Aldicarb is a carbamate insecticide which is the active substance in the pesticide Temik. It is effective against thrips, aphids, spider mites, lygus, fleahoppers, and leafminers, but is primarily used as a nematicide.^[1] Aldicarb is a cholinesterase inhibitor which prevents the breakdown of acetylcholine in the synapse. In case of severe poisoning, the victim dies of respiratory failure.

Aldicarb is effective where resistance to organophosphate insecticides has developed, and is extremely important in potato production, where it is used for the control of soil-borne nematodes and some foliar pests. Its weakness is its high level of solubility, which restricts its use in certain areas where the water table is close to the surface.

Regulatory status

Aldicarb is approved by the USEPA for use by professional pesticide applicators on a variety of crops, including cotton, beans, and others. It is not approved for household use.^[2]

"Tres Pasitos", a mouse, rat, and roach killer that contains high concentrations of aldicarb, has been illegally imported into the United States from Mexico and other Latin American countries. The product is highly toxic to animals and people, and according to the EPA "should never be used in [the] home."^[3]

History

Aldicarb is manufactured by Bayer CropScience, but was formerly owned and produced by Union Carbide. Union Carbide's agricultural chemicals division was sold to Rh ne-Poulenc. Later, Aventis Cropscience was formed from Hoechst AG and Rhone-Poulenc Agrochemical, which lasted until Bayer acquired it in 2002.

In 1985, nearly 1000 people in the western United States and Canada were poisoned by residue of aldicarb in watermelons. Their symptoms included nausea, vomiting, blurred vision and muscle weakness. Although no one died, some of the victims were seriously ill, and two women later gave birth to stillborn babies. Later epidemiologic surveys of women who were pregnant at the time of the poisoning event failed to establish a causal relationship between the stillbirths and pesticide exposure.

In November 2009, corn treated with Temik was placed in and around peanut fields in Eastland County, Texas, near the town of Cisco. The corn was eaten by feral hogs, deer, and other animals, prompting the Texas Parks and Wildlife Department to issue a hunting ban.^[4]

Toxicity in mammals

Aldicarb is a fast-acting cholinesterase inhibitor, causing rapid accumulation of acetylcholine at the synaptic cleft. It is widely used to study cholinergic neurotransmission in simple systems such as the nematode C. elegans.

Exposure to high amounts of aldicarb can cause weakness, blurred vision, headache, nausea, tearing, sweating, and tremors in humans. Very high doses can be fatal to humans because it can paralyze the respiratory system.^[3]

It has an of 0.5-1.5 mg/kg when in liquid form and an of 7 mg/kg when in solid form. Because of its toxicity, its use is highly restricted in the EU/UK with maximum residue limits for apples and oranges being 0.02 mg/kg and this amount is only allowed because this is the limit of detection.

References

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