Monitoring Resistance and Biochemical Studies of Three Egyptian Field Strains of Spodoptera littoralis (Lepidoptera: Noctuidae) to Six Insecticides

Abstract

Background: Spodoptera littoralis (Boisd.) is a prominent agricultural insect pest that has developed resistance to a variety of insecticide classes. In this study, the resistance of three field strains of S. littoralis, collected over three consecutive seasons (2018 to 2020) from three Egyptian Governorates (El-Fayoum, Behera and Kafr El-Shiekh), to six insecticides was monitored. Methods: Laboratory bioassays were carried out using the leaf-dipping method to examine the susceptibility of the laboratory and field strains to the tested insecticides. Activities of detoxification enzymes were determined in an attempt to identify resistance mechanisms. Results: The results showed that LC50 values of the field strains ranged from 0.0089 to 132.24 mg/L, and the corresponding resistance ratio (RR) ranged from 0.17 to 4.13-fold compared with the susceptible strain. Notably, low resistance developed to spinosad in all field strains, and very low resistance developed to alpha-cypermethrin and chlorpyrifos. On the other hand, no resistance developed to methomyl, hexaflumeron or Bacillus thuringiensis. The determination of detoxification enzymes, including carboxylesterases (α- and β-esterase), mixed function oxidase (MFO) and glutathione-S-transferase (GST), or the target site of acetylcholinesterase (AChE), revealed that the three field strains had significantly different activity levels compared with the susceptible strain. Conclusion: Our findings, along with other tactics, are expected to help with the resistance management of S. littoralis in Egypt.

Towards Sustainable Pest Management: Toxicity, Biochemical Effects, and Molecular Docking Analysis of Ocimum basilicum (Lamiaceae) Essential Oil on Agrotis ipsilon and Spodoptera littoralis (Lepidoptera: Noctuidae)

“…Detoxification enzymes are key players in insecticide metabolism in insects (Fouad et al 2022 ; You et al 2022 ; Aioub et al 2023 ; Moustafa et al 2023c ; Prasannakumar et al 2023 ). Insect resistance is usually accompanied with enhanced activity of these enzymes (David et al 2013 ).…”

The Synergistic Effect of Lemongrass Essential Oil and Flometoquin, Flonicamid, and Sulfoxaflor on Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae): Insights into Toxicity, Biochemical Impact, and Molecular Docking

“…Crop production has been accompanied by the widespread use of various pesticides for maintaining crop productivity while minimizing pest damage [41]. However, the frequent increase in pesticide applications has not resulted in large decreases in pest populations; rather, it has contributed to the development of pest resistance to routinely used pesticides [42,43]. When managing a particular pest, the fundamental purpose of pest management combinations is to minimize the concentration of each component while maintaining a high level of efficacy.…”

Lethal and Sublethal Effects of Cyantraniliprole on the Biology and Metabolic Enzyme Activities of Two Lepidopteran Pests, Spodoptera littoralis and Agrotis ipsilon, and A Generalist Predator, Chrysoperla carnea (Neuroptera: Chrysopidae)

“…However, there are many insecticide application options to choose from, and each differs in its effectiveness, costs, and risks to the environment and human health [ 58 , 59 , 60 , 61 ]. Therefore, it is necessary to make well-founded decisions that consider how pesticides impact all aspects of pest management including natural enemies, crop production, economic outcomes, and resistance [ 16 , 62 ]. In this study, we assessed the effects of cyantraniliprole as a novel insecticide on the potential management of two destructive lepidopteran pests, S. littoralis and A. ipsilon.…”

“…These enzymes can remove toxins and detoxify insecticides [ 82 ]. Therefore, several studies elucidated the role of these enzymes on lepidopteran insect pests [ 17 , 22 , 39 , 62 ], which suggests the possibility of discovering new insecticidals that act by interfering with metabolic-mediated enzymes in insects [ 83 ].…”