insecticide carbamate insecticide Derivatives of carbamic acid with insecticidal properties of general formula ROC(=O)NR(1)R(2), where ROH is an alcohol, oxime, or phenol and R(1) is hydrogen or methyl. Like organophosphate insecticides, they are cholinesterase inhibitors, but carbamate insecticides differ in action from the organophosphates in that the inhibitory effect on cholinesterase is generally brief.