Insecticidal Activity Of Essential Oil Research Articles

Insecticidal activity of essential oils and plant extracts on cowpea aphid

Aphid population’s reduction occurs through chemical management, but the indiscriminate use of these products can cause environmental impacts and health risks. This study aimed to determine the insecticidal effects of essential oils and plant extracts as an alternative for aphid control management. The experimental design was entirely randomised in a 5x5 factorial scheme with five replications. Essential oils of rosemary, citronella, corn mint, and hydroethanolic extracts of garlic and cinnamon at five concentrations (0, 10, 20, 40, 80 μL.L−1) were used. In the exposure period of 96 h, the cinnamon hydroethanolic extract and the essential oil of corn mint (Mentha arvensis) showed a greater effect on aphid mortality. The other products evaluated showed lower mortalities but with the potential to be effective with dosages above 80 μL.L−1.

Lethal and sublethal effects of Citrus aurantium and Citrus sinensis essential oils and their major component limonene on Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is an insect pest with great socio-economic importance in different agricultural regions worldwide. This species is highly adaptive and polyphagous, feeding on wild and cultivated host plants. Successive pesticide applications, which negatively affect the environment, are mainly used for managing H. armigera. Studies have investigated alternative methods with low environmental and socioeconomic impacts, including using essential oils. Essential oils are secondary plant-derived metabolites with insecticidal activity in different insect pest populations. Thus, the objective of this study was to evaluate the insecticidal activity of essential oils of Citrus aurantium (Linnaeus) (Rutaceae) and Citrus sinensis (Linnaeus) (Rutaceae) as well as their major component limonene on the biology and reproduction of H. armigera. The essential oils were characterized using gas chromatography-mass spectrometry. Further, their toxicity and the effects of their lethal and sublethal concentrations in larvae and on biological and reproductive parameters in adults were evaluated. All treatments exhibited insecticidal activity and lethal and sub-lethal effects on the biology and reproduction of H. armigera. Therefore, these essential oils could be used to control H. armigera.

Insecticidal Activity of Essential Oils and Their Synergistic Effect on Improving the Efficacy of β-Cypermethrin against Blattella germanica.

We screened the contact activity of 32 commercial essential oils (EOs) and their synergistic effect with β-cypermethrin against Blattella germanica. Results showed that the most effective EOs against B. germanica were from Illicium verum, Syzygium aromaticum, and Cinnamomum camphora, with LD50 values of less than 500 μg/insect. The most potent synergistic effects of β-cypermethrin on B. germanica were from Dysphania ambrosioides and Mentha canadensis. Both oils have a co-toxic factor of 133.33. The results of the major compound testing of the EOs showed that trans-anisaldehyde and thymol have the best insecticidal activity against B. germanica, with LD50 values of 141.30 and 138.61 μg/insect, respectively. The compounds with the best synergistic effect on β-cypermethrin were γ-terpinene and linalool at a concentration of 0.5%. The co-toxic factors for γ-terpinene and linalool were 150 and 133.33, respectively, which were similar to the synergistic effect observed with 2% piperonyl butoxide.

Insecticidal activity of essential oils derived from lavender, laurel and peppermint against lesser grain borer, Rhyzopertha dominica (Fabricius, 1792) (Coleoptera: Bostrichidae)

Fumigant effects of the essential oils from Laurus nobilis L., 1753 (Laurales: Lauraceae), Mentha piperita L., 1753 and Lavandula x intermedia Emeric ex Loisel, 1828 (Lamiales: Lamiaceae) were determined using the lesser grain borer [Rhyzopertha dominica (Fabricius, 1792) (Coleoptera: Bostrychidae)], an important pest species of stored grains. The experiments were conducted in the 2021 in the Department of Crop Protection, Faculty of Agriculture, Malatya Turgut Özal University. The experiments were conducted in a controlled-climate chamber at 27 ± 1°C, 50 ± 10% RH and in the dark. The fumigant effects of essential oils were determined at five concentrations (1, 5, 20, 50 and 200 μl/L air) with larva, pupa and adult stages of R. dominica. The highest fumigant effect was with R. dominica larvae was complete mortality with 200 μl/L L. nobilis essential oil and for the adults, 200μl/L of either L. nobilis and M. piperita essential oil also caused complete mortality. However, the complete mortality of pupal stage was not obtained and the highest mortality was 49% with L. nobilis. As a result, it is considered that both L. nobilis and M. piperita essential oils have the potential to be used as effective biofumigants for stored product pests.

Bio-efficacy of Xanthium strumarium L. Essential Oil against Castor Semilooper, Achaea janata L. (Lepidoptera: Noctuidae)

Background: Although use of synthetic insecticides causes excellent control of insect pests, it leads to adverse effects on non-target organisms as well as the environment. The present study determining the chemical composition and insecticidal activities of essential oil extracted from the leaves of rough cocklebur, Xanthium strumarium and its bioefficacy against the castor semilooper, Achaea janata shall show a new dimension in formulating an ecofriendly management strategy towards castor crop. Methods: Xanthium strumarium leaf essential oil was isolated through hydro-distillation method using Clevenger apparatus and the chemical composition was analysed using GC-MS. The ovicidal and insecticidal activity of the essential oil was determined by dipping and topical application methods, respectively. Larval feeding deterrence and growth inhibitory properties of the essential oil was evaluated through the diet incorporation method. Result: GC-MS analysis of the X. strumarium essential oil revealed the presence of 14 chemical compounds, of which the majority are the terpenes (94.48%). The LC50 values in terms of ovicidal and insecticidal activities were recorded to be 69.70 µL/mL and 0.30 µL/larvae, respectively. The fifty per cent larval feeding deterrence (DC50) and growth inhibitory properties (EC50) were recorded to be 1.88 µl/cm² and 213.94 µL/mL, respectively.

Chemical composition, antifungal, antibacterial, and insecticidal activity of Echinophora chrysantha essential oil

This study presents an investigation of the chemical composition and biological activities of the essential oil (EO) extracted from aerial parts of Echinophora chrysantha (EC). Gas chromatography-mass spectrometry (GC-MS) analysis revealed the presence of twenty-two components, representing 97.5% of the total oil. Major constituents were determined as α-phellandrene (55.74%), β-phellandrene (17.41%), and p-cymene (8.95%). The EO was screened for antimicrobial and antifungal activity against a panel of bacteria and fungi using a broth micro-dilution and fumigant activity assay, respectively. EO sample exhibited better activity against Listeria monocytogenes, Staphylococcus aureus Enterococcus faecium with 31.25, 31.25, and 62.5 μg/mL MIC values. EOs showed moderate mycelium growth inhibitory activity against Phytophthora infestans (32.9±1.9%), Verticillium dahliae (42.3±1.8%), and Fusarium oxysporum f. sp. lycopersici (53.0±2.9%) at 8 μL/petri concentration. The insecticidal activity of EO was also evaluated against two insects (Rhyzopertha dominica and Tribolium confusum) showing moderate activity with mortality rates of 25.8±0.6% and 37.9±1.2% at a 5% (v/v) concentration. Literature search has not revealed any previous work on the antimicrobial, antifungal, and insecticidal activities of the EO from E. chrysantha. In conclusion, this is the first report describing the biological activities of this plant EOs. Additionally, these findings highlight the practical implications of the utilizing essential oil of EC as a potential natural remedy against a spectrum of microbial threats in both pharmaceutical and food preservation applications.

Toxicity of Essential Oil from Plectranthus amboinicus (Lamiales: Lamiaceae) against Sitophilus zeamais (Coleoptera: Curculionidae)1

Abstract Maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), is a major insect pest of stored grain products, causing extensive damage to both grain quantity and quality. The application of synthetic insecticides to control this insect has a negative impact on human health and the environment. Essential oils derived from natural plants are recognized as user- and environmentally friendly alternatives. The use of essential oils from Lamiaceae, which exhibit toxic properties through contact, fumigation, and repellency, provides another option for protecting stored products from various insect pests. The aim of this research was to study the chemical constituents and insecticidal activity of essential oil extracted from the leaves of Indian borage, Plectranthus amboinicus (Lour.) (Lamiales: Lamiaceae), against S. zeamais adults.The chemical composition of the essential oil was analyzed using gas chromatography–mass spectrometry, and the insecticidal activity against adult maize weevils was investigated in the laboratory. The experimental plan followed a completely randomized design with five replications of seven treatments or concentrations of the essential oil: 0, 0.5, 1, 1.5, 2, 2.5, and 3 µl/ml air. The results revealed that the essential oil from the leaves of P. amboinicus contained 23 chemical constituents (97.51%). Thymol (49.96%) was identified as the main compound followed by caryophyllene, trans-α-bergamotene, 3-methyl-4-isopropylphenol, γ-terpinene, p-cymene, caryophyllene oxide, humulene, 4-hydroxy-2-methylacetophenone, 2-hydroxy-2-phenylbutyramide, (2-oxazolidinylidene)malononitrile, hexestrol, terpinen-4-ol, 1-octen-3-ol, (1R,7S,E)-7-isopropyl-4,10-dimethylenecyclodec-5-enol, α-bisabolene, isoaromadendrene epoxide, α-farnesene, 4-carene, α-muurolene, 3-hexen-1-ol, ledene oxide-(II), and α-myrcene, respectively. The fumigation toxicity (median lethal concentration) to maize weevil adults at 48 h was 292.53 µl/ml air. The essential oil from the leaves of P. amboinicus, when applied at a concentration of 2 µl/ml air for 144 and 168 h, resulted in adult maize weevil mortality exceeding 90%. The highest concentration tested (3 µl/ml air) led to exceptionally high mortality rates, with 99–100% of the maize weevils succumbing to the treatment. These findings demonstrate that essential oil from P. amboinicus leaves holds promise as a fumigation insecticide for reducing the population of maize weevils, a significant pest in stored products.

Three Togolese aromatic plants' essential oils diurnal variations and their insecticidal activities against the dengue vector Aedesaegypti

The present reported work deals with the ability of Togolese plants’ essential oils (EOs) to act as repellents for Aedes aegypti mosquitoes in order to use them as personal protective requirements or actions against mosquito bites and therefore to drastically reduce the risk of contracting dengue or yellow fever. EOs studied here were extracted from dry leaves of Ageratum conyzoides L., Eucalyptus citriodora Hook, and Lantana camara Linn, three plants that were collected at different daytimes (7 a.m., 1 p.m., and 7 p.m.) at various locations in Togo. Using a Clevenger-type device, EOs were obtained by the hydrodistillation method (Clevenger, 1928). The physical parameters of the EOs such as density, refractive index, rotatory power, and organoleptic properties were determined. Then, the characterization of EOs using gas chromatography equipped with a flame ionization detector (GC/FID) and gas chromatography coupled to mass spectrometry (GC/MS) was conducted. Chemical analyses showed the presence of several main compounds from EO samples of the three plants. The major compounds were characterized and identified as: (i) precocene I (67.7, 70.6, and 66.9%) and β-caryophyllene (17.4, 12.1, and 16.5%) for the EO of A. conyzoïdes; (ii) citronellal (63.3, 67.2, and 75.4%) and citronellol (24.5, 21.4, and 14.3%) for E. citriodora and (iii) β-caryophyllene (15.3, 11.7, and 12.4%), sabinene (28.4, 35, and 33.3%) and eucalyptol (11.5, 14.1, and 15.6%) for L. camara at 7 a.m., 1 p.m., and 7 p.m., respectively. The yield and the chemical composition of the oils vary according to harvesting time and sunlight.The insecticidal activity of EOs was evaluated following the CDC bottle method on Aedes aegypti females. All the EOs tested on the female adults of Aedes aegypti showed significant insecticidal activity. The EO of A. conyzoïdes at 1 p.m. and 7 p.m. resulted in 100% mortality after 8 min of exposure time at the lowest concentration (0.0025%). At the same concentration for the EO of E. citriodora, the mortality rates were 83%, 38.8%, and 30.80% at 7 a.m., 1 p.m., and 7 p.m., respectively for an exposure time of 8 min. The EO extracted from the leaves of L. camara harvested at 7 a.m. was effective after an exposure time of 15 min for a concentration of 0.02%. For the same concentration, the mortality rates of the EO of L. camara harvested at 1 p.m. and 7 p.m., after 8 min were 62.9% and 52%, respectively.From these interesting results reported for the first time in Togo, EOs from leaves of three Togolese plants harvested at different times of the day appear to be a valuable alternative for mosquito vector control in Togo or abroad countries in which dengue and yellow fever constitute a terrible scourge.

Acaricidal and insecticidal activity of essential oils obtained from the aerial parts of three Mexican Bursera species

In search of new sustainable biopesticides, we determined the phytochemical profiles, acaricidal and insecticidal properties of EOs distilled from the aerial parts of three Mexican Bursera species. Results were obtained by GC–MS analysis and three different bioassays, indicating that the EO of Bursera glabrifolia exhibited high relative abundancies of α-pinene, β-myrcene, and α-phellandrene, as well as promising pesticidal activity against Spodoptera littoralis larvae (LD50,90 = 32.4, 107.2 µg/larva), and Musca domestica (LD50,90 = 23.2, 103.2, and 13.5, 77.4 µg/female or male adult, respectively) and Tetranychus urticae adults (LD50,90 = 7.4, 30.3 µg/cm2). The Bursera lancifolia and Bursera linanoe samples contained mainly D-limonene or linalyl acetate and linalool, respectively, and showed generally less potent pesticidal properties (S. littoralis larva, LD50,90 = 45.4, 154.4 and 52.2, 158.7 µg/larva, respectively; female M. domestica adult, LD50,90 = 69.2, 210.9 and 45.1, 243.8 µg/female adult, respectively; T. urticae adults, LD50,90 = 20.7, 90.5 and 17.5, 71.4 µg/cm2, respectively). However, the EO of B. linanoe exhibited an especially pronounced activity against male M. domestica adults (LD50,90 = 10.6, 77.2 µg/male adult). Our findings prove the pesticidal potential of Mexican Bursera species in the context of integrated pest management (IPM) and highlight the importance of conducting further research to elucidate both the active principles and possibly existing synergistic effects.

Insecticidal activity of essential oil from leaves of Eugenia stipitata McVaugh against Aedes aegypti

Aedes aegypti, a mosquito, is responsible for the spread of many diseases, including dengue, zika, and chikungunya. However, due to this mosquito's developed resistance to conventional pesticides, effectively controlling it has proven to be challenging. This study aimed to evaluate the insecticidal potential of the essential oil from the leaves of Eugenia stipitata against Ae. aegypti, offering a natural and sustainable alternative for mosquito control. Tests were conducted using third-stage larvae to evaluate larvicidal activity and pupae collected up to 14 h after transformation to investigate pupicidal activity. Throughout the bioassays, the organisms were exposed to various essential oil concentrations. The findings demonstrated that the essential oil of E. stipitata exhibited larvicidal action, resulting in 100% larval mortality after 24 h and an LC50 value of 0.34 mg/mL. The effectiveness of essential oil as a pupicidal agent was also demonstrated by its LC50 value of 2.33 mg/mL and 100% larval mortality in 24 h. It can be concluded that the essential oil of E. stipitata holds promise as a natural pest control agent. Its use may reduce the reliance on conventional chemical pesticides, providing a more sustainable and effective strategy to combat diseases spread by mosquitoes.

Chemistry and Insecticidal Activity of Essential Oils against Trogoderma granarium Larvae

Chemistry and Insecticidal Activity of Essential Oils against Trogoderma granarium Larvae

Insecticidal activities of essential oil of Ocimun gratissimun in composite of modified saponins-clay montmorillonite and mango seed starch bioplastic

Insecticidal activities of essential oil of Ocimun gratissimun in composite of modified saponins-clay montmorillonite and mango seed starch bioplastic

Fumigant Contact and Repellent Actions of Essential Oils of Leaves, Fruits and Stems from Melicope pteleifolia Against Three Pests

Storage pests influence food production and conservation worldwide. The common control measures for these pests involve the use of synthetic pesticides, but these pesticides are harmful to the environment and human health. Thus, biological insecticides can substitute or reduce dependence on synthetic insecticides. This work aimed to study the insecticidal activities of essential oils (EOs) from leaves, fruits and stems of Melicope pteleifolia and their main compound against three kinds of pests, Tribolium castaneum, Lasioderma serricorne and Liposcelis bostrychophila. The Gas Chromatography - Mass Spectrometry (GC-MS) detection showed that β-cis-ocimene was the major compound in EOs from leaves and fruits of M. pteleifolia (26.96, and 65.99%, respectively). The main compound of stems EO is origanene (77.00%). In the fumigation test, EO of fruits and β-cis-ocimene were toxic to L. serricorne, and β-cis-ocimene was toxic to T. castaneum. The EOs and β-cis-ocimene had significant contact toxicity and repellent effect on these three species of pests. The results indicated that M. pteleifolia EOs are potential biological insecticides for controlling storage pests.

Insecticidal activity of essential oils from American native plants against Aedes aegypti (Diptera: Culicidae): an introduction to their possible mechanism of action

Searching for new bioactive molecules to design insecticides is a complex process since pesticides should be highly selective, active against the vector, and bio-safe for humans. Aiming to find natural compounds for mosquito control, we evaluated the insecticidal activity of essential oils (EOs) from 20 American native plants against Aedes aegypti larvae using bioassay, biochemical, and in silico analyses. The highest larvicide activity was exhibited by EOs from Steiractinia aspera (LC50 = 42.4 µg/mL), Turnera diffusa (LC50 = 70.9 µg/mL), Piper aduncum (LC50 = 55.8 µg/mL), Lippia origanoides (chemotype thymol/carvacrol) (LC50 = 61.9 µg/mL), L. origanoides (chemotype carvacrol/thymol) (LC50 = 59.8 µg/mL), Hyptis dilatata (LC50 = 61.1 µg/mL), Elaphandra quinquenervis (LC50 = 61.1 µg/mL), and Calycolpus moritzianus (LC50 = 73.29 µg/mL) after 24 h. This biological activity may be related to the disruption of the electron transport chain through the mitochondrial protein complexes. We hypothesized that the observed EOs' effect is due to their major components, where computational approaches such as homology modeling and molecular docking may suggest the possible binding pose of secondary metabolites that inhibit the mitochondrial enzymes and acetylcholinesterase activity (AChE). Our results provided insights into the possible mechanism of action of EOs and their major compounds for new insecticide designs targeting the mitochondria and AChE activity in A. aegypti for effective and safe insecticide.

Chemical Constituents, Antioxidant, Antimicrobial and Insecticidal Activities of the Essential Oils Extracted from Thymus guyonii de Noé and Thymus algeriensis Boiss. et Reut.

This study was designed to determine the chemical composition, antioxidant, antimicrobial and insecticidal activities of essential oils of Thymus guyonii and Thymus algeriensis. The essential oils (EOs) were isolated by hydrodistillation and analyzed by GC and GC-MS. The leading components of the oils were p-cymene (15.8%), γ-terpinene (15.3%), thymol methyl ether (15.7%) and thymol (19.1%) for T. guyonii and α-pinene (4.4%), camphor (4.6%), bornyl acetate (5.4%) and terpinenyl actate (28.1%) for T. algeriensis. The antioxidant activity was evaluated in terms of scavenging of free radicals DPPH● and ABTS●+. The essential oil of T. guyonii was the most efficient in inhibiting free radicals but less active compared to synthetic antioxidants (Trolox and BHT). Also, T. guyonii essential oil showed the highest effectiveness against the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae) as well as against five microorganisms, two gram-positive (Staphylococcus aureus and Bacillus subtilis), one gram-negative (Escherichia coli), one yeast (Candida albicans) and one fungus (Aspergillus brasiliensis). The results suggest that the EO of T. guyonii could be considered in pharmaceutical and food fields as well as for preservation of stored products from S. oryzae damage.

Insecticidal Activity of Essential Oil from Seeds of Foeniculum vulgare (Apiales: Apiaceae) Against Sitophilus zeamais (Coleoptera: Curculionidae) and Its Effects on Crop Seed Germination

Abstract Many aromatic herbs in the family Apiaceae produce essential oils that are used on an industrial scale for medicinal, cosmetic, and food purposes. Essential oils from plants that show insecticidal activity can be substituted for synthetic insecticides to reduce environmental pollution or harmful toxicity to humans. Insecticidal activity of essential oil from seeds of coriander, Foeniculum vulgare Miller (Apiales: Apiaceae), on maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), and its effects on seed germination of three major economic crops were investigated. Essential oil from F. vulgare seeds was analyzed by gas chromatography–mass spectrometry and found to contain 25 components, with anethole (43.78%) as the main constituent. Other basic compounds were estragole (28.33%), fenchone (16.68%), d-limonene (2.62%), alpha-pinene (1.84%), and p-cymene (1.28%). Foeniculum vulgare essential oil was toxic to maize weevil when used as a fumigant with a median lethal concentration at 48 h of 10.42 µL/L air. A concentration of 64 µL/L air was most effective, killing 100% of maize weevil within 24 h. The repellent effect on maize weevil increased to 75% at 24 h at a concentration of 16 µL/L air. Rice (Oryza sativa L.) and sorghum (Sorghum bicolor [L.] Moench) seeds fumigated with 32 µL/L air of F. vulgare essential oil exhibited a slight decrease in germination rate (germination >90%). Our results indicate that essential oil from F. vulgare seeds have potential for application in the management of maize weevil in stored products.

Insecticidal Activity of Essential Oils against Mealybug Pests (Hemiptera: Pseudococcidae): A Systematic Review and Meta-Analysis

Most mealybugs of the Pseudococcidae family are important pests of agriculture and ornamental gardens. Our aim was to perform a review and meta-analysis on 14 published scientific articles on the insecticidal activity of essential oils (EOs) against mealybug species of the Pseudococcidae family. Data on (1) species, genus, families, and plant parts from which the EO was extracted; (2) the main compounds of each EO; (3) the highest and lowest concentrations tested; and (4) the application method used for the toxicological studies was collected from each study. The metafor package (R software) was used to perform a three-level random effects meta-analysis. The families Lamiaceae, Rutaceae, Myrtaceae, Zingiberaceae and Euphorbiaceae and the genera Citrus, Cymbopogon, Syzygium, Cinnamomum and Jatropha were the most used among the studies. According to the results from the meta-analyses, 13 out of 24 genera analyzed were effective against mealybugs. All methods were effective, but fumigation and indirect contact were the most frequently used methodologies. The results obtained from the present review and meta-analysis could be used for the potential development of natural biopesticide formulations against mealybugs belonging to the Pseudococcidae family.

Chemical Composition and Evaluation of Antifungal and Insecticidal Activities of Essential Oils Extracted from Jambosa caryophyllus (Thunb.) Nied: Clove Buds.

Jambosa caryophyllus has been used in traditional phytotherapy as a treatment against infections. In the present work, essential oils extracted from clove buds (Jambosa caryophyllus ) (EO-JC) were investigated for their composition, antifungal, and insecticidal properties. Extraction of EO-JC was performed by use of hydrodistillation using a Clevenger-type apparatus, and the EOs were analyzed by gas chromatography coupled with mass spectrometry (GC-MS). Antifungal activity of EO-JC was evaluated by the use of solid-state diffusion (disc method) and microdilution to determine the minimum inhibitory concentration (MIC), against three strains of fungus, Aspergillus niger, Aspergillus flavus, and Fusarium oxysporum. Insecticidal activity of EO-JC against the cowpea weevil, Callosobruchus maculatus, was determined to assess utility of EO-JC to control this pest. Several exposures including inhalation and contact were used to determine lethality, as well as the repulsion test was conducted at concentrations of 4, 8, 16, and 32 μL EO-JC. Characterization of EO-JC by GC/MS revealed 34 compounds accounting for 99.98% of the mass of the extract. The predominant compound was eugenol (26.80%) followed by β-caryophyllene (16.03%) and eugenyl acetate (5.83%). The antifungal activity of EO-JC on solid media exhibited inhibitions in the range of 49% to 87%, and MIC was between 3.125 and 7.80 μg EO-JC/mL. Insecticidal activity, as determined by the use of the inhalation test, and expressed as the LD50 and LD95 after 96 hours of exposure was 2.32 and 21.92 μL/L air, respectively. In the contact test, a 96-hour exposure resulted in LD50 and LD95 of 5.51 and 11.05 μL/L of air, respectively. EO-JC exhibited insecticidal activity against fungi and pest chickpea weevil.

Insecticidal Activity of Four Essential Oils Extracted from Chilean Patagonian Plants as Potential Organic Pesticides.

Patagonia is a geographical area characterized by a wide plant biodiversity. Several native plant species are traditionally used in medicine by the local population and demonstrated to be sources of biologically active compounds. Due to the massive need for green and sustainable pesticides, this study was conducted to evaluate the insecticidal activity of essential oils (EOs) from understudied plants growing in this propitious area. Ciprés (Pilgerodendron uviferum), tepa (Laureliopsis philippiana), canelo (Drimys winteri), and paramela (Adesmia boronioides) EOs were extracted through steam distillation, and their compositions were analyzed through GC–MS analysis. EO contact toxicity against Musca domestica L., Spodoptera littoralis (Boisd.), and Culex quinquefasciatus Say was then evaluated. As a general trend, EOs performed better on housefly males over females. Ciprés EO showed the highest insecticidal efficacy. The LD50(90) values were 68.6 (183.7) and 11.3 (75.1) µg adult−1 on housefly females and males, respectively. All EOs were effective against S. littoralis larvae; LD50 values were 33.2–66.7 µg larva−1, and tepa EO was the most effective in terms of LD90 (i.e., <100 µg larva−1). Canelo, tepa, and paramela EOs were highly effective on C. quinquefasciatus larvae, with LC50 values < 100 µL L−1. Again, tepa EO achieved LD90 < 100 µL L−1. This EO was characterized by safrole (43.1%), linalool (27.9%), and methyl eugenol (6.9%) as major constituents. Overall, Patagonian native plant EOs can represent a valid resource for local stakeholders, to develop effective insecticides for pest and vector management, pending a proper focus on their formulation and nontarget effects.

When Scent Becomes a Weapon—Plant Essential Oils as Potent Bioinsecticides

Crop protection still mostly relies on synthetic pesticides for crop pest control. However, the rationale for their continued use is shaded by the revealed adverse effects, such as relatively long environmental persistence that leads to water and soil contamination and retention of residues in food that brings high risks to human and animal health. As part of integrated pest management, biopesticides may provide crop protection, being eco-friendly and safe for humans and non-target organisms. Essential oils, complex mixtures of low-molecular-weight, highly volatile compounds, have been highlighted as major candidates for plant-derived bioinsecticides that are up to the sustainable biological standard. In this review, we screened the insecticidal activity of essential oils or their purified compounds, with focus given to their modes of action, along with the analyzed advantages and problems associated with their wider usage as plant-derived insecticides in agriculture.