Methomyl is a carbamate insecticide introduced in 1966. It is highly toxic to humans, livestock, pets, and wildlife.[3]The EU imposed a pesticide residue limit of 0,01 mg/kg for all fruit and vegetables.[4]
Methomyl is a common active ingredient in commercial fly bait, for which the label instructions in the United States 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.[5][6]
Methomyl is a broad-spectrum insecticide that is used to kill insect pests.[7] Methomyl is registered for commercial/professional use under certain conditions on sites including field, vegetable, and orchard crops; turf (sod farms only); livestock quarters; commercial premises; and refuse containers. Products containing 1% Methomyl are available to the general public for retail sale, but more potent formulations are classified as restricted-use pesticides: not registered for homeowner or non-professional application.[7] However, Heliothis virescens developed a resistance to methomyl within 5 years.[8] Other species like Helicoverpa assulta also developed resistance after exposure.[9]
In acute toxicity testing, methomyl is placed in EPA Toxicity Category I (the highest toxicity category out of four) via the oral route and in eye irritation studies.[7] It is in lower Toxicity Categories for inhalation (Category II), acute dermal effects (Category III), and acute skin irritation (Category IV). Methomyl is not likely to be a carcinogen (EPA carcinogen Category E).[7]
Methomyl has low persistence in the soil environment, with a reported half-life of approximately 14 days.[10] Because of its high solubility in water, and low affinity for soil binding methomyl may have potential for groundwater contamination.[7][11] The estimated aqueous half-life for the insecticide is 6 days in surface water and over 25 weeks in groundwater.[11]
First prepare thioester:
Second prepare oxime from thioester:
Third prepare product from methyl isocyanate and the finished oxime:
Common names for methomyl include metomil and mesomile. Trade names include Acinate, Agrinate, DuPont 1179, Flytek, Kipsin, Lannate, Lanox, Memilene, Methavin, Methomex, Nudrin, NuBait, Pillarmate and SD 14999 [11]