Using Wasp Spray Correctly — and Its Limits
By Wespenprofis.ch · Reviewed by:Fachbewilligung Schädlingsbekämpfung VFB-S · Updated: 3 July 2026
At a glance
For professionals, biocide-based wasp spray is the last resort when there is an acute danger or when a nest cannot be reached any other way. The aerosol is sprayed directly into the entrance hole from a distance of around 2 metres, sometimes supported by powder or diatomaceous earth. For non-specialists, over-the-counter sprays carry considerable risks, because dosage, distance and follow-up checks decide whether the treatment is successful and safe.
Biocides as a last resort
Of the four professional methods of wasp nest removal, the use of biocides is the least preferred. Licensed professionals only fall back on it when freezing treatment, mechanical removal or relocation are not an option — for example when people are in acute danger, or when nests sit in completely inaccessible cavities that cannot be reached any other way.
How a professional application works
The aerosol is sprayed directly into the entrance hole of the nest from a safety distance of around 2 metres. The active substance clings to the wasps, which carry it into the interior of the nest as they fly in and out, so that even distant sections and the brood are reached. Where nests sit in cavities that are hard to access, deep inside a crack in a wall for example, powder or diatomaceous earth is used in addition: the fine dust settles on the wasps’ bodies as they pass through the entrance and stays effective over a longer period.
Why this is risky for non-specialists
At first glance, over-the-counter sprays look easy to use, but in practice distance, dosage, wind direction and hitting the right opening decide whether the treatment is successful and safe. If too little active substance is applied, or if only the surface of the nest is hit, the colony reacts aggressively without the danger being removed. In addition, many effective products are not approved for private use at all, or require protective equipment that non-specialists usually do not have.
After the treatment
A dead nest that has been treated with biocides does not need any further treatment. Professionals do, however, check that there really is no activity left before the nest is removed or left in place. Why home remedies such as smoking out a nest or using water are unsuitable alternatives is explained in the guide removing a wasp nest yourself. For a professional assessment and the right choice of method, get in touch via wasp nest removal; prices are listed under our prices.
Frequently asked questions
Why are biocides only a last resort?
Freezing treatment, mechanical removal and relocation are gentler on the environment and on non-target organisms. Biocides are only used when there is an acute danger or when the nest cannot be reached any other way.
How is wasp spray applied properly?
The aerosol is sprayed directly into the entrance hole from a distance of around 2 metres, so that the wasps themselves carry the active substance into the interior of the nest. In cavities that are hard to reach, powder or diatomaceous earth is used in addition.
Why should non-specialists avoid over-the-counter sprays?
The wrong dosage, too short a distance or an incomplete treatment often mean that the colony is merely provoked rather than eliminated — with a correspondingly high risk of stings.