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Simple Summary: The fall armyworm, Spodoptera frugiperda, represents a major threat to cereal crops. Therefore, this study aimed to detect the resistance of the second-instar larvae of S. frugiperda in two Egyptian field strains to eight insecticides. The results showed that emamectin benzoate, had the highest toxicity against the susceptible and the two field populations of S. frugiperda larvae followed by spinosad > lufenuron > diflubenzuron > cypermethrin > profenfos > methoxyfenozide > Bacillus thuringiensis. Additionally, resistance to cypermethrin followed by spinosad and lufenuron was observed in Fayoum field population. Thus, the combined use of synergists with cypermethrin, spinosad, and lufenuron showed synergistic effects against S. frugiperda larvae. This study underscores the need for pest management strategies based on regional resistance profiles and biochemical characteristics. Spodoptera frugiperda (J.E. Smith) (Noctuidae: Lepidoptera) is a notable insect pest that invades major cereal crops, causing significant damage and loss. Resistances of 2nd instar larvae of two Egyptian field populations of S. frugiperda, collected from the Fayoum and Giza governments, were measured against eight insecticides, including traditional insecticides (profenofos and cypermethrin), bio-insecticides (emamectin benzoate, spinosad, and Bacillus thuringiensis), and insect growth regulators (IGRs) (lufenuron, diflubenzuron, and methoxyfenozide). In addition, the synergistic effects of three synergists (Piperonyl butoxide (PBO), diethyl maleate (DEM), and triphenyl phosphate (TPP) were assessed, and the activities of detoxification enzymes (acetylcholine esterase (AChE), cytochrome P-450 (CYP-450), carboxylesterase (CarE), and glutathione-s-transferase (GST) were also determined. Resistance surveillance revealed that the Fayoum field population showed moderate resistance to cypermethrin (RR = 5.75-fold), followed by spinosad (RR = 2.62-fold), and lufenuron (2.01-fold). On the other hand, the Giza population exhibited significant resistance to cypermethrin only (RR = 3.65-fold). Our results revealed that emamectin benzoate was the most effective insecticide, with an LC50 value of 0.003 mg/L for the Fayoum population and 0.001 mg/L for the Giza population, compared to the susceptible strain (0.005 mg/L). Among the biological insecticides, Bacillus thuringiensis was the least toxic insecticide of all the tested strains. Synergism assays indicated that DEM and TPP had the most synergistic effect on spinosad (SR = 8.00-fold for both), followed by PBO (SR = 5.71-fold) for the Fayoum population, compared with spinosad alone. The assay of detoxification enzymes showed that GST activity significantly (p < 0.05) increased in the two field strains compared to the susceptible strain. However, no significant changes were observed among the tested strains in CYP-450, CarE, or AChE. The findings of this study provide substantial insights into tracking and managing the development of insecticide resistance in S. frugiperda in Egypt. [ABSTRACT FROM AUTHOR]

Simple Summary: The black cutworm, Agrotis ipsilon (Hufnagel), poses a significant threat to various crops. Marjoram (Origanum majorana) and rosemary (Rosmarinus officinalis) essential oils (EOs) were investigated for their toxicity using in vitro and in silico methods. GC-MS analysis identified the main constituents, with O. majorana being more toxic than R. officinalis to A. ipsilon larvae. R. officinalis EO inhibited Na+/K+ pump activity consistently, while O. majorana showed varied effects. Both EOs influenced detoxification enzymes differently over time. Molecular docking indicated a strong binding affinity of the main EO constituents to target enzymes. These findings suggest the potential of EOs as insecticides in integrated pest management programs, particularly in organic agriculture. In this study, in vitro and in silico approaches were employed to assess the toxicity of marjoram (Origanum majorana) and rosemary (Rosmarinus officinalis) essential oils (EOs) to A. ipsilon larvae. The study determined the activities of ATPases in the larvae after treatment with the LC20 and LC70 of each EO. α-esterase and glutathione-S-transferase (GST) activities were also determined after treatment with LC10 and LC30 of each EO. Furthermore, molecular docking was employed to determine the binding affinity of terpinene-4-ol and α-pinene, the major constituents of O. majorana, and R. officinalis EOs, respectively, compared to the co-crystallized ligand of α-esterase, diethyl hydrogen phosphate (DPF). Toxicity assays revealed that O. majorana EO was more toxic than R. officinalis EO to the A. ipsilon larvae at 96 h post-treatment. However, the LC20 and LC70 of the latter significantly inhibited the activity of the Na+-K+ pump at almost all intervals. The same concentrations significantly inhibited the Mg2+/Ca2+-ATPase and Ca2+ pump at 96 h post-treatment. In contrast, O. majorana EO showed a variable effect on the Na+-K+ pump across different time intervals. On the other hand, LC10 and LC30 of both EOs showed varied effects on α-esterase and GST over time. Molecular docking revealed energy scores of −4.51 and −4.29 kcal/mol for terpinene-4-ol and α-pinene, respectively, compared to a score of −4.67 for PDF. Our study demonstrated the toxicity of the tested EOs to A. ipsilon, suggesting their potential efficacy as insecticides. [ABSTRACT FROM AUTHOR]

Simple Summary: This study discusses the effects of cyantraniliprole, a new insecticide, on two lepidopteran pests and a biological control agent. Cyantraniliprole showed higher toxicity to one pest species compared to the other, prolonged developmental stages, and increased detoxification activity in both pest species. It also had a negative but slight impact on the biological control agent at the recommended concentrations. The study suggests that cyantraniliprole can effectively control the pests while being compatible with the control agent, but further field studies are needed for validation. Cyantraniliprole is a novel anthranilic diamide insecticide registered for controlling chewing and sucking insect pests. Here, the lethal and sublethal effects of this insecticide on two destructive lepidopteran pests, Spodoptera littoralis Boisduval and Agrotis ipsilon Hufnagel, were evaluated. Because the effects of novel insecticides on beneficial and non-target arthropods must be considered, the impact of cyantraniliprole on a generalist biological control agent, Chrysoperla carnea [Stephens 1836], were also examined. Overall, our study revealed that cyantraniliprole was more toxic to A. ipsilon than to S. littoralis. Moreover, the LC15 and LC50 of the insecticide significantly prolonged the duration of the larval and pupal stages and induced enzymatic detoxification activity in both species. Treatment of the second-instar larvae of C. carnea with the recommended concentration of cyantraniliprole (0.75 mg/L) doubled the mortality rates and resulted in a slight negative effect on the biology and detoxification enzymes of C. carnea. Our results indicate that both sublethal and lethal concentrations of cyantraniliprole can successfully suppress S. littoralis and A. ipsilon populations. They also suggest that C. carnea, as a generalist predator, is compatible with cyantraniliprole under the modelled realistic field conditions. In future investigations, insights into the effects of cyantraniliprole on S. littoralis, A. ipsilon, and C. carnea under field conditions will be required to appropriately validate our results. [ABSTRACT FROM AUTHOR]

The use of essential oils as an eco-friendly tool in pest management stems from their natural origin and the presence of bioactive compounds that exhibit pesticidal properties, offering a sustainable alternative to synthetic chemical pesticides. This study explores the toxicity of Lavandula multifida (lavender) essential oil (EO), as a botanical pesticide against two widespread and destructive Noctuidae pests, Spodoptera littoralis (Boisd.) and Agrotis ipsilon (Hufnagel). GC-MS was employed to characterize 23 compounds in the EO, with 1,3,3-trimethyl-2-oxabicyclo [2.2.2] octane (eucalyptol) (39.84%), being the primary component. The leaf dipping technique was utilized to assess the toxicity of the EO to both insects. At 96 hours post-treatment, the LC50 of lavender EO to S. littoralis and A. ipsilon larvae were 2.350 and 2.991 mg · ml-1, respectively. Concerning its biological effect, both concentrations of the EO (LC15 and LC50) significantly shortened the duration of the larval (to 15.24 and 14.23 days) and pupal (to 11.19 and 10.55 days) stages of S. littoralis. Biochemical assays revealed that the LC50 of lavender EO significantly inhibited a-esterase activity in S. littoralis at 72- and 96 hours post-treatment (0.031 and 0.063 mmol · min-1 · mg-1), and A. ipsilon at 96 hours post-treatment (0.129 mmol · min-1 · mg-1 protein). Given its significant toxicological, biological, and biochemical effects on S. littoralis, it is suggested that lavender EO could be considered for use in integrated pest management strategies while ensuring its safe application to protect non-target organisms. [ABSTRACT FROM AUTHOR]

Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is a major economic pest attacking a variety of crops in Egypt and other Mediterranean countries. S. littoralis has developed resistance to both traditional and novel insecticides. The current study investigated S. littoralis resistance to indoxacarb regarding inheritance mode, realized heritability (h 2), and fitness costs. An indoxacarb-resistant strain (Indoxa-SEL) was obtained by selecting a field strain with indoxacarb. Indoxa-SEL strain outperformed the susceptible one (Indoxa-S) by 29.77-fold after 16 consecutive generations of selection. Based on the LC50 values of the progenies of reciprocal crosses F1 (R♂ × S♀) and F1ʹ (R♀ × S♂), S. littoralis resistance to indoxacarb was found to be autosomal and partially recessive. Chi-square tests for goodness-of-fit between observed and expected mortalities of self-bred F1 and resistant strain reciprocal crosses revealed that the resistance was controlled by multiple genes. The resistant strain had a relative fitness of 0.80, with significantly increased total preovipositional period of females, egg, larvae, pupae, preadult, adult, and total longevity period. The estimated realized heritability value in the Indoxa-SEL strain was 0.21. The current study will contribute to sustaining indoxacarb efficacy and designing effective resistance management programs against S. littoralis. [ABSTRACT FROM AUTHOR]

The present study investigates the insecticidal and biochemical effects of two essential oils (EOs) and two photosensitizers against cotton aphids in a laboratory setting. The EOs evaluated were clove (Syzygium aromaticum L.) and basil (Ocimum basilicum), while the photosensitizers were rose bengal and rhodamine B. The individual median lethal concentrations (LC50) revealed that clove was ~4.44 times more potent than basil, and rhodamine B was ~1.34 times more potent than rose bengal. The mortality rates increased using higher concentrations of the photosensitizers and prolonging exposure time to sunlight. The most effective combination against adult aphids was found to be a mixture of sub-lethal concentrations of clove and rhodamine B, resulting in a mortality rate of 92.31%. Conversely, the combination of basil and rose bengal exhibited the lowest efficacy with a mortality rate of 33.33%. Biochemical analyses indicate that Rhodamine B, basil, and the basil-rhodamine B mixture (mixture C) significantly reduced trehalase activity. However, the protease activity significantly increased in aphids treated with rose bengal, clove, and the clove-rose bengal mixtures (mixtures A and B). The lipase activity is notably decreased upon treatment with rhodamine B and clove. Glutathione S-transferase (GST) activity decreased in aphids treated with rose bengal and the basil-rhodamine B mixtures (mixtures C and D), suggesting that GST did not play a role in detoxifying these compounds, thereby explaining the susceptibility of A. gossypii. Overall, the combination of essential oils and photosensitizers has demonstrated a synergistic effect in controlling Aphis gossypii, offering great potential as an effective strategy for aphid management. [ABSTRACT FROM AUTHOR]

The use of biological control products enhances the reduction of harmful pressures on the environment caused by the use of conventional pesticides. Therefore, this study aims to evaluate the toxicity of eight bioinsecticides on the black cutworm Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) to understand the relationships between insecticide exposure and insect response at the individual and population levels. The bioassay results showed that emamectin benzoate had high toxicity against A. ipsilon second instar larvae with an LC50 of 0.007 (mg/L). Sublethal concentration (LC30) of emamectin benzoate, spinosyn group and Bacillus thuringiensis formulation (Dipel 2X) had significantly prolonged pupal period. In addition, emamectin benzoate significantly decreased the number of eggs laid per female (135.3 ± 6.919) compared with the control treatment. Thus, the formulation of chlorfenapyr showed a 1.26-fold reduction in hatching rate. Meanwhile, the activities of oxidative stress enzymes (catalase, superoxide dismutase, lipid peroxidase, and glutathione reductase) were significantly affected due to exposure to sublethal concentration. Changes in adipokinetic hormone (AKH) transcriptional regulation were detected via SQ-PCR via using cDNA synthesized from mRNA isolated from treated A. ipsilon larvae. The results showed a higher transcription rate of AKH in spinotram- -treated larvae with a 1.42-fold increase over untreated larvae. Our results provide useful information for integrated pest management programs for A. ipsilon by using bioinsecticides. [ABSTRACT FROM AUTHOR]

Simple Summary: The insect pest, black cutworm, Agrotis ipsilon (Lepidoptera: Noctuidae), attacks the seedling stage of many field crops in several countries around the world. To control this insect pest, in this study, lemongrass (Cymbopogon citratus) essential oil observed potential insecticidal activity against the second-instar larvae of A. ipsilon. 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. [ABSTRACT FROM AUTHOR]

Pieris rapae (Lepidoptera: Pieridae) poses a significant threat to Brassicaceae crops, leading to substantial losses annually. Repeated insecticide applications are widely used to protect crops and increase the resistance of P. rapae. Exploring the biochemical and molecular basis of insecticide tolerance in P. rapae is crucial for achieving effective insect suppuration and implementing resistance control strategies. In our research, emamectin benzoate (EBZ) resistance was developed in P. rapae strain through selective pressure over 15 generations. Moreover, the biochemical mechanisms underlying resistance to EBZ and its potential cross-resistance to other insecticides were studied. Additionally, the expression levels of cytochrome P450 (CYP450) and glutathione-s-transferase (GST) genes in P. rapae were quantitatively assessed upon exposure to EBZ using real-time PCR. Our data exhibited that the LC 50 value of susceptible strain (Sus) and EBZ resistance strain (EBZ-R) were 0.009 and 8.09 mg/L, with a resistance ratio (RR) reaching 898.8-fold. The EBZ-R stain displayed notably low cross-resistance to lambda-cyhalothrin, spinetoram, and cypermethrin. However, it demonstrated a moderate level of cross-resistance to deltamethrin. Conversely, no cross-resistance was noted to chlorantraniliprole and indoxacarb. Notably, enzyme inhibitors of detoxification enzymes revealed that piperonyl butoxide (PBO) and diethyl maleate (DEM) enhanced the EBZ toxicity to the resistant strain, indicating the potential involvement of CYP450 and GST in avermectin resistance. A remarkable enhancement in CYP450 and GST activity was observed in the EBZ-R stain. CYP450 and GST genes are upregulated in the EBZ-R stain compared to the Sus strain, which serves as a basis for comprehending the mechanism behind P. rapae resistance to EBZ. The molecular docking analysis demonstrated that EBZ has a high binding affinity with CYP6AE120 and PrGSTS1 with docking energy values of -20.19 and -22.57 kcal/mol, respectively. Our findings offer valuable insights into crafting efficient strategies to monitor and manage resistance in P. rapae populations in Egypt., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Culex pipiens (Diptera: Culicidae) is a vector of many human and animal diseases. Its control is regarded as a preventative approach that is focused on effectively managing such diseases. In this context, dose response assays of two insecticides, bendiocarb and diflubenzuron were performed with two entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae against 3rd instar C. pipiens larvae. The most effective agents, combination experiments as well as enzymatic activities of phenoloxidase (PO) and chitinase (CHI) were also assessed. The results showed that diflubenzuron was more effective at low concentrations (LC 50 : 0.001 ppm) than bendiocarb (LC 50 : 0.174 ppm), whereas M. anisopliae was more effective (LC 50 : 5.2 × 10 5 conidia/mL) than B. bassiana (LC 50 : 7.5 × 10 7 conidia/mL). Synergistic interactions were observed when diflubenzuron was applied at 2- and 4-days post- exposure to M. anisopliae, with the highest degree of synergism observed when diflubenzuron was applied 2 days post-fungal exposure (χ2 = 5.77). In contrast, additive interactions were recorded with all other insecticide-fungal combinations. PO activities significantly (p ≤ 0.05) increased during 24 h after a single diflubenzuron treatment as well as when diflubenzuron was applied prior to M. anisopliae, whereas suppressed after 24 h when M. anisopliae applied prior to diflubenzuron as well as after 48 h from single and combined treatments. CHI activity increased 24 h after both single and combined treatments, the activity remained elevated 48 h after a single diflubenzuron treatment and when diflubenzuron was applied after M. anisopliae. Histological study of the cuticle by transmission electron microscopy revealed abnormalities following single and combined treatments. Germination of the conidia and production of the mycelium that colonizes the lysing cuticle was obvious when diflubenzuron was applied 48 h after M. anisopliae exposure. Overall, these results demonstrate that M. anisopliae is compatible with diflubenzuron at lower concentrations and that combined applications can improve C. pipiens management., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

The agricultural wastes adversely affect the environment; however, they are rich in polyphenols; therefore, this study aimed to employ polyphenol-enriched waste extracts for silver nanoparticles synthesis, and study the larvicidal activity of silver nanoparticles fabricated by pomegranate and watermelon peels extracts (PPAgNPs and WPAgNPs) against all larval instars of Spodoptera littoralis . The polyphenol profile of pomegranate and watermelon peel extracts (PP and WP) and silver nanoparticles was detected by HPLC. The antioxidant activity was estimated by DPPH, and FARP assays and the antimicrobial activity was evaluated by disc assay. The Larvicidal activity of AgNPs against Egyptian leaf worm was performed by dipping technique. The obtained AgNPs were spherical with size ranged 15-85 nm and capped with proteins and polyphenols. The phenolic compounds in silver nanoparticles increased about extracts; therefore, they have the best performance in antioxidant/reducing activity, and inhibit the growth of tested bacteria and yeast. The PPAgNPs were the most effective against the first instar larvae instar (LC 50  = 68.32 µg/ml), followed by pomegranate extract with (LC 50  = 2852 µg/ml). The results indicated that obvious increase in polyphenols content in silver nanoparticles enhance their larvicidal effect and increasing mortality of 1 st larval of S. littoralis Egyptian leafworms causing additive effect and synergism. We recommend recycling phenolic enriched agricultural wastes in producing green silver nanoprticles to control cotton leafworm that causes economic loses to crops., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Author(s).)