Recently, spices have attracted the attention of scientists and agrochemical companies for their potential as insecticidal and acaricidal agents, and even as repellents to replace synthetic compounds that are labeled with detrimental impacts on environment and human and animal health. In this framework, the aim of this study was to evaluate the insecticidal potential of the essential oils (EOs) obtained from three Cameroonian aromatic plants, namely Monodora myristica (Gaertn.) Dunal, Xylopia aethiopica (Dunal) A. Rich., and Aframomum citratum (J. Pereira) K. Schum. They were produced by hydrodistillation, with yields of 3.84, 4.89, and 0.85%, respectively. The chemical composition was evaluated by GC-MS analysis. The EOs and their major constituents (i.e., geraniol, sabinene, α-pinene, p-cymene, α-phellandrene, and β-pinene) were tested against the polyphagous moth pest, i.e., Spodoptera littoralis (Boisd.), the common housefly, Musca domestica L., and the filariasis and arbovirus mosquito vector, Culex quinquefasciatus Say. Our results showed that M. myristica and X. aethiopica EOs were the most effective against M. domestica adults, being effective on both males (22.1 µg adult-1) and females (LD50: 29.1 µg adult-1). The M. myristica EO and geraniol showed the highest toxicity on S. littoralis, with LD50(90) values of 29.3 (123.5) and 25.3 (83.2) µg larva-1, respectively. Last, the EOs from M. myristica and X. aethiopica, as well as the major constituents p-cymene and α-phellandrene, were the most toxic against C. quinquefasciatus larvae. The selected EOs may potentially lead to the production of cheap and effective botanical insecticides for African smallholders, although the development of effective formulations, a safety evaluation, and an in-depth study of their efficacy on different insect species are needed.

• Keywords
• Aframomum citratum, Culex quinquefasciatus, Culicidae, Monodora myristica, Musca domestica, Muscidae, Noctuidae, Spodoptera littoralis, Xylopia aethiopica, geraniol, p-cymene, sabinene, α-phellandrene, α-pinene, β-pinene,
• Publication type
• Journal Article MeSH

The gypsy moth (Lymantria dispar L. (Lepidoptera: Erebidae)) is a serious pest of hardwood forests. In the search for an environmentally safe means of its control, we assessed the impact of different concentrations of essential oils (EOs) from the seeds of three Apiaceae plants (anise Pimpinella anisum, dill Anethum graveolens, and fennel Foeniculum vulgare) on behavior, mortality, molting and nutritional physiology of gypsy moth larvae (GML). EOs efficacy was compared with commercial insecticide NeemAzal®-T/S (neem). The main compounds in the Eos were trans-anethole in anise; carvone, limonene, and α-phellandrene in dill; and trans-anethole and fenchone in fennel seed. At 1% EOs concentration, anise and fennel were better antifeedants and all three EOs were more toxic than neem. Neem was superior in delaying 2nd to 3rd larval molting. In the 4th instar, 0.5%, anise and fennel EOs decreased relative consumption rate more than neem, whereas all three EOs were more effective in reducing growth rate, approximate digestibility and efficiency of conversion of food into body mass leading to higher metabolic costs to GML. Decrease in consumption and metabolic parameters compared to control GML confirmed that adverse effects of the EOs stem from both pre- and post-ingestive mechanisms. The results indicate the potential of three EOs to be used for gypsy moth control.

• Keywords
• botanical insecticide, deterrence coefficient, digestive toxicity, insect pest management, nutritional indices,
• Publication type
• Journal Article MeSH

The western flower thrips (Frankliniella occidentalis Perg.) is one of the most economically important insect pests of greenhouse plants. Plant protection against this pest is based predominantly on synthetic insecticides; however, this form of protection poses problems in terms of thrip resistance to the active substances, along with health risks associated with insecticide residues on the treated plants. Therefore, new active substances need to be sought. Essential oils could be a new, appropriate, and safe alternative for greenhouse culture protection. As greenhouses are enclosed areas, fumigation application of EOs is possible. This paper presents acute toxicity results for 15 commercial EOs applied by fumigation, as well as the effect of sublethal concentrations on fertility of F. occidentalis females. The most efficient EOs were obtained from Mentha pulegium and Thymus mastichina, with LC50(90) estimated as 3.1(3.8) and 3.6 (4.6) mg L-1 air, respectively. As found for the very first time, sublethal concentrations of EOs could result in a significant reduction in the fertility of surviving T. occidentalis females. Among the tested EOs, the EO from Nepeta cataria provided the highest inhibition of fertility, with EC50(90) estimated as 0.18 (0.36) mg L-1 air. Chemical composition of the most efficient EOs and possible applications of the results in practice are discussed. In conclusion, in light of the newly determined facts, EOs can be recommended as active substances for botanical insecticides to be applied against Thysanopteran pests by fumigation.

• Keywords
• Botanical insecticides, Essential oils, Fumigant toxicity, Greenhouse, Sublethal effect, Thrips,
• MeSH
• Fertility drug effects   MeSH
• Insecticides pharmacology   MeSH
• Mentha pulegium chemistry   MeSH
• Oils, Volatile chemistry   pharmacology   MeSH
• Thymus Plant chemistry   MeSH
• Thysanoptera drug effects   physiology   MeSH
• Fumigation MeSH
• Animals MeSH
• Check Tag
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Insecticides MeSH
• Oils, Volatile MeSH

Developing effective and eco-friendly antiparasitic drugs and insecticides is an issue of high importance nowadays. In this study, we evaluated the anthelminthic and insecticidal potential of the leaf essential oil obtained from Origanum syriacum against the L3 larvae of the parasitic nematode Anisakis simplex and larvae and adults of the mosquito Culex quinquefasciatus. Tests on A. simplex were performed by standard larvicidal and penetration assays, while mosquito toxicity was assessed relying on larvicidal, tarsal contact, and fumigation tests. To shed light on the possible mode of action, we analyzed the oil impact as acetylcholinesterase (AChE) inhibitor. This oil was particularly active on L3 larvae of A. simplex, showing a LC50 of 0.087 and 0.067 mg mL-1 after 24 and 48 h treatment, respectively. O. syriacum essential oil was highly effective on both larvae and adults of C. quinquefasciatus, showing LC50 values of 32.4 mg L-1 and 28.1 µg cm-2, respectively. Its main constituent, carvacrol, achieved larvicidal LC50(90) of 29.5 and 39.2 mg L-1, while contact toxicity assays on adults had an LC50(90) of 25.5 and 35.8 µg cm-2, respectively. In fumigation assays, the LC50 was 12.1 µL L-1 after 1 h and decreased to 1.3 µL L-1 in 24 h of exposure. Similarly, the fumigation LC50 of carvacrol was 8.2 µL L-1 after 1 h of exposure, strongly decreasing to 0.8 µL L-1 after 24 h of exposure. These results support the folk usage of Lebanese oregano as an antiparasitic agent, providing new insights about its utilization for developing new effective and eco-friendly nematocidal and insecticidal products.

• Keywords
• anisakiasis, contact toxicity, enzyme inhibition, fumigation toxicity, larvicide, mosquito control, penetration assay,
• MeSH
• Anisakis drug effects   MeSH
• Cholinesterase Inhibitors chemistry   pharmacology   MeSH
• Culex drug effects   MeSH
• Cymenes pharmacology   MeSH
• Origanum chemistry   MeSH
• Mosquito Vectors drug effects   MeSH
• Larva drug effects   MeSH
• Plant Leaves chemistry   MeSH
• Oils, Volatile chemistry   pharmacology   MeSH
• Plant Oils chemistry   pharmacology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• carvacrol MeSH Browser
• Cholinesterase Inhibitors MeSH
• Cymenes MeSH
• Oils, Volatile MeSH
• Plant Oils MeSH

Every year Chile exports about 2000 tons of boldo folium (Peumus boldus), which is used around the world as a traditional herbal medicinal product (THMP), mostly to relieve gastrointestinal disorders. This biomass may be a resource for the agrochemical industry to manufacture botanical insecticides. In this regard, the insecticidal potential of boldo has been poorly investigated. In the present work, hydrodistillation of a commercial boldo folium gave 1.5% (w/w) of a yellowish essential oil (boldo essential oil, BEO) containing 1,8-cineole (20.7%), p-cymene (18.5%), limonene (9.1%), ascaridole (9.1%) and β-phellandrene (6.4%) as the main constituents, as determined by gas chromatography-mass spectrometry (GC-MS). NMR analysis allowed us to determine that ascaridole was mainly represented by the cis-isomer. BEO was toxic to larvae of the filariasis vector Culex quinquefasciatus and adults of the housefly Musca domestica, showing LC50/LD50 values of 67.9 mg·L-1 and 98.5 µg·adult-1, respectively. On the other hand, lower insecticidal activity was observed against larvae of the moth pest Spodoptera littoralis (LD50 of 268.9 µg·larva-1). It is worth noting that, when tested at LC90 concentration, BEO was significantly less toxic to aquatic microcrustacean Daphnia magna than the conventional insecticide α-cypermethrin. Finally, in the attempt to explore the BEO mode of action, we tested it for acetylcholinesterase (AChE) inhibitory properties using the Ellman method, obtaining negligible effects (IC50 = 0.45 mg·mL-1). Taken together, these results gave new insights into the potential of BEO as a future ingredient of botanical insecticides.

• Keywords
• Culex quinquefasciatus, Musca domestica, aquatic ecotoxicology, ascaridole, insecticide,
• MeSH
• Culex drug effects   MeSH
• Cyclohexenes chemistry   MeSH
• Cymenes MeSH
• Daphnia drug effects   MeSH
• Insecticides chemistry   pharmacology   MeSH
• Mosquito Vectors drug effects   MeSH
• Larva drug effects   MeSH
• Lethal Dose 50 MeSH
• Humans MeSH
• Cyclohexane Monoterpenes MeSH
• Monoterpenes chemistry   MeSH
• Houseflies drug effects   MeSH
• Moths drug effects   MeSH
• Oils, Volatile chemistry   pharmacology   MeSH
• Peroxides chemistry   MeSH
• Peumus chemistry   MeSH
• Gas Chromatography-Mass Spectrometry MeSH
• Pyrethrins chemistry   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• 4-cymene MeSH Browser
• ascaridole MeSH Browser
• beta-phellandrene MeSH Browser
• Cyclohexenes MeSH
• Cymenes MeSH
• cypermethrin MeSH Browser
• Insecticides MeSH
• Cyclohexane Monoterpenes MeSH
• Monoterpenes MeSH
• Oils, Volatile MeSH
• Peroxides MeSH
• Pyrethrins MeSH