The most common household spider that is found high in the corners of rooms is the harvestman, fondly nicknamed the ‘daddy longlegs’. Daddy longlegs are webbing spiders and are well-known for being ‘useful’ spiders. This is because they are known to fend off venomous redback spiders, which are also very common in Australian homes. Despite the web nests left behind, daddy longlegs are not a bad spider to tolerate inside your home, granted you are not arachnophobic.
The treatment for a spider infestation will usually involve the use of chemicals that come into direct contact with the spiders. Spiders do not have veins in their legs, and thus will not absorb the chemical by walking through it. They do not clean their feet like a cockroach, meaning that they will not ingest the chemical either. The only way to overwhelm a spider with a chemical is to coat its environment in the substance so that it stays in contact with it for a prolonged period. Some chemicals will also crystallise in spider webs, where they can come into contact with the spider’s body and begin working.
In general, for webbing spiders, three months is the average warranty. Spider treatments will need to be repeated at this time for the most effective results.