Relationship between Insecticidal and Nerve-Excitatory Activities of Imidacloprid and Its Alkylated Congeners at the Imidazolidine NH Site

Abstract

The insecticidal and nerve-excitatory activities of imidacloprid and its alkylated congeners on the imidazolidine NH site were measured. In the insecticidal activity against the green rice leafhopper measured in a spraying test using rice seedlings, a few compounds with C3-alkyl groups were as active as imidacloprid. In the insecticidal test against the American cockroach by the injection method, the activity values were generally increased by the use of metabolic inhibitors of oxidative degradation mechanisms. Under these conditions, all of the alkyl derivatives were less active than imidacloprid, as shown by the nerve activity measured in the excised central nerve cords of American cockroaches. The higher the nerve activity, the higher the insecticidal activity when the hydrophobic factors of the compounds were considered separately.