Phosphoramidates are a class of chemical compounds still widely used for insect pest control; therefore, in this group, there is an underlying need to investigate novel insecticide compounds. This study evaluated the insecticidal efficacy and physiological selectivity of three novel aminoaryl-phosphoramidate compounds under controlled laboratory conditions. The biological models were larvae of the phytophagous Spodoptera frugiperda and adult workers of the predatory Polybia occidentalis. The S. frugiperda larvae used for the bioassays were reared on an artificial diet, while P. occidentalis adults were collected from field colonies. The acute larvicidal efficacy of the novel phosphoramidate compounds against S. frugiperda larvae was lower than that of the control treatment (a commercial product of the same chemical class); however, these same compounds exhibited significant acute toxicity to workers of P. occidentalis. Following topical application of phosphoramidate compounds, insects were provided an ad libitum feeding diet, and toxicity associated with potential delayed neurotoxic effects was assessed under these conditions. The LD50 (lethal dose killing 50% of the tested population) of the three aminoaryl-phosphoramidate compounds ranged from 28.10 to 99.94 μg mg-1 for S. frugiperda larvae and from 54.86 to 68.71 μg mg-1 for adult P. occidentalis adults. The synthesized compound exhibits more pronounced acute and chronic effects on the non-target insect (P. occidentalis) and a less pronounced rapid lethal effect on S. frugiperda compared to commercial insecticides, indicating undesirable properties. However, its notable delayed neurotoxic effect to S. frugiperda, which is understudied for compounds of this nature, could be further explored as an additional tool for pest control.
Neta et al. (Thu,) studied this question.