灭多威亦称纳乃得，英文通用名Methomyl，是一种氨基甲酸酯类杀虫剂，原药为白色晶体粉末，商品态为可湿性粉剂、可溶性粉剂或乳油。1966年美国杜邦公司首先以“Lannate/万灵”的商品名将其推广为广谱杀虫剂。主要用于棉蚜（Aphis gossypii）、斜纹夜蛾（Spodoptera litura）等的防杀。

灭多威被美国国家环境保护局（EPA）归为第一类高毒性物质，对人体皮肤、肺、消化道、肾、脾和造血器官有不同程度的毒害作用，但在对大鼠和兔的动物实验中未发现致畸、致突变、致癌作用。

Methomyl is a carbamate insecticide introduced in 1966. It is highly toxic to humans, livestock, pets, and wildlife. The EU and UK imposed a pesticide residue limit of 0.02 mg/kg for apples and oranges.

Methomyl is a common active ingredient in commercial fly bait, for which the label instructions warn that "It is a violation of Federal Law to use this product in a manner inconsistent with its labeling." "Off-label" uses and other uses not specifically targeted at problem insects are illegal, dangerous, and ill-advised.