The insecticidal potencies of dinotefuran and analogues against the adult male American cockroach, Periplaneta americana (L) were measured by injection with or without metabolic inhibitors. The potency of dinotefuran was close to those of clothianidin and imidacloprid under the conditions used. The nerve-excitatory and nerve-blocking activities were measured with central nerve cords of P americana. The nerve-excitatory activity of dinotefuran was lower than that of imidacloprid, but was comparable with that of clothianidin. The nerve-blocking activity of dinotefuran was comparable with that of imidacloprid and slightly higher than that of clothianidin. Quantitative analyses showed that variations in the insecticidal activity were better correlated with variations in the nerve-blocking activity than with those in the nerve-excitatory activity when the contribution of the hydrophobic factor was allowed for.

An imidacloprid-related nitromethylene compound and its alkyl congeners at the imidazolidine NH site were prepared and their insecticidal and nerve-excitatory and -blocking activities were measured. In the insecticidal test with the male adult American cockroach by the injection method, metabolic inhibitors, more or less, increased the activity of tested compounds. The NH mother compound was the most active among the nitromethylene compounds and was as active as imidacloprid under the synergistic conditions. The N-alkyl congeners were less active than the NH compound under the conditions. In both of the nerve excitatory and blocking activities measured with a central nerve cord of the American cockroach, the NH compound was the most active among the nitromethylene series compounds and was less active than imidacloprid.A good correlation was not observed between the nerve activities. Quantitative analyses showed that the insecticidal activity measured with the metabolic inhibitors was better correlated with the nerve-blocking activity than with the nerve-excitatory activity. When factors of transport of the compounds within the insect body and/or interaction with target sites were considered separately by use of the hydrophobicity parameter, the correlation with the nerve-blocking activity was significantly improved.

No abstract

The insecticidal activity of dinotefuran and 23 related compounds against the housefly, Musca domestica (L) was measured by injection with metabolic inhibitors. Dinotefuran was less active than imidacloprid and clothianidin by a factor of 10 in molar concentrations. Their binding activities to the fly-head membrane preparation were measured by using [125I]alpha-bungarotoxin ([125I]alpha-BGTX) and [3H]imidacloprid ([3H]IMI) as radioligands. The activity of some selected compounds measured with [3H]IMI was 10(4)-fold higher than that measured with [125I]alpha-BGTX. With [3H]IMI as a radioligand, dinotefuran was 13-fold less active than imidacloprid. The inhibitory effect of dinotefuran on the binding of [3H]IMI to the membrane preparation was in a competitive manner. Quantitative analysis of the insecticidal activity of the test compounds with the binding activity measured with [3H]IMI showed that the higher the binding activity, the higher was the insecticidal activity.

No abstract