Repellent Effect Research Articles

Insecticidal Effect of Two Chemotypes of the Essential Oil of Eucalyptus camaldulensis Dehnh against Aphis fabae Scopoli

Background: The objective of this study was to study the insecticidal and repellent effect of the essential oil of the plant Eucalyptus camaldulensis Red Dehnh extracted by hydrodistillation method planted in the Ouargla region against the black aphid. Methods: The insecticidal effect of essential oils against aphid mortality by the introduction of bean leaflets in the different oily extracts with different concentrations and the count of dead individuals after 3, 6 and 24 h at the physiology laboratory in Ghardaïa University. Result: Through this study, the leaves treated with the major compounds of Eucalyptus camaldulensis essential oil such as Benzene,1-methyl-4-(1-methylethyl) at 35 per cent concentration after 24 hours, a 65 per cent aphid mortality was recorded which is more effective compared to Sabinene and essential oils of Eucalyptus camaldulensis at different concentrations (5; 35%; and 50 per cent). As for the repellent effect is 87 per cent after 6 hours for the pure essential oil of E. camaldulensis.

Tailoring asymmetric wettability of Janus nanofiber membranes for directional oil transport and oil capture from oil/water mixtures and oil-in-water emulsions

The separation of oil from oil-in-water emulsions is crucial for the recycling of valuable resources. Janus membranes, characterized by their asymmetric configuration, have shown promise in capturing oil from these emulsions due to their ability to efficiently catch micro-size oil droplets with competitive flux rates, minimal energy costs, and fouling-free operations. This study explored the impact of asymmetric wettability on the oil capture capabilities of Janus nanofiber membranes (JNMs). The wettability of the JNMs’ skin layer was modified from oleophilic, with an oil contact angle (OCA) of ∼0°, to oleophobic, with an OCA of ∼142.7°. This adjustment significantly influenced the oil capture process. The oleophobic skin layer acted as a barrier, reducing oil permeation flux from the feed side. However, this same repellent effect facilitated the directional transport of oil once it breached the skin layer. Interestingly, this led to divergent outcomes in the JNMs’ ability to capture oil from oil/water mixture versus oil-in-water emulsion, a distinction not reported in previous studies. These findings are expected to contribute to the enhancement of Janus membranes, optimizing them for more efficient oil recovery from both oil/water mixture and oil-in-water emulsion.

Insecticidal Properties and Chemical Characterization of Laurus nobilis L. Essential Oils from Two Regions of Morocco against Callosobruchus maculatus (Coleoptera: Bruchinae)

Morocco is a significant botanical reservoir that boasts a wealth of raw materials with promising applications across various industrial sectors, notably in pharmaceuticals and food. The objective of this study was to assess the effectiveness of essential oils (EOs) derived from Laurus nobilis L. leaves originating from the Tanger (EOT) and Meknes (EOM) regions in combating Callosobruchus maculatus infection. The chemical compositions of these oils were examined using Fourier transform infrared (FTIR) spectroscopy and gas chromatography–mass spectrometry (GC-MS). The biological activity of the EOs was evaluated via repulsion and fumigation tests against C. maculatus at varying concentrations. FTIR analysis revealed distinct vibrational bands indicative of various chemical compounds. GC-MS analysis was used to delineate the major chemical constituents of the EOs. The three predominant compounds in the EOT were 1,8-cineole (37.64%), linalool (16.40%), and adamantane (12.00%), whereas 1,8-cineole (47.84%), toluene (17.60%), and α-phellandrene (8.44%) were the most abundant in the EOM. Notably, the EOs exhibited significant repellent activity against C. maculatus, with repulsion percentages ranging from 51.11 to 90.00% in Tanger and 67.78 to 93.33% in Meknes. Mortality rates varied from 0 to 100% depending on the treatment. However, the mean concentrations showed mortality rates ranging from 29.44 to 65.56% for the EOT and from 21.11 to 67.78% for the EOM, with LD50 values of 11.96 μL/L and 5.22 μL/L. Docking studies revealed that 1,8-cineole had the highest binding affinity for the active site of acetylcholinesterase, thus confirming its toxic activity against C. maculatus. The findings of this study highlight the ability of EOs extracted from L. nobilis in the Moroccan regions of Tanger and Meknes to act as effective insecticides and repellents against C. maculatus, thereby highlighting avenues for further exploration of pest management and agricultural practices.

Exploring chemical composition and insecticidal activities of Alpinia calcarata rhizome essential oil against three major storage insects

Alpinia calcarata (Roscoe), generally recognized as snap ginger or lesser galangal of the Zingiberaceae family, undergoes widespread cultivation in tropical nations. It is characterized by its noteworthy pharmacological attributes, such as anti-inflammatory, analgesic, antinociceptive, reproductive, anti-cancer, and gastro-protective effects. Many storage pests now resist traditional chemical pesticides. Transitioning to organic alternatives is a preferable and sustainable solution. This research investigates the insecticidal activity of essential oil from A. calcarata rhizomes, obtained via hydro-distillation. Chemical analysis was conducted, and the study assessed its toxicity and repellent effects on Tribolium castaneum (Herbst), Lasioderma serricorne (F.), and Callosobruchus chinensis (L). A yield of 0.44 ± 0.02 % essential oil was obtained from dry rhizomes. Gas chromatography-mass spectrometry (GC-MS) characterization revealed the major chemical constituents as 1,8-cineole (25.71 %), ethyl iso-allocholate (16.01 %), and fenchyl acetate (15.15 %). The findings from the investigation into the pesticidal characteristics of essential oils derived from the rhizome of A. calcarata unveiled significant contact (LC50 at 24 h was 10.9 mg/cm2 for T. castaneum, 1.0 mg/cm2 for L. serricorne and 0.5 mg/cm2 for C. chinensis) and fumigant toxicity (LC50 at 24 h was 4.05 mg/L air for T. castaneum, 1.75 mg/L air for L. serricorne, and 1.03 mg/L air for C. chinensis). The repellent efficacy was evaluated through an area preference test, revealing robust repellent activity at various concentrations. Undoubtedly, the essential oil extracted from the rhizome of A. calcarata is valuable and has the potential to be a safe, organic pesticide for controlling storage pests.

Odourless vegetable oils as insect pest repellents for short-term protection of various food packaging materials

The repellent activity of two odourless vegetable oils (sweet almond—SAO and soybean—SO) applied on filter paper and four types of food packaging materials (polyethylene film, plastic gunnysacks, cardboard, and wood) was tested against three species of stored product pests (Sitophilus granarius, Tribolium castaneum, and Oryzaephilus surinamensis). The repellence of three doses was evaluated after 24 h, and after 7, 14, 21, and 28 days. Both oils exhibited a repellent effect when applied to filter paper, but this effect decreased with time and concentration. The most susceptible species was T. castaneum. The maximum repellence was 84% and 76% for SO and SAO, respectively. On packaging materials, the repellent effect diminished after a certain period of time, ranging from 7 to 28 days. Subsequently, the oils even became attractive. Generally, the repellent effects of both SO and SAO were higher on cardboard and wood slab than on polyethylene film and plastic gunnysacks. As such, in the case of SO, the repellence against T. castaneum was 88% 24 h after application on cardboard, whilst 68% on plastic bag. This work demonstrated the repellent potential of vegetable oils in the short term for the protection of packaged food against stored product pests.

The repellent effects of eight Chinese herbal essential oils on red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae), and analysis of active components

The red imported fire ant (RIFA), Solenopsis invicta Buren, is an invasive pest that is extremely aggressive and thus poses a strong threat to human health, agricultural production, equipment and the environment. In this study, we evaluated the repellent effects of eight Chinese herbal essential oils (EOs) on RIFAs, and identified the main repellent components in the EOs. Results showed that all eight EOs had outstanding repellency to RIFAs, among which A. argyi and S. album EOs had the strongest repellent effects on RIFAs. GC-MS revealed 34 ingredients in A. argyi EO, among which sesquiterpenoids and their oxygenated derivatives accounted for the greatest proportion (50 %), followed by monoterpenes and their oxygenated derivatives (47.06 %) and unknown components (2.94 %). Dipentene, 1-caryophyllene, p-cymene, α-terpineol, and Δ-cadinene were the most abundant compounds. A total of 61 ingredients were identified in S. album EO, including monoterpenes and their oxygenated derivatives (40.98 %), sesquiterpenoids and their oxygenated derivatives (39.34 %), diterpenoids and their oxygenated derivatives (3.28 %), aromatic compounds (3.28 %), and unknown components (13.12 %). Among them, the most abundant compounds were diethyl phthalate, α-cetone, 2-phenylethanol and sandacanol. The GC-EAD results showed that RIFA workers exhibited strong electroantennographic responses to dipentene, α-terpineol and 1-caryophyllene from A. argyi EO, as well as to linalool, 2-phenylethanol and benzyl acetate from S. album EO. Furthermore, all of the above six ingredients had significant repellent effects against RIFAs based on behavioral experiments. In conclusion, A. argyi and S. album EOs have good repellent effects on RIFAs, and the active ingredients include dipentene, α-terpineol, 1-caryophyllene, linalool, 2-phenylethanol and benzyl acetate. Our findings provide new information for the development of green, safe, and efficient repellents against RIFAs.

Repellent and Attractant Effect of the Nettle Plant Urtica dioica on the Larvae of the Greater Wax Moth Galleria mellonella L. (Lepidoptera: Pyralidae)

Repellent and Attractant Effect of the Nettle Plant Urtica dioica on the Larvae of the Greater Wax Moth Galleria mellonella L. (Lepidoptera: Pyralidae)

In vivo mosquito repellency effect of citronella (Cymbopogon nardus (L.) Rendle) essential oil bath bomb formulation in dogs.

Mosquitoes carry numerous diseases of medical and veterinary significance. While citronella essential oil is safe as a mosquito repellent, extensive research does not document its ability to deter mosquitoes from animals. This study assessed the citronella essential oil bath bomb's ability to repel Culex quinquefasciatus mosquitoes in dogs. Citronella essential oil's chemical composition was analyzed using gas chromatography-mass spectrometry (GC-MS). Through freeze-thaw testing, a bath bomb formulation containing 6% w/w citronella essential oil was assessed for its physical and chemical stability. Thirty-two healthy client-owned mixed-breed dogs were employed to test the mosquito-repellency effects of citronella essential oil (treatment group) and olive oil (control group) bath bomb formulations. Bath bombs were tested for irritation effects on animal skin for 15-day post-application. Thirty-six compounds were identified through GC-MS, with citronellal (23.38%), δ-cadinene (12.25%), and geraniol (9.09%) being the most prevalent constituents. The bath bomb maintained its original physical properties after undergoing six freeze-thawing cycles and retained over 90% of its citronella essential oil. About 100%, 69.28%, and 65.58% mosquito repellency were displayed by the citronella essential oil bath bomb at 3 h, 6 h, and 8 h, respectively. None of the test animals exhibited skin irritation during the study. The citronella bath bomb effectively repelled C. quinquefasciatus in dogs without irritating their skin. The formulation's physical and chemical stability is demonstrated by the results of freeze-thaw stability testing. Further studies should be conducted to evaluate the repelling activity against other mosquito species.

Morinda citrifolia Essential Oil: A Plant Resistance Biostimulant and a Sustainable Alternative for Controlling Phytopathogens and Insect Pests.

With the growing demand for sustainable and safe agricultural practices, plant compounds emerge as a solution for biological activities. Here, we evaluated the potential of using Morinda citrifolia essential oil to induce plant resistance and to control phytopathogens (Curvularia lunata) and insect pests (Daubulus maidis). We conducted a chromatographic analysis to unveil the essential oil components. We also quantified the activity levels of antioxidant enzymes and chitinase for resistance induction. The antifungal action was evaluated through disease progression and the inhibition of mycelial growth in addition to in silico studies that made it possible to predict the interaction site between the fungal protein and the compounds. We assessed the toxicity and repellent actions towards the D. maidis. Octanoic acid (58.43%) was identified as the essential oil major compound. Preventive treatment with essential oil and octanoic acid (25.0 µL mL-1) increased not only the plant defense activities (i.e., the activity of the enzymes superoxide dismutase, catalase, phenol peroxidase, ascorbate peroxidase, and chitinase) but also controlled Curvularia leaf spot. The stable interactions between octanoic acid and tyrosine-tRNA ligase from C. lunata suggested protein synthesis inactivation. The essential oil inhibited 51.6% of mycelial growth, and this effect was increased to 75.9% with the addition of adjuvants (i.e., angico gum). The essential oil reduced 76% of the population of D. maidis adults and repelled 50% of the number of D. maidis after 48 h under field conditions. The repellency effect in the field reduced the population of D. maidis adults, transmitters of the stunting complex, by 50%. The results highlight the potential of M. citrifolia as a resistance activator, fungicide, insecticide, and an effective biorational alternative.

Olfactory repellents decrease the number of ungulate-vehicle collisions on roads: Results of a two-year carcass study

An experimental study was conducted to test the effectiveness of olfactory repellents (ORE) as a mitigation measure to reduce ungulate-vehicle collisions (UVC). In the first phase, an extensive field survey was undertaken while employing the Before-After Control-Impact (BACI) study design. On the basis of ungulate mortality, 134 road sections were monitored on foot along both roadsides once a week. The monitoring lasted fourteen weeks per year in both 2021 (Before period) and 2022 (After period). In the after period, 2022, ORE were applied within the impact segments. The second phase consisted of data verification and statistical analysis. The data revealed a decrease in UVC of 68%. The confidence interval of this estimate suggested, however, a great deal of uncertainty about the true value. Therefore, the data were pooled, and the Bayesian inference was applied. On the level of moderate evidence, ORE decreased the number of UVC by at least 43% and at most 60%. We also observed that the ORE effect was more pronounced in the first seven weeks after installation than in the following seven weeks, suggesting ungulate habituation to ORE. We have therefore concluded that for a short period (ideally corresponding to UVC peaks) ORE could be considered an effective safety measure for secondary roads.

Pharmacological and Phytochemical Potential of Andropogon muricatus: A Review

Many medicinal plants have been utilized as medications since ages ago. Chemical components extracted from such plants have been used historically in traditional Unani medicine, the Siddha and other medical systems for a variety of ailments. Among them is Andropogon muricatus, a member of the family Poaceae, better known by its common name, vetiver. It contains a variety of organic components with significant therapeutic benefits for a range of illnesses, including mosquito repellent, anxiolytic, acaricidal, hypoglycaemic, antidepressant, antidiuretic, sedative, antifungal, and nervine effects. This plant’s roots serve as cooling. When it comes to oil extraction—which is used in food and beverages, spas, home appliances, and medicine—root systems are the most valuable parts of the plant. It is indigenous in Bangladesh, China, Japan, the Bonin Islands, Nepal, the Philippines, and Sri Lanka in the Asian continent. Australia and Spain were first exposed to it in Europe and Oceania. Substances of a chemical nature that have been extracted from the plant’s overall various sections have previously been the subject of numerous pharmacologic and medicinal studies.

Studying the effectiveness of Jatropha carcus L. Extract as a repellent, antifeedant, and toxic substance against red palm weevil (Rhynchophorus Ferrugineus) adult insects in Saudi Arabia

ObjectiveRed palm weevil (RPW), Rhynchophorus ferrugineus, is a highly harmful pest that causes severe damage to date palm trees. The detrimental influence of RPW on date palm trees cannot be ignored and must be addressed. Chemical insecticides are available for controlling RPW; however, the insect population has become resistant to these chemicals, leading to damage and spread to new areas. The present investigation examined the impacts of physic nut (Jatropha curcas L.) seeds essential oils (PNEO) on laboratory-reared RPWs adult insects reared in a controlled laboratory environment. MethodsThe insecticidal, repellent, and antifeedant potentials of different doses (10, 20, 30, 40, 50%) of PNEO were tested against RPW. The insecticidal activity of J. curcas seeds oil extracts was assessed using topical application and feeding methods. ResultsRPW showed a high mortality rate when J. curcas seeds oil was applied topically after 24 h (P < 0.05). The mortality (%) of insects was 8, 76, 92, 96, and 100 for 10 %, 20 %, 30 %, 40 %, and 50 % concentrations, respectively. The LC50 and LC90 were 16.50 %, and 28.14 %, respectively. Results from the feeding method demonstrated a significant increase in mortality with a 100 % mortality rate at higher concentrations of PNEO compared to 10 and 20 % concentrations (P < 0.0001). The LC50 and LC90 were 24.42 % and 31.30 %, respectively. There was no significant decrease in food consumption and the antifeedant index when 10 % and 20 % of J. curcas seeds oil were used on the 3rd and 6th day after application. All J. curcas oil concentrations showed a repellent effect significantly higher than the controls (P < 0.05). ConclusionJ. curcas seeds oil has shown potential insecticidal and repellent effects against RPW, and it could provide an eco-friendly tool for RPW pest management.

Insecticidal activity of Aguaria salicifolia leaf extracts on cowpea bruchid Callosobruchus maculatus (Coleoptera: Chrysomelidae)

The protection of foodstuffs against insect pests constitutes a serious problem across the world. Synthetic chemical insecticides are the most widely used method for grain protection. Unfortunately, the harmful effects of these insecticides on human health and environment have increased the interest of researchers for botanical insecticides which are recognized as eco-friendly products. Therefore, the efficacy of Aguaria salicifolia Hook. f. ex Oliv. leaf extracts was tested against Callosobruchus maculatus F. on cowpea grain, at the dosage of 2, 4, 8 and 16 g/kg. To estimate the biological activity of leaf powder and aqueous extract, adult mortality, insect population growth reduction, grain damage and weight loss reduction tests were carried out. The repellency effect of A. salicifolia was assessed using the aqueous, methanolic and ethyl acetate extracts. The mortality was recorded at 1, 3, 5 and 6 days post-exposure. All treatments were submitted to four replications, and the experiment was carried out in a completely randomised design in the fluctuating laboratory conditions (Temp. = 23.71 ± 1.03 °C; RH. = 81.38 ± 2.03 %). Overall, all the extracts significantly exhibited insecticidal activities against cowpea bruchids. The highest dosage induced the highest mortality rates; 79.26 % and 84.08 % with aqueous extract and leaf powder, respectively. The different plant extracts considerably reduced insect population, grain damage and weight loss. The complete reduction of C. maculatus population was achieved by aqueous extract of A. salicifolia. The different solvent extracts had repellent property with repellency percentage values ranging from 30 % to 73.75 %. Considering these results, insecticidal products derived from A. salicifolia could constitute an alternative to the chemical synthetic insecticides used against C. maculatus. However, further studies are needed to be carried out concerning the mammalian toxicity and evaluation of suitable formulations of the extracts under field conditions before their promotion for grain protection.

Repellent potential of agroecological extracts: Exploring their efficacy against the leaf‐cutting ant Acromyrmex subterraneus in the laboratory

AbstractThe increasing restrictions on commercial toxic baits for controlling leaf‐cutting ants have started a “gold rush” for alternative compounds, with agroecological extracts emerging as a promising option. Here, we tested for the first time the repellent effects of concentrated and diluted ant extracts and cow urine solution on laboratory colonies of Acromyrmex subterraneus (Forel) (Hymenoptera: Formicidae). The agroecological extracts preparation and application followed the information provided by peasants from the Movimento dos Trabalhadores Rurais Sem Terra in Brazil who carry out agroecology. First, we applied the agroecological extracts in the middle segment of the upper path of a foraging trail to determine whether they act as a chemical barrier. All agroecological extracts induced the deviation of the foraging flow from the upper path to the lateral path. However, only the concentrated ant extract reduced the leaf delivery rate. Also, we applied the agroecological extracts directly on the leaf disks and conducted a paired selection test. The proportion of transported leaf disks with concentrated ant extract and cow urine solution was lower than that of control disks. We suggest that the observed repellent efficacy of the concentrated ant extract may stem from its content of chemical compounds belonging to the same chemical group as the alarm pheromones found by other Acromyrmex species. As for the cow urine solution, we attribute its repellent effect to the presence of urea. Our findings highlight a significant repellent potential of the concentrated ant extract and cow urine solution for leaf‐cutting ants, which may be applied both on foraging trails and on leaves of cultivated plants.

Activity of Rosmarinus officinalis (Lamiales: Lamiaceae) Essential Oil and Its Main Constituent, 1,8-Cineole, against Tribolium castaneum (Coleoptera: Tenebrionidae)1

Abstract Rosemary essential oil (EO), from Rosmarinus officinalis L. (Lamiales: Lamiaceae), has potent properties against stored insect pests. This study aimed to evaluate the efficacy of EOs from both manually extracted and commercially produced R. officinalis, as well as the main compound 1,8-cineole, against adults of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Chemical analysis of the R. officinalis EOs was conducted using a gas chromatograph–mass spectrometer. Toxicity and repellent effects were assessed through contact and fumigation bioassays in a factorial experimental design with five replicates. Each R. officinalis EO type showed nine major compounds (&amp;gt;90%), with 1,8-cineol as the predominant component (&amp;gt;52%). Contact toxicity bioassays showed 1,8-cineole had a median lethal concentration of 1.12% at 48 h, 1.54% for manually extracted EOs, and 1.64% for commercially produced R. officinalis EOs. Furthermore, 0.5% of 1,8-cineole displayed strong contact efficacy against T. castaneum. Fumigant toxicity was observed at 140.07, 127.28, and 121.52 μl/L air, respectively. Manually extracted EO at 160 μl/L air demonstrated strong fumigant efficacy against T. castaneum, acting as a contact (66–94%) and fumigant (82–69%) repellent within 8 h, outperforming commercially produced EO and 1,8-cineole. These findings highlight the potential of manually extracted EO from R. officinalis as a natural insecticide, effective in both contact and fumigation against T. castaneum. This offers a promising avenue for using plant extracts in storage pest prevention, potentially leading to the development of insecticide products.

Silk fibroin catheter with stable bioinspired inner-surfaces for inhibition of bioadhesion

Biofilm formation on indwelling medical devices such as catheters and ventilators due to the adhesion of bacteria poses significant challenges in healthcare. Surface modification with micro- and nano-structures offers a promising strategy to prevent bioadhesion and is safer than surface chemical modification approaches. Here, catheters were prepared using silk fibroin (SF) hydrogels and an infusion molding method, with the inner surface featuring a micropapillae structure inspired by lotus leaves (SF-CMP). After phenylethanol (PEA) fumigation treatment, the resulting catheters (SF-CMP PEA) displayed improved swelling resistance and mechanical properties compared to methanol-treated catheters (SF-CMP MeOH). PEA was more efficient than methanol in controlling the size, distribution, and content of silk crystalline β-sheet blocks and thus the swelling and mechanical properties. Moreover, the micro-papillae structure on SF-CMP PEA remained stable over 35 days in solution, in contrast to SF-CMP MeOH, which lasted <7 days. SF-CMP PEA exhibited repellent effects against E. coli and S. aureusin vitro, and low cytotoxicity to the endothelial cells cultured on the unpatterned surface. Additionally, subcutaneous implantation studies showed reduced inflammation around the micropatterned samples compared to controls with a plain, unpatterned surface. The unique properties of SF-based materials, including tunable structures, biocompatibility, degradation, and drug-loading capability make them an attractive material for anti-bioadhesion in applications ranging from indwelling medical devices to tissue engineering scaffolds.

Plasticulture film coextruded with essential oils: sustainable protection of salad crops

ABSTRACT Plasticulture has revolutionised Farming production. In salad cultivation, the snail is the main pest that can cause significant economic losses. The present study focuses on the design of a new industrial mulching material co-extruded separately with three essential oils: cade, turmeric and cumin oil. Experimental tests carried out on a pilot system confirmed the repellent effect against this mollusc and the protection of lettuce weight loss by about 30%. Adhesion tests by Escherichia coli and Pseudomonas aeruginosa demonstrate anti-adhesion properties of 80% when bioactive oils are incorporated into the industrial formulation of the plastic film. Application of the predictive theoretical approach confirms that the adhesion scores cannot be explained by the total adhesion energy and total hydrophobicity energy. This proves that these effects are the result of bioactive activity. This research work offers an innovative, practical and ecologically responsible alternative to protect lettuce crops against nuisances and pests.

Unconventional Dually-Mobile Superrepellent Surfaces.

The ability of water droplets to move freely on superrepellent surfaces is a crucial feature that enables effective liquid repellency. Common superrepellent surfaces allow free motion of droplets in the Cassie state, with the liquid resting on the surface textures. However, liquid impalement into the textures generally leads to a wetting transition to the Wenzel state and droplet immobilization on the surface, thereby destroying the liquid repellency. This study reports the creation of a novel type of superrepellent surface through rational structural control combined with liquid-like surface chemistry, which allows for the free movement of water droplets and effective repellency in both the Cassie and Wenzel states. Theoretical guidelines for designing such surfaces are provided, and experimental results are consistent with theoretical analysis. Furthermore, this work demonstrates the enhanced ice resistance of the dually-mobile superrepellent surfaces, along with their distinctive self-cleaning capability to eliminate internal contaminants. This study expands the understanding of superrepellency and offers new possibilities for the development of repellent surfaces with exceptional anti-wetting properties.

Influence of Endogenous Bacteria on Behavioral Responses in Leptocybe invasa: An Analysis of mVOCs.

Microorganisms within insects play a vital role in maintaining the basal physiological functions of the insects, with olfactory signals as critical components of insect survival strategies. Leptocybe invasa (L. invasa), an invasive alien pest inflicting significant damage to eucalyptus trees, harbors a rich and varied bacterial community within its body. However, the impact of its endogenous bacteria and their microbial Volatile Organic Compounds (mVOCs) on the behavioral preferences of L. invasa remains unexplored to date. This study focused on nine cultivable and dominant endogenous bacterial strains within L. invasa. Using a Y-tube olfactometer, we investigated the behavioral responses of female L. invasa to the mVOCs emitted by these bacteria. Concurrently, gas chromatography-mass spectrometry (GC-MS) was employed to quantify the mVOCs produced by these endogenous bacteria. Our findings revealed that Staphylococcus sp. exhibited the highest attractiveness of L. invasa, whereas Microbacterium sp. and E. cloacae exerted the most significant avoidance effects. The analysis of the mVOCs further highlighted the significance of aldehyde compounds, notably 2,3,6-trichlorobenzaldehyde, and alkane compounds, such as eicosane, in mediating the repellency and attraction effects. These results contribute to a deeper understanding of the invasion mechanism of L. invasa and provide a scientific basis for developing novel biopesticides or elicitors.

Identification and Characterization of Hibiscus mutabilis Varieties Resistant to Bemisia tabaci and Their Resistance Mechanisms.

Hibiscus mutabilis, the city flower of Chengdu, is culturally significant and has nutritional and medicinal benefits. However, frequent infestations of Bemisia tabaci have caused economic losses. This study aimed to identify insect-resistant H. mutabilis varieties. Over two years, varieties like Jinqiusong, Zuiyun, and Zuifurong showed moderate to high resistance based on reproductive indices. Assessments of antixenosis and developmental impacts revealed that adult B. tabaci exhibited low selectivity toward these resistant varieties, indicating a strong repellent effect. Gas chromatography-mass spectrometry analysis identified volatile organic compounds, such as alcohols, alkanes, and terpenes. Notably, 2-ethylhexanol and 6-methylheptanol exhibited repellent properties. Using nontargeted metabolomics, this study compared the metabolite profiles of the insect-resistant variety Jinqiusong (JQS), moderately resistant Bairihuacai (BRHC), and highly susceptible Chongbanbai (CBB) post B. tabaci infestation. Fifteen key metabolites were linked to resistance, emphasizing the phenylpropanoid biosynthesis pathway as crucial in defense. These findings offer a theoretical foundation for breeding insect-resistant H. mutabilis varieties and developing eco-friendly strategies against B. tabaci infestations.