Methiocarb-d3 is intended for use as an internal standard for the quantification of methiocarb by GC- or LC-MS. Methiocarb is a carbamate pesticide with insecticidal, molluscicidal, acaricidal, and bird repellant properties. It inhibits acetylcholinesterase (AChE) activity and is toxic to the western flower thrip (F. occidentalis; IC50 = 2.1 μM; LC50 = 3.26 ppm). Methiocarb is also toxic to the land snail M. obstructa (LD50 = 27.4 μg/snail) and the citrus mite A. pelekassi, inducing 94% mortality when used at a concentration of 0.5 ppm. It reduces the seasonal percentages of cotton bolls infested with pink bollworm (P. gossypiella) to 4%, compared with 65% infestation in untreated controls, when applied to cotton fields at a concentration of 1.86 lb/acre. Methiocarb reduces damage to grapes by song birds when applied to vineyards at a concentration of 2.5 lbs AI per 100 gal water per acre. It is an estrogen receptor α (ERα) and ERβ agonist (EC20s = 19.87 and 20.24 μM, respectively) and an androgen receptor antagonist (IC50 = 13.89 μM) in cell-based reporter assays. It is toxic to juvenile rainbow trout (O. mykiss) and guppies (P. reticulata) with LC50 values of 0.8 and 1.48 mg/L, respectively, at 48 hours of exposure. Formulations containing methiocarb have been used in the agricultural control of pests.
