What kills hornets instantly?

What kills hornets instantly includes physical methods and certain chemicals that cause rapid death on contact, though humane deterrence and professional removal are recommended for nests due to ecological benefits and sting risk. Fastest way to kill hornet instantly is physical crushing with fly swatter, shoe, or rolled newspaper that crushes hornet immediately, though this can provoke other hornets if near nest as alarm pheromones may be released that attract more hornets to defend colony. Vacuuming with strong suction removes hornet instantly and contains it, though hornet may not die immediately inside vacuum but will be trapped and eventually die, and you should dispose vacuum bag outside. Chemical methods that kill instantly on contact include insecticide sprays labeled for hornets containing pyrethrins, pyrethroids, or hornet freeze sprays that kill on contact within seconds when sprayed directly, and hornet sprays that shoot up to 20 feet can kill from distance which is safer for nests. Soapy water spray kills hornets quickly by clogging spiracles and causing suffocation, as soap breaks surface tension and blocks breathing, killing within minutes. Boiling water kills instantly when poured directly but is dangerous to use. For nests, professional pest control uses insecticidal dusts that kill colony quickly. However, killing individual hornets is not always necessary, as hornets are beneficial predators that control pest insects, and indiscriminate killing can cause more aggression.