Carbofuran (Molecule of the Month for September 2006)
Carbofuran is the most toxic of the carbamate pesticides. It is used to control insects in a wide variety of field crops, including potatoes, corn and soybeans. It is a systemic insecticide, which means that the plant absorbs it through the roots, and from here the plant distributes it throughout its organs (mainly vessels, stems and leaves; not the fruits), where insecticidal concentrations are attained. Carbofuran also has contact activity against pests. Carbofuran usage has increased in recent years because it is one of the few insecticides effective on soybean aphids, which have expanded their range since 2002 to include most soybean-growing regions of the U.S.
It has the highest acute toxicity to humans of any insecticide widely used on field crops. A quarter teaspoon ( 1 mL) can be fatal. Most carbofuran is applied by commercial applicators using closed systems with engineered controls, so that there is no exposure to the chemical through pouring or measuring. Toxic effects are due to its activity as a cholinesterase inhibitor (it is thus considered a neurotoxic pesticide).
Carbofuran is also known to be highly toxic to birds. In its granular form, a single grain will kill a bird. Birds often eat numerous grains of the pesticide, mistaking them for seeds, and then die shortly thereafter. Before it was banned, granular carbofuran was blamed for millions of bird deaths per year. The liquid version of the pesticide is less hazardous to birds since they are not as likely to ingest it directly, but it is still very hazardous.
Formal Chemical Name (IUPAC)
Update by Karl Harrison
(Molecule of the Month for September 2006 )