Insecticidal Agents Research Articles

Design, Characterization and SAR Studies of Novel Bioactive Benzylideneacetophenone Derivatives as Insecticidal Agents against Spodoptera frugiperda (Lepidoptera: Noctuidae).

Unintentional environmental effects brought on by insecticides encourage the creation of safer substitutes. A very polyphagous migrating lepidopteran pest species in Africa called S. Frugiperda causes terrible damage. In the current paper, treatment of 4-acetylphenyl 4-methylbenzenesulfonate with different aromatic aldehydes in the presence of NaOH afforded benzylideneacetophenones. The structure of the newly prepared compounds were proved by different spectroscopic techniques such as IR, 1 H-NMR, 13 C NMR, and elemental analysis. We looked at the association between contact with S. frugiperda and stricture reaction to examine their harmful effect. Additionally, S. frugiperda was used for testing the newly created compounds for their ability to kill insects. The majority of substances have been proven to be effective and promising. It has been found that 4-[3-(4-Methylphenyl)prop-2-enoyl]phenyl-4-methyl benzenesulfonate (4) was the most active with an LC50 =3.46 mg/L of 2nd instar larvae and LC50 =9.45 mg/L of 4th instar larvae. Moreover, some of biological and histopathological aspects of the synthesized products were investigated under laboratory conditions.

Generation of anti-idiotypic antibodies mimicking Cry2Aa toxin from an immunized mouse phage display library as potential insecticidal agents against Plutella xylostella

This study tried to generate anti-idiotypic antibodies (Ab2s) which mimic Cry2Aa toxin using a phage-display antibody library (2.8 × 107 CFU/mL). The latter was constructed from a mouse immunized with F (ab’)2 fragments digested from anti-Cry2Aa polyclonal antibodies. The F (ab’)2 fragments and Plutella xylostella (P. xylostella) brush border membrane vesicles (BBMV) were utilized as targets for selection. Eight mouse phage-display single-chain variable fragments (scFvs) were isolated and identified by enzyme-linked immunoassay (ELISA), PCR and DNA sequencing after four rounds of biopanning. Among them, M3 exhibited the highest binding affinity with F (ab’)2, while M4 bound the best with the toxin binding region of cadherin of P. xylostella (PxCad-TBR). Both of these two fragments were chosen for prokaryotic expression. The expressed M3 and M4 proteins with molecular weights of 30 kDa were purified. The M4 showed a binding affinity of 29.9 ± 2.4 nM with the PxCad-TBR and resulted in 27.8 ± 4.3 % larvae mortality against P. xylostella. Computer-assisted molecular modeling and docking analysis showed that mouse scFv M4 mimicked some Cry2Aa toxin binding sites when interacting with PxCad-TBR. Therefore, anti-idiotypic antibodies generated by BBMV-based screening could be useful for the development of new bio-insecticides as an alternative to Cry2Aa toxin for pest control.

Synthesis of inventive biphenyl and azabiphenyl derivatives as potential insecticidal agents against the cotton leafworm, Spodoptera littoralis

The emergence of pest resistance of Spodoptera littoralis (order; Lepidoptera, family; Noctuidae) towards the large scale of different classes of insecticides necessitates the development of some new poly-functionalized biphenyl and azabiphenyl with highly anticipated insecticidal bioresponse. Four new biphenyl carboxamidines 4a–d and four aza-analogue picolinamidine derivatives 8a–d were designed and prepared via the treatment of their corresponding carbonitriles with lithium-bis trimethylsilylamide [LiN(TMS)2], followed by hydrolysis with hydrogen chloride. Furthermore, these compounds were elucidated by spectral data, and their toxicity and insecticidal activity were screened against Spodoptera littoralis. Whereby, toxicological and biochemical aspects of the inventively synthesized biphenyl and azabiphenyl derivatives against the cotton leafworm, Spodoptera littoralis were inspected. As regards the indomitable LC50 and LC90 values, biphenyl and aza-analogues 8d, 8a, 4b, and 8b, revealed the furthermost forceful toxic effects with LC50 values of 113.860, 146.265, 216.624, and 289.879 ppm, respectively. Whereby, their LC90 values are 1235.108, 1679.044, 2656.296, and 3381.256 ppm, respectively, and toxicity index being 22.31%, 17.36%, 11.72%, and 8.76%, respectively, comparing with the already recommended, methomyl insecticide, lannate 90% SP (LC50, 25.396 and LC90, 57.860 and toxicity index, 100%). Additionally, electrochemical parameters via DFT studies were carried out for demonstrating and elucidation of structure–activity relationship (SAR) according to highly motived compounds, descriptors, and the in vivo insecticidal activities.Graphical

A Sensitive Method for Detecting Beauveria bassiana, an Insecticidal Biocontrol Agent, Population Dynamics, and Stability in Different Substrates.

Beauveria bassiana is a well-known insecticidal biocontrol agent. Despite its broad field applications, its survival, colonization, and stability under field conditions remained unclear, mainly due to the lack of a quick and reliable detection method. In this study, we developed a quantitative real-time PCR technology to monitor the stability and population dynamics of B. bassiana in different substrates (water, soil, and on the cotton leaves surface), different spores of B. bassiana applied on Chinese cabbage leaves surface, and the lethality of Pieris rapae spraying with different spores of B. bassiana. Our results showed a decreased concentration of B. bassiana DNA in all three substrates from the 1st day till 9th day of post inoculation (dpi) period, possibly due to the death of B. bassiana. After this decrease, a quick and significant rebound of B. bassiana DNA concentration was observed, starting from the 11th dpi in all three substrates. The B. bassiana DNA concentration reached the plateau at about 13th dpi in water and 17th dpi in the soil. On cotton leaves surface, the B. bassiana DNA concentration reached the highest level at the 17th dpi followed by a small decline and then stabilized. This increase of DNA concentration suggested recovery of B. bassiana growth in all three substrates. We found that the most suitable killing effectiveness of P. rapae was the 1.0 × 107 spores/mL of B. bassiana. In summary, we have established a detection technology that allows a fast and reliable monitoring for the concentration and stability of B. bassiana under different conditions. This technology can benefit and help us in the development of proper management strategies for the application of this biocontrol agent in the field.

Green synthesis, characterization, and biochemical impacts of new bioactive isoxazoline-sulfonamides as potential insecticidal agents against the Sphodroxia maroccana Ley.

Sphodroxia maroccana Ley is a pest of cork oak crops that damages the roots of seedlings and can severely impair cork oak regeneration. Since the banning of carbosulfan and chlorpyriphos, which were widely used against the larvae of Sphodroxia maroccana because of their harmful impact on the environment, until now there has been no pesticide against these pests. Therefore, it is particularly urgent to develop highly effective insecticidal molecules with novel scaffolds. Isoxazolines are a class of insecticides that act on γ-aminobutyric acid (GABA)-gated chloride channel allosteric modulators. In this work, a green synthesis of novel 3,5-disubstituted isoxazoline-sulfonamide derivatives was achieved in water via ultrasound-assisted four-component reactions, and their insecticidal activities against fourth-instar larvae of S. maroccana were evaluated. Most of the tested compounds showed insecticidal activity compared to fluralaner as positive control and commercially available insecticide. Especially, the isoxazoline-secondary sulfonamides containing halogens (Br and Cl) on the phenyl group attached to the isoxazoline, 6g (LC50 = 0.31 mg/mL), 6j (LC50 = 0.38 mg/mL), 6k (LC50 = 0.18 mg/mL), 6L (LC50 = 0.49 mg/mL), 6m (LC50 = 0.24 mg/mL), 6q (LC50 = 0.46 mg/mL), exhibited much higher larvicidal activity than fluralaner (LC50 = 0.99 mg/mL). Novel isoxazolines containing sulfonamide moieties were designed, synthesized and confirmed by two single-crystal structures of 4e and 6q. Their bioassay results showed significant larvicidal activity with significant morphological changes in vivo. These results will lay the foundation for the further discovery and development of isoxazoline-sulfonamide derivatives as novel crop protection larvicides of cork oak. © 2023 Society of Chemical Industry.

Functionalized Pyridines: Synthesis and Toxicity Evaluation of Potential Insecticidal Agents against Aphis craccivora.

Using ultrasound technology instead of traditional methods, some pyridine derivatives were prepared by a simple procedure via a four-component reaction of different aromatic aldehydes, acetyl aryl, sodium alkoxide, and malononitrile, and additionally, all prepared compounds were monitored for insecticidal activities toward nymphs and adults of cowpea aphid. Though a lot of insecticides are discovered as a novelty on the other hand, neonicotinoid compounds are reflected as the most affected insecticides against aphids and many other pests. Thus, some of the pyridine derivatives were chemically prepared as analogues to a large group of insecticides called neonicotinoids. Under laboratory conditions, the toxicity of these components was measured toward adults and nymphs of Aphis craccivora. With respect to the LC50 values, components 1f, 1d, and 1c have the utmost insecticidal bioactivity, with values of 0.080, 0.098, and 0.127 mg/L. This work covers the way to discover novel compounds for the prospective use as insecticidal representatives.

Insecticidal activity of brown seaweed (Sargassum latifolium) extract as potential chitin synthase inhibitors: Toxicokinetic and molecular docking approaches

In this study, Sargassum latifolium (S. latifolium) n-hexane extract as a novel source for insecticidal bioactive compounds was investigated. The composition of the extract was identified by using GC-MS analysis. We performed the study on four types of insects and larvae sp (Sarcophaga bullata, Tribolium castaneum, Musca domestica, and Solenopsis invicta) which cause a deleterious impact on the crops and human health. We used scanning electron microscopy to show the destructive effects of S. latifolium extract on the exoskeleton. The treatment exhibited severe morphological changes and a high mortality rate. Also, different bioinformatic approaches were utilized to investigate the possible insecticidal mechanism of the extract. Molecular docking showed the potential of the compounds to be chitin synthase inhibitors. Besides, the toxicokinetic parameters of the most promising compounds were evaluated to assess the impact of using the extract as an insecticidal agent on human health. S. latifolium extract exhibited promising insecticidal activity and acceptable toxicokinetic properties as compared to other known pesticide groups.

Perfect Complementarity Mechanism for Aphid Control: Oligonucleotide Insecticide Macsan-11 Selectively Causes High Mortality Rate for Macrosiphoniella sanborni Gillette.

Macrosiphoniella sanborni is a widespread pest of Chrysanthemum morifolium that causes significant damage to world floriculture. Chemical insecticides and biological methods of control have a number of disadvantages that can be improved by using oligonucleotide insecticides. In this article, we present, for the first time, the results of using oligonucleotide insecticides, for which the target sequence is an internal transcribed spacer (ITS) in a polycistronic rRNA transcript. The mortality of wingless aphid individuals after a Macsan-11 treatment was recorded at a level of 67.15 ± 3.32% 7 days after a single treatment with a solution at a concentration of 100 ng/μL and 97.38 ± 2.49% 7 days after a double treatment with a solution of the same concentration and a daily interval. The contact use of the control oligonucleotide (ACTG)2ACT-11. as well as the oligonucleotide insecticides Macsan-11(3') and Macsan-11(5') was not accompanied by insect mortality. Given the high variability in the internal transcribed spacer, which has proven to be a promising target for the action of oligonucleotide insecticides, it is possible to create selective preparations. This study showed the prospects of ribosomal insect pest genes as targets for the action of olinscides, and also demonstrated the high specificity of such insecticidal agents.

Design and Synthesis of Pyridine and Thiazole Derivatives as Eco-friendly Insecticidal to Control Olive Pests.

Treatment of p-tosyloxybenzaldehyde (1) with ethyl cyanoacetate afforded ethyl 2-cyano-3-(4-{[(4-methylphenyl)sulfonyl]oxy}phenyl)acrylate (2) which reacted with some active methylene derivatives under microwave irradiation in presence of ammonium acetate yielded pyridine derivatives 3-7. On the other hand, when treatment of compound 1 with thiosemicarbazide gave 4-tosyloxybenzylidenethiosemicarbazone (8), which allowed to react with some active methylene compounds, such as: ethyl bromoacetate, chloroacetonitrile or phenacyl bromide derivatives gave thiazole derivatives 9-13. The structure of all products were confirmed by elemental and spectroscopic analyses such as IR, 1 H-NMR, 13 CNMR and mass spectra. The advanced of this method are short reaction time (3-7 min), excellent yield, pure products, and low-cost processing. In the final category, the toxicological characteristics of all compounds were tested towards Saissetia oleae (Olivier, 1791) (Hemiptera: Coccidae). With respect to the LC50 values. It has been found that compound 3 possesses the highest insecticidal bioefficacy compared with other products, with values of 0.502 and 1.009 ppm, for nymphs and adults female, respectively. This study paves the way towards discovering new materials for potential use as insecticidal active agents.

ANALISA PROJECT MANAGEMENT TERHADAP PRODUK ECO ENZYME

Eco Enzyme is a result of organic waste fermentation, derived from leftover fruits, vegetables, sugar, and water. It was first discovered by Dr. Rosukon Poompanvong, a member of the Organic Farming Association from Thailand. Eco Enzyme serves as a versatile liquid for household, agricultural, and livestock purposes. According to an article by Vama & Chekar in 2020, eco enzyme can be utilized as an antifungal, antibacterial, insecticide agent, and cleaner. Some of its functions include being a floor cleaner, dish cleaner, and toilet cleaner.The author created a business around eco enzyme using leftover fruits. The raw materials for eco enzyme are obtained from fruits that are no longer consumable or have become spoiled. Although there have been numerous studies on utilizing leftover fruits for eco enzyme production, not many people in the community are aware of or use eco enzyme. Therefore, the author came up with the idea of a business centered around eco enzyme, both as a value proposition for utilizing leftover fruits and as a means to educate people who are unfamiliar with eco enzyme.

In silico Comparative Analysis of Gene and Protein of Plant Lectins

Lectins are a family of proteins that can recognize and bind specific carbohydrates. Plant lectins play various roles in plant defense and can be utilized as insecticidal, antibacterial, antifungal, and antiviral agents. This study compares genes, proteins, and carbohydrate-binding motifs between 15 plant lectins using in silico methods. The lectin genes of Artocarpus hypargyreus Hance, Hordeum vulgare var. Betzes, Triticum aestivum L. cv. Marshall, Galanthus nivalis L., Allium sativum L., Phaseolus vulgaris, Lens culinaris subsp. tomentosus, Robinia pseudoacacia, Glycine max, Cicer arietinum, Pisum sativum, Canavalia ensiformis, Amaranthus caudatus, Amaranthus hypochondriacus, and Musa acuminata subsp. malaccensis were obtained from National Center for Biotechnology Information and Banana Genome Hub. The gene comparison results revealed different characteristics of the 15 plant lectin genes, with A. hypargyreus having the shortest lectin gene and G. max having the longest. Overall, the 15 plant lectin genes have 1–3 exons. Domain predictions revealed the presence of five domains: jacalin, chitin_bind_1, B_lectin, legume lectin, and agglutinin. Furthermore, there were 2 protein sequences from the jacalin domain, 2 protein sequences from the chitin_bind_I domain, 2 protein sequences from the B_lectin domain, and 4 protein sequences from the legume lectin domains that have complete carbohydrate-binding motifs compared to consensus motifs from literature. The data obtained from this study has not been previously reported and can be utilized for future lectin protein production with synthetic biology approaches. This method will allow scientists to obtain plant bioparts for lectin production using a heterologous system, even without plant samples.

Potential insecticidal extracts from Artocarpus lacucha against Spodoptera litura (Lepidoptera: Noctuidae) larvae.

Artocarpus lacucha, a plant in the Moraceae family, has traditionally been used in Southeast Asian medicine to treat various ailments. This study investigated the insecticidal potential against Spodoptera litura of several compounds extracted from A. lacucha using a topical application method. A sequential extraction method was employed with A. lacucha stems to identify the most toxic crude extract by using hexane, dichloromethane, ethyl acetate, and methanol solvents. Subsequently, the most toxic crude extract was analyzed for chemical composition by HPLC, followed by the isolation process. Among these crude extracts, the ethyl acetate crude extract was the most toxic to second-instar S. litura larvae (24-h LD50 value of ~9.07 µg/larva). Our results showed that the catechin isolated from the ethyl acetate crude extract exhibited the highest toxicity against this insect (24-h LD50 value of ~8.37 µg/larva). Additionally, catechin significantly decreased the activities of acetylcholinesterase, carboxylesterases, and glutathione S-transferase in the larvae. These findings suggest that catechin isolated from A. lacucha could be a potential insecticidal agent against S. litura. However, the toxicity and persistence of catechin under field conditions need to be further investigated to develop this novel insecticide.

A termiticidal and high denaturation-resistant lectin from Moringa oleifera seed cake

Moringa oleifera seed cake contains a lectin named WSMoLC, which was previously described as an insecticidal agent against the yellow fever mosquito Aedes aegypti. In this study, we evaluated the structural stability of WSMoLC against denaturation by chemical and physical agents, as well as its insecticidal activity against the termite Nasutitermes corniger. Conformational alterations of WSMoLC, when in the presence of urea or whilst subjected to heating or high pressures were monitored by circular dichroism and fluorometric analysis. Termiticidal activity was evaluated by supplying the insects with a diet of varying concentrations of WSMoLC. The effects of WSMoLC on insect digestive enzymes activities were also determined. Treatment with urea at concentrations of 4 M or less led to a conformational rearrangement of WSMoLC, as hydrophobic surfaces had less exposure to water. However, at urea concentrations more than 4 M the hydrophobic pockets of WSMoLC experienced greater exposure to water resulting in a 50 % loss of secondary structure. When subjected to heating of up to 65 °C or pressures up to 2.7 kbar, no conformational changes were detected. WSMoLC was shown to display insecticidal activity for N. corniger workers and soldiers (LC50 of 0.292 and 0.637 mg/mL, respectively). It was shown from gut extracts of these insects that the lectin inhibited exoglucanase and endoglucanase enzymes. In conclusion, WSMoLC can be explored as an alternative for termite control because of its high structural stability and ability to withstand denaturation.

Design, synthesis, and insecticidal activity of pyrimidinamine derivatives containing 2‐pyridinyloxy moiety

AbstractAphis fabae is a widespread pest that has more than 200 hosts in the world, belongs to hemiptera, for stinging suction mouthparts, harm buds, young leaves, and flower buds. Pyrimidine derivatives have the advantages of insecticidal, bactericidal, herbicidal, regulating plant growth and other biological activities, and have a unique mechanism of action. Pyrimidinamine derivatives, one of pyrimidine derivatives, were reported as early as 1955, and all the world's major pesticide companies (Syngenta, Dow Yinon, Bayer, DuPont, and BASF) have carried out research studies, which had lasted for nearly 60 years. For example, commercial pyrimidine products such as flupyrimethanil (fungicide) and pyrimethanil (insecticidal and acaricidal agents) show excellent biological activity. So pyrimidinamine derivatives are considered promising agricultural compounds. In this study, a series of pyrimidinamine derivatives were designed and synthesized using pyrimidifen as a template according to bioisosterism. 5‐chloro‐N‐(1‐((3‐chloro‐5‐(trifluoromethyl)pyridin‐2‐yl)oxy)‐2‐methylpropan‐2‐yl)‐ 6‐ethylpyrimidin‐4‐amine, T23, had the best control effect on Aphis fabae with LC50 values of 1.46 mg/L, versus commercial insecticides spirotetramat and imidacloprid (2.45 and 0.53 mg/L). The synthesis, characterization, and activity data of the compounds are presented in the text, and the structure–activity relationships are discussed.

Wood Vinegar as an Alternative Insecticide in Controlling Rice Weevil, Sitophylus oryzae (Coleoptera: Curculionidae)

Rice production faces many challenges including damages due to pest infestation in storage after harvest. Stored rice grains are often under threat and damage from pests such as rice weevil which resulted in reduction of the quality and quantity. Application of chemical insecticides helps to control this pest, however, it gives negative impacts to the environment and human health. Application of plant-based insecticides including the use of wood vinegar can become an alternative to the conventional method. This work describes the effectiveness of wood vinegar as bioinsecticide to inhibit the rice weevil’s activity by assessing the repellency, mortality and antifeedant activity at different concentration of 50, 100, 150 and 200 rpm. Wood vinegar showed high repellency of 98.3% towards rice weevils at 200 ppm after 5 hours of exposure times. Increased in concentration affects in increased mortality with highest number of 97% recorded at 200 ppm. The lethal concentration (LC) of wood vinegar was calculated to be 77.62 ppm. Antifeedant activity resulted in reduction of weight loss in stored rice with lowest reduction of 2% at 200 ppm. This promising result reflects the ability of wood vinegar as insecticidal agents in management and control of stored-grain pest.

Discovery of Novel Isoxazoline Compounds that Incorporate a para-Diamide Moiety as Potential Insecticidal Agents against Fall Armyworm (Spodoptera frugiperda).

Spodoptera frugiperda is a major migratory agricultural pest, which seriously impedes agricultural production around the world. To discover potent compounds against S. frugiperda, a number of novel isoxazoline derivatives were designed and synthesized and created on account of the identified lead compound F32 (4-(5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-2-methyl-N-(3-propionamidophenyl)benzamide). Based on the three-dimensional quantitative structure-activity relationship of those compounds, the compound G22 (N-(4-acetamidophenyl)-4-(5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-2-methylbenzamide) was developed. A bioassay showed that G22 is highly lethal to S. frugiperda (LC50 = 1.57 mg/L), a more effective control than insecticides fipronil (LC50 = 78.8 mg/L) and chlorantraniliprole (LC50 = 1.60 mg/L). Field trials were also implemented to identify candidate agents. Furthermore, from the insect γ-aminobutyric acid (GABA) enzyme-linked immunosorbent assay, it is obvious that G22 could up-regulate the expression of GABA of insects, which showed a similar result to fipronil. The analysis of molecular docking exhibited that the hydrophobic effect and hydrogen bonds play key roles in the combination between G22 with GABA receptors. This study provides a potent isoxazoline candidate compound for the S. frugiperda control.

Potentials of Artocarpus altilis latex lectin (AaLL) as an antiproliferative, nematicidal, and insecticidal agent

Introduction and Aim: Plants are the most accessible and convenient source of lectins. Artocarpus altilis is a Moraceae plant utilized for its latex. The anti-proliferative, nematicidal, and insecticidal effects of this plant latex are unknown. The current study evaluates the antiproliferative, nematicidal, and insecticidal activity of pure AaLL on Triple Negative Breast Cancer cells, Meloidogyne incognita, and Spodoptera frugiperda, respectively.
 
 Materials and Methods: To assess AaLL's antiproliferative activity against MDA-MB-231, MTT and wound healing experiments were performed. Using juvenile mortality and feeding assays, the in vitro nematicidal and insecticidal activity against Meloidogyne incognita and Spodoptera frugiperda were evaluated.
 
 Results: The MTT experiment demonstrated that 5.4µg/ml AaLL effectively inhibited MDA-MB-231 growth by 50% compared to the control. Even at 40µg/ml, AaLL had no cytotoxic effects on NIH3T3 fibroblast cells. AaLL significantly reduced cell migration, with the wound area remaining at 41.95 percent as opposed to 4.57 percent in the control group. In vitro results on J2s exposed to AaLL for 72 hours demonstrated a death rate of 52% at a concentration of 30µg/ml. After 24 hours of incubation with 400µg/ml lectin, the insecticidal tests reveal that AaLL considerably reduces the weight of larvae. After 48 hours, a lectin concentration of 0.04% caused 69.44% larval death.
 
 Conclusion: This is the first report demonstrating the latex lectin from Artocarpus altilis's anti-proliferation, anti-migration, nematicidal, and insecticidal properties. Further research will be done on the signaling pathways and mechanism of action linked to these features.

Salvia sclarea Essential Oil Chemical Composition and Biological Activities.

Salvia sclarea essential oil (SSEO) has a long tradition in the food, cosmetic, and perfume industries. The present study aimed to analyze the chemical composition of SSEO, its antioxidant activity, antimicrobial activity in vitro and in situ, antibiofilm, and insecticidal activity. Besides that, in this study, we have evaluated the antimicrobial activity of SSEO constituent (E)-caryophyllene and standard antibiotic meropenem. Identification of volatile constituents was performed by using gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) techniques. Results obtained indicated that the main constituents of SSEO were linalool acetate (49.1%) and linalool (20.6%), followed by (E)-caryophyllene (5.1%), p-cimene (4.9%), a-terpineol (4.9%), and geranyl acetate (4.4%). Antioxidant activity was determined as low by the means of neutralization of the DDPH radical and ABTS radical cation. The SSEO was able to neutralize the DPPH radical to an extent of 11.76 ± 1.34%, while its ability to decolorize the ABTS radical cation was determined at 29.70 ± 1.45%. Preliminary results of antimicrobial activity were obtained with the disc diffusion method, while further results were obtained by broth microdilution and the vapor phase method. Overall, the results of antimicrobial testing of SSEO, (E)-caryophyllene, and meropenem, were moderate. However, the lowest MIC values, determined in the range of 0.22-0.75 µg/mL for MIC50 and 0.39-0.89 µg/mL for MIC90, were observed for (E)-caryophyllene. The antimicrobial activity of the vapor phase of SSEO (towards microorganisms growing on potato) was significantly stronger than that of the contact application. Biofilm analysis using the MALDI TOF MS Biotyper showed changes in the protein profile of Pseudomonas fluorescens that showed the efficiency of SSEO in inhibiting biofilm formation on stainless-steel and plastic surfaces. The insecticidal potential of SSEO against Oxycarenus lavatera was also demonstrated, and results show that the highest concentration was the most effective, showing insecticidal activity of 66.66%. The results obtained in this study indicate the potential application of SSEO as a biofilm control agent, in the shelf-life extension and storage of potatoes, and as an insecticidal agent.

Comparative study of three plant-derived extracts as new management strategies against Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Finding innovative eco-friendly agents for pest control may be aided by investigating the plant-derived extracts’ properties on economic pests. Therefore, the insecticidal, behavioral, biological and biochemical effects of Magnolia grandiflora (Magnoliaceae) leaf water and methanol extracts, Schinus terebinthifolius (Anacardiaceae) wood methanol extract, and Salix babylonica (Salicaceae) leaf methanol extract in comparison with a reference insecticide novaluron against S. littoralis were evaluated. The extracts were analyzed by High-Performance Liquid Chromatography (HPLC). The most abundant phenolic compounds were 4-hydroxybenzoic acid (7.16 mg/mL) and ferulic acid (6.34 mg/mL) in M. grandiflora leaf water extract; catechol (13.05 mg/mL), ferulic acid (11.87 mg/mL), and chlorogenic acid (10.33 mg/mL) in M. grandiflora leaf methanol extract; ferulic acid (14.81 mg/mL), caffeic acid (5.61 mg/mL), and gallic acid (5.07 mg/mL) In the S. terebinthifolius extract; cinnamic acid (11.36 mg/mL), and protocatechuic acid (10.33 mg/mL) In the methanol extract from S. babylonica extract. S. terebinthifolius extract had a highly toxic effect against second larvae after 96 h and eggs with LC50 values of 0.89 and 0.94 mg/L, respectively. Despite M. grandiflora extracts didn’t show any toxicity against S. littoralis stages, they had an attractant effect on fourth- and second larvae, with feeding deterrence values of − 2.7% and − 6.7%, respectively, at 10 mg/L. S. terebinthifolius extract significantly reduced the percentage of pupation, adult emergence, hatchability, and fecundity, with values of 60.2%, 56.7%, 35.3%, and 105.4 eggs/female, respectively. Novaluron and S. terebinthifolius extract drastically inhibited the activities of α-amylase and total proteases to 1.16 and 0.52, and 1.47 and 0.65 ΔOD/mg protein/min, respectively. In the semi-field experiment, the residual toxicity of tested extracts on S. littoralis gradually decreased over time compared to novaluron. These findings indicate that extract from S. terebinthifolius is a promising insecticidal agent against S. littoralis.

Effects of Piper nigrum L. Fruit Essential Oil Toxicity against Stable Fly (Diptera: Muscidae).

The efficacy of Piper nigrum L. fruit essential oil (EO) against Stomoxys calcitrans (stable fly), a blood-feeding fly distributed worldwide, was investigated. This study aimed to evaluate the insecticidal activity of EO based on contact and fumigant toxicity tests. Chemical analysis of the EO using gas chromatography-mass spectrometry revealed that sabinene (24.41%), limonene (23.80%), β-caryophyllene (18.52%), and α-pinene (10.59%) were the major components. The results demonstrated that fly mortality increased with increasing EO concentration and time during the first 24 h of exposure. The median lethal dose was 78.37 µg/fly for contact toxicity, while the 90% lethal dose was 556.28 µg/fly. The median lethal concentration during fumigant toxicity testing was 13.72 mg/L air, and the 90% lethal concentration was 45.63 mg/L air. Our findings suggested that essential oil extracted from P. nigrum fruit could be a potential natural insecticidal agent for control of stable fly. To examine the insecticidal properties of P. nigrum fruit EO, further field trials and investigation into the efficacy of nano-formulations are required.