likely not to have been killed. This means the returning workers have the misfortune of being allowed access to the nest. Therefore they will contribute to walking the insecticide throughout the nest.
How It Works – Commercial
If treatment is carried out before around mid July, this can lead to increased nuisance wasp activity at visitor attractions. This is because pre mid July, the nest scavengers are focusing on hunting flesh prey to feed to the grubs rather than scavenging sugary food. Post July the grubs will have developed, and are no longer supplying the sugar rich secretions to the scavenger wasps in their symbiotic relationship. These scavenger wasps then in turn rely on sugar rich supplies such as the pub garden.
As detailed above, in the earlier stages of colony development, the scavengers are being fed sugary secretions from the grubs in return for feeding the grubs with hunted insects etc. Therefore, destroying an early nest will result in ‘homeless’ scavenger wasps. These scavengers will then have to resort to searching out a replacement sweet food source to replace what was previously coming from the grubs. This will be the drinks and ice-creams.
Pegasus Pest Control is an official stockist of WaspBane, a revolutionary Integrated Wasp Management system. This is appropriate in commercial settings such as visitor attractions where nuisance wasps are an issue.
WaspBane traps are designed to intercept scavenging wasps before they learn of a good regular sugary food source. Therefore there will be no wasps to relay information back to the nest of where the beer garden or visitor attraction is.
In summary, the ‘good’ points about wasps is their ability to feed on insects such as caterpillars and other pests of agricultural plants. They also feed on dead carrion so they play a role in the decay of matter and are also a good food source for many birds.
Pegasus Pest Control aims to be able to attend a wasp nest call out the same day or within 24 hours.
Bear in mind that when stressed or crushed, wasps emit several distress chemicals. This will alert other wasps to attack so try to resist the temptation to squash individual wasps.
If you have taken the time to read this blog, please remember the benefits wasps can bring.