Triazophos-d5 (Hostathion 40EC-d5) is the deuterium labeled Triazophos(HY-B0828)[1]. Triazophos, a non-systemic insecticide and acaricide that acts as an acetylcholinesterase (AChE) inhibitor, covalently and irreversibly binds to the acetylcholine binding site, thus blocking the hydrolysis of acetylcholine and leading to hyperexcitability, it is effective against a variety of soil insects and mites, including aphids, thrips, midges, beetles, Lepidoptera larvae, cutworms, and spider mites in crops such as ornamentals, cotton, rice, maize, soybeans, oil palms, olives, and coffee.