Some chemicals that kill termites are arsenic trioxide, bifenthin, permethrin, fipronil, and imidacloprid. Arsenic trioxide is better known as arsenic dust and is a deadly poison that can be applied in powder form to wooden surfaces. Bifenthin and permethrin are liquid repellent chemicals that are commonly used in the pest control industry. Firpronil and imidacloprid are synthetic non-repellent chemicals that are common active ingredients in products that kill termites.
Arsenic trioxide is a lethal position that kills termites on contact. It is most effective when applied directly to wooden surfaces but can also be used to poison a bait box in which termites are attracted through wood or scent and then killed by the poison. Arsenic trioxide is a highly dangerous poison and must be handled very carefully. In some cases, a professional should apply the chemical.
Fipronil is the active chemical in the product Termidor. It kills termites by disrupting their central nervous system and has the potential to be fatal on contact in large doses. Fipronil is dissolved in water and placed underground beneath homes in order to create a preventive barrier against termite infestation.
Imidacloprid is a synthetic chemical derived from nicotine that is the active ingredient in the product Premis, which is used to kill termites underground. Imidacloprid infects termites through contact or digestion. Unlike fipronil, imidacloprid is a slow-acting chemical, allowing infected termites to spread the poison to other members of their colony. If imidacloprid reaches a colony's queen, the termites in the colony will most likely die out.
Bifenthin and permethrin are highly toxic and repellent to subterranean termites and are often used in pre-construction treatments. Bifenthin is the active ingredient in Talstar Professional and Bifen, and permethrin is the active ingredient in Dragnet FT and Prelude.