Toxicity and sublethal effects of chlorantraniliprole and indoxacarb on Spodoptera littoralis (Lepidoptera: Noctuidae)

Abstract

Chlorantraniliprole and indoxacarb insecticides exhibit good efficiency for control lepidopteran pests. The current study is a comprehensive analysis of the effect of lethal and sublethal concentrations of these insecticides on Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) by using the leaf dipping technique. The LC 50 values ranged from 0.06 to 1.07 mg/L, and 0.005 to 0.81 mg/L for chlorantraniliprole and indoxacarb, respectively. Our results showed that the treatment of the 2nd instar larvae with LC 50 concentrations of these insecticides significantly increased the length of larval and pupal duration as well as pupal weight in most cases. While, no significant differences have been found in the percentage of hatchability except for LC 50 equivalent of indoxacarb. Female behavior regarding calling activity decreased by 50-60% following exposure to the LC 50 concentration of both insecticides. Gas chromatography analysis results showed that both insecticides lowered pheromone titer except at chlorantraniliprole LC 50 equivalent for (Z,E)-9,12-tetradecadien-l-ol acetate, and indoxacarb LC 10 equivalent for (Z)-9-tetradecenyl acetate. Additionally, the activity of mixed-function oxidases and glutathione S-transferase were elevated relative to control. The carboxylesterase activity significantly increased when assayed with both chlorantraniliprole concentrations and indoxacarb LC 10 equivalent. These results indicate that chlorantraniliprole and indoxacarb could be effective for S. littoralis control.

Molecular and Functional Characterization of Pyrokinin-Like Peptides in the Western Tarnished Plant Bug Lygus hesperus (Hemiptera: Miridae)

“…For S. littoralis samples, the same GC-MS unit was used, but with an Agilent J&W VF WAXms (60 m × 0.25 mm × 0.25 μm) polar capillary column. Running conditions were as described by Moustafa et al [81]. Authentic standards were initially injected in scan mode.…”

Nano-Insecticides Against the Black Cutworm Agrotis ipsilon (Lepidoptera: Noctuidae): Toxicity, Development, Enzyme activity, and DNA Mutagenicity

“…In contrast, A. ipsilon larvae were more susceptible to chlorantraniliprole and its nano-form than thiocyclam (Table 1). Other lepidopteran pests, including Helicoverpa armigera, Spodoptera exigua, and Spodoptera littoralis [31,60,61] are also susceptible to this insecticide. The chlorantraniliprole showed harmful activity toward the third instar larvae of A. ipsilon [62], whereas its LC 50 was 0.187 μg/g 72 h post treatment.…”

“…Several studies have also shown that low concentrations of insecticides may affect the reproductive activity of insects (e.g., Helicoverpa assulta, Mamestra brassica, and S. littoralis [31,68,33].…”

“…Sublethal effects of insecticides could be considered common toxicological phenomena and represent a secondary effect of insecticide application [62,64]. This phenomenon may occur in insects due to exposure to degraded insecticide after itsinitial application on crops [31]. When second instar larvae of A. ipsilon are exposed to sublethal concentrations of chlorantraniliprole, thiocyclam, and their nano-forms, the developmental rates of the larvae and pupae were substantially extended (Table 2) in the original form of both insecticides compared to their nano-forms.…”

“…The toxicity of chlorantraniliprole, thiocyclam, and their nano-forms on the second instar larvae were assessed using the leaf dipping technique [31], with some modifications. Briefly, six different concentrations were prepared for each, and water was used to control the larvae.…”