Background: The destructive insect pest Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) is a polyphagous species targeting many economically important plants. The extensive and arbitrary use of insecticides has resulted in the build-up of insecticide resistance and pesticide residues accumulating in food. Therefore, it is becoming evident that alternative pest management tools are needed to reduce risks to humans, the environment, and non-target organisms, and at the same time, they should be used in field application at the lowest cost. Methods: In view of this objective, the present study demonstrates the toxicity of lemongrass (Cymbopogon citratus (DC.) Stapf) essential oil (EO), against the black cutworm A. ipsilon under controlled laboratory conditions in terms of measuring the activity of peroxidase and detoxification enzymes. The chemical components of the EO were analyzed using GC–MS. Results: The results show that after 96 h post treatment, the LC15 and LC50 values were 427.67 and 2623.06 mg/L, respectively, of C. citratus EO on second-instar larvae of A. ipsilon. A slight significance in elongation of the larval duration with LC15 and LC50 value was found with control. By GC–MS analysis, the main compounds identified in the EO were α-citral and β-citral with percentages of 35.91%, and 35%, respectively. The oxidative stress indicates a significant increase in CAT and lipid peroxidase enzyme activity after 96 h post treatment at the LC15 and LC50. Conversely, the detoxification enzyme activity shows an inhibition of CarE and GST enzymes of larvae exposed to LC15 and LC50 values in response to C. citratus EO. Conclusions: The present data show that lemongrass EO has insecticidal activity against the black cutworm, A. ipsilon.

Frequent applications of synthetic insecticides might cause environmental pollution due to the high residue. In addition, increasing insecticide resistance in many insect pests requires novel pest control methods. Nanotechnology could be a promising field of modern agriculture, and is receiving considerable attention in the development of novel nano-agrochemicals, such as nanoinsectticides and nanofertilizers. This study assessed the effects of the lethal and sublethal concentrations of chlorantraniliprole, thiocyclam, and their nano-forms on the development, reproductive activity, oxidative stress enzyme activity, and DNA changes in the black cutworm, Agrotis ipsilon, at the molecular level. The results revealed that A. ipsilon larvae were more susceptible to the nano-forms than the regular forms of both nano chlorine and sulfur within the chlorantraniliprole and thiocyclam insecticides, respectively, with higher toxicities than the regular forms (ca. 3.86, and ca.2.06-fold, respectively). Significant differences in biological parameters, including developmental time and reproductive activity (fecundity and hatchability percent) were also observed. Correspondingly, increases in oxidative stress enzyme activities were observed, as were mutagenic effects on the genomic DNA of A. ipsilon after application of the LC50 of the nano-forms of both insecticides compared to the control. These promising results could represent a crucial step toward developing efficient nanoinsecticides for sustainable control of A. ipsilon.

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High-frequency doses of chemical pesticides cause environmental pollution with high pesticide residues. In addition, increasing insecticide resistance in many insect pests requires novel pest control methods. Nanotechnology could be a promising field of modern agriculture, and is receiving considerable attention in the development of novel nano-agrochemicals, such as nanoinsectticides and nanofertilizers. This study assessed the effects of the lethal and sublethal concentrations of chlorantraniliprole, thiocyclam, and their nano-forms on the development, reproductive activity, oxidative stress enzyme activity, and DNA changes at the molecular level of the polyphagous species of black cutworm Agrotis ipsilon. The results revealed that A. ipsilon larvae were more susceptible to the nano-formsthan the regular forms of both nano chlorine and sulfur within the chlorantraniliprole and thiocyclam insecticides, respectively, with higher toxicities than the regular forms (ca. 3.86, and ca.2.06-fold, respectively). Significant differences in biological parameters, including developmental time and reproductive activity (fecundity and hatchability percent) were also observed. Correspondingly, increases in oxidative stress enzyme activities were observed, as were mutagenic effects on the genomic DNA of A. ipsilon after application of the LC50 of the nano-forms of both insecticides compared to the control. The positive results obtained here have led us to apply these nano-forms indifferent insect models in additional studies.