Wasp Nest Killer Powders

The powder is applied at the nest entrance. Wasps returning to the nest carry it inside on their bodies, where it spreads through the colony. That is why treatment is not immediate - it works over the following days as traffic distributes it.

Check before you treat. Wasps are bright yellow and black, smooth and narrow-waisted, and build a papery grey nest from chewed wood. Honey bees are smaller, hairier and browner; bumblebees are large and furry, and often nest in the ground or in old bird boxes in small numbers. Neither should be killed, and a beekeeper will usually collect a honey bee swarm free of charge. Our guide to getting rid of wasps yourself covers how to tell them apart.

Report it rather than treating it. The Asian, or yellow-legged, hornet is an invasive species: look for a mostly dark, almost black body with a single yellow-orange band near the tail, yellow-tipped legs and an orange face. Do not approach the nest and do not apply powder to it. Photograph it from a safe distance if you can, report it through the Asian Hornet Watch app or the online reporting form, and leave it for the authorities.

Yes, when used exactly as directed. Cover up fully in light-coloured clothing - dark colours and quick movements provoke wasps - with long sleeves, trousers tucked in, gloves and eye protection. Apply at dusk or first light when most of the colony is inside and less active. Keep children and pets indoors during treatment and until the area is quiet, and plan a clear route away from the nest before you start. Never stand directly underneath the nest.

An extension applicator lets you treat entrances above head height that are still visible from the ground. Beyond that, no - a nest you would need a ladder for, or one inside a wall or roof void where you cannot see the whole entrance, is a professional job. A sting reaction while you are balancing on a ladder is how people fall and get badly hurt. So is any nest beside a doorway, path or play area where disturbed wasps have nowhere to go but at people, and any nest at all if someone in the household has a sting allergy.

Expect several days. Foragers that were away when you treated keep returning to the entrance, so continuing traffic in the first few days is normal rather than a sign of failure. What matters is whether activity falls day on day.

Two likely causes. Either the powder is not where returning wasps have to walk through it - it needs to be at the entrance itself, not near it - or the visible hole is a gap in the building leading to a nest set well back inside a cavity, so the powder never reached the colony. Re-treating a cavity nest rarely works, and that is the point to call a professional.

No. Sealing the entrance traps workers inside and pushes them to chew a new way out, often into the building rather than back outdoors. The wasps also have to walk through the powder for it to work at all. Leave it open until all activity has stopped, then seal the gap so it cannot be used again.

Once activity has fully stopped, seal the gap they were using and check the rest of the roofline, soffits, sheds and bird boxes for others. Wasps do not reuse an old nest, but a site that suited one queen will suit another, so closing the access is the fix rather than removing the nest. Inspect again the following spring, while any new nest is still small.