How can I stop wasps nesting in my French second home?

Reader question: In spring I found a wasp nest in the garage of my second home. What can I do to prevent them from returning this winter? 

Wasps usually seek sheltered spots close to water, dry wood and food to build their nests. This makes many French holiday homes ideal places, particularly in attics.

In spring and early summer, wasps hunt insects and caterpillars to feed their young. Later in the season, they are also attracted to sugary foods and ripe fruit.

The nests are usually grey, made from a papier-mâché-like material produced by chewing wood and mixing it with saliva. They consist of clusters of cells.

Their size is often dictated by the space available. Large nests can sometimes be found filling the cavities in concrete building blocks, for example, while smaller ones are often discovered under roof tiles.

Queen wasps, which have hibernated over winter in cracks in wood or stone walls, start building nests in spring. They produce the first workers, which then help to extend the nest.

Check for nests early in the season

Since you are unlikely to be able to monitor the property yourself, it is worth asking a neighbour or the person who mows the lawn to look specifically for early-stage nests each spring.

Spotting a nest early can make dealing with it easier and safer than tackling a mature one later in the summer. Do not attempt to remove a nest yourself if it is active or difficult to reach: contact a pest-control professional.

Seal potential entry points

Before leaving the house, seal gaps that might allow wasps to enter roof spaces or other sheltered areas. Fit fine mesh over air vents and chimney openings, and repair damaged roof tiles or render. Make sure ventilation is not obstructed and that any mesh is suitable for the opening.

Keep shutters closed when the house is empty. This can remove an easy entry route and a sheltered space behind them, where wasps sometimes build nests.

Try traps and other deterrents

You can make traps by cutting a plastic water bottle about a third of the way down, turning the top upside down and placing it back inside the bottom to form a funnel. Fix it in place with staples or tape.

A suggested bait is a mixture of fruit syrup and beer or wine, with a drop of washing-up liquid. Hang traps away from areas used by people and pets, and arrange for someone to check and refresh them regularly.

However, traps are not a reliable way to prevent nests being built, and they can also catch other insects. Avoid placing them where they might attract wasps close to the house.

Other suggestions include soaking cloths with essential oils such as citronella or lavender and leaving them near potential nesting sites. However, there is little reliable evidence that these will prevent wasps from settling.

Wasps are sometimes said to avoid building nests near existing ones, so placing old or imitation wasp nests in strategic locations is another suggestion. You can buy artificial nests online, but their effectiveness is not well established.

Reduce food sources around the property

Cover bins tightly and do not leave food waste, ripe fruit or open drinks outside. Keep compost bins well sealed.

These measures are particularly useful later in the summer, when wasps are attracted to sugary foods, although they are less relevant to preventing nests from being established in spring.