Flubendiamide symptoms

Figure 2 shows the early phase of research for flubendiamide. In 1989, Dr. T. Tsuda, at Osaka Prefecture University in Japan, reported that some pyrazinedicarbox-amide derivatives showed moderate herbicidal activity [5]. From 1990, the research for herbicide discovery was conducted at NNC Research Center. In the course of this research, a lead compound for an insecticide was discovered in 1993 from the class of benzenedicarboxamides as shown in Figure 2. This compound provided insecticidal activity on lepidoptera at the relatively high dose of 50-500 mg a.i./L. Moreover, it did not show activity against other species such as Hemiptera or Aca-rina. Although the level of activity was not satisfactory, this compound attracted the attention of researchers for both the novelty of its chemical structure and the characteristic insecticidal symptoms such as gradual contractions of the insect body. We therefore started the study for further optimization of this lead compound.

A novel mode of action was first suggested by the characteristic symptoms induced by flubendiamide, such as gradual contractions of insect body, thickening and shortening without convulsions (Fig. 31.2). Though the symptoms were obviously different from those of existing insecticides, similar symptoms were also seen in insects treated with the plant alkaloid ryanodine, a modulator of a... 

The speed of appearance of symptoms on larvae treated with flubendiamide indicates its fast acting activity (Fig. 31.6). Symptoms caused by flubendiamide... 

From its unique symptom and new mode of action flubendiamide would be expected not to show cross-resistance with conventional insecticides. Thus, when the activity of flubendiamide against larvae of P. xylosteUa resistant to synthetic pyrethroids, benzoylphenylureas, organophosphates and carbamates was evaluated, flubendiamide provided the same EC50 values against both the resistant and the susceptible strains [8, 13], The absence of cross-resistance between flubendiamide and conventional insecticides is probably because of its new mode of action. This indicates that flubendiamide will fit well into insecticide resistance management (IRM) programs. 

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