Spiders belong to an ancient group of animals called the Arachnids. Arachnids include scorpions, ticks and mites, harvestmen and false scorpions. Worldwide there are about 36,000 spiders.
Almost all spiders possess venom for the purpose of subduing their prey, normally insects. This makes spiders one of the most beneficial of invertebrate groups. Spider venom is occasionally used against humans. This usually happens when the spider is trying to defend itself. While many spiders are not able to penetrate human skin with their fangs, those that can, occasionally inflict painful and in rare cases, dangerous bites.
To successfully treat spiders a broad spectrum external spray is used and where possible vents, weep holes and cavity walls are dusted along with the roof voids and any harbouring areas. Different spider species harbour in different places depending on their web structures.