scholarly journals Rapid Immobilization of Adult Aedes aegypti Caused By Plant Essential Oils At Sublethal Concentrations

2018 ◽  
Vol 34 (3) ◽  
pp. 210-216 ◽  
Author(s):  
Edmund J. Norris ◽  
Maria Archevald-Cansobre ◽  
Aaron D. Gross ◽  
Lyric C. Bartholomay ◽  
Joel R. Coats
Keyword(s):  
Aedes Aegypti ◽  
Essential Oils ◽  
Adult Female ◽  
Insect Pests ◽  
Plant Essential Oils ◽  
Knockdown Effect ◽  
Test Population ◽  
Insect Populations ◽  
Delayed Mortality ◽  
Sublethal Concentrations

ABSTRACT Many synthetic insecticides cause immobilization in insect pests after they are exposed. This immobilization or knockdown is an important feature of intoxication that contributes to the abatement of pest insect populations, while preventing vectors of disease from biting and spreading pathogenic organisms to susceptible individuals. We have previously demonstrated that certain plant essential oils rapidly immobilize adult female mosquitoes that have been exposed via topical application. To further characterize this effect, adult female Aedes aegypti were exposed to multiple concentrations of 32 commercially available plant essential oils, and immobilization at 1 h after exposure was recorded. The dose required to produce the 1-h knockdown effect in 50% of the test population (KD50) was calculated and compared with concentrations of each plant essential oil that caused mortality at 24 h. In the current study, multiple plant essential oils caused high percentage knockdown at 1 h at lower concentrations than concentrations that caused mortality at 24 h. Moreover, delayed mortality was observed in mosquitoes that were exposed to various concentrations of the 2 plant essential oils that produced significant knockdown at 1 h. These observations demonstrate an important characteristic of many plant essential oils and represent a novel means for which these oils may be incorporated into future insecticidal formulations.

scholarly journals Efficacy of natural oils against the biological activity on Callosobruchus maculatus and Callosobruchus chinensis (Coleoptera: Tenebrionidae)

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Magda Mahmoud Amin Sabbour
Keyword(s):  
Essential Oils ◽  
Callosobruchus Maculatus ◽  
Insect Pests ◽  
Adult Emergence ◽  
Effective Dosage ◽  
Callosobruchus Chinensis ◽  
Storage Pests ◽  
Plant Essential Oils ◽  
Natural Oils ◽  
Coleoptera Tenebrionidae

Abstract Background Callosobruchus maculatus and C. chinensis (Coleoptera: Tenebrionidae) are dangerous insects to stored grains. They are controlled by chemical insecticides, which cause a lot of harmful diseases and pollute the environment. Essential oils are a new trend for controlling of storage pests. Methods The nano-encapsulation process was carried out by polymerization technology. The tested nano-oils were experimented at tested concentration (0.5%) for their insecticidal activities against the third-instar larvae of tested insects. After 7 days of exposure, accumulative mortality percentages were calculated in the treated and untreated control. Also, the tested nano-oils were sprayed to the foam granules and were mixed with 2 g foam/100 g cow pea for testing the oviposition inhibitory effects of the tested oils. Additionally, the experiment was designed to test the latent effect of the tested oils against C. maculatus and C. chinensis on foam as surface protectant after 90-day intervals. Results After 7 days of treatments, the accumulations of C. maculatus were 61.2, 42.0, 46.6, and 35.5% after being treated with rosemary, catnip, garlic, and citronella oil, respectively, as compared to 0.3% in the control. When C. chinensis were treated with corresponding oils, the accumulations obtained 68.9, 44.1, 49.9, and 37.9% as compared to 0.1% in the control. When both the target insect pests, C. maculatus and C. chinensis, were treated with the tested nano-oils, results showed that the accumulations of C. maculatus recorded 82.2, 55.8, 66.3, and 46.3% when treated with nano-rosemary, nano-anis, nano-garlic, and nano-citronella as compared to 0.1 in the control. When the corresponding nano-oils were applied against C. chinensis, the accumulations obtained 89.7, 42.8, 70.9, and 48.9% as compared to 0.1% in the control. When the tested oils and their nano were tested against C. maculatus life cycle, the number of eggs laid/female were significantly decreased to 6.4 ± 9.89 eggs/female after nano-rosemary treatments as compared to 299.9 ± 9299 eggs/female in the control. The adult emergence decreased to 1% after nano-rosemary treatments as compared to 100% in the control. The malformations of the insect significantly increased after nano-rosemary and nano-anis to 100% as compared to 0% in the control. The same results obtained when C. chinensis were treated with different tested oils. The number of eggs C. chinensis laid/female was 8.3 ± 1.0 eggs/female as compared to 298.9 ± 7.89 eggs/female in the control. Conclusion This work research indicate that some essential oils might be useful for managing C. maculatus and C. chinensis in enclosed spaces because of their fumigant harmful action. Plant essential oils and their active ingredient have potentially high bioactivity against a range of the target insect pests. Furthermore, they are highly selective to C. maculatus and C. chinensis. Incorporation of essential oils into a controlled release nano-formulation prevents rapid vaporization and degradation, increases constancy, and preserves the lower effective dosage/application. Treated foam with nano-rosemary and nano-garlic oils and covering gunny bags provided many efficient effects against tested insects.

scholarly journals Plant essential oils synergize various pyrethroid insecticides and antagonize malathion in Aedes aegypti

2019 ◽  
Vol 33 (4) ◽  
pp. 453-466 ◽  
Author(s):  
E. J. Norris ◽  
A. D. Gross ◽  
L. C. Bartholomay ◽  
J. R. Coats
Keyword(s):  
Aedes Aegypti ◽  
Essential Oils ◽  
Pyrethroid Insecticides ◽  
Plant Essential Oils

Ovicidal, larvicidal, and behavioural effects of some plant essential oils on diamondback moth (Lepidoptera: Plutellidae)

2017 ◽  
Vol 149 (5) ◽  
pp. 639-648 ◽  
Author(s):  
Jatinder S. Sangha ◽  
Tess Astatkie ◽  
G. Christopher Cutler
Keyword(s):  
Essential Oils ◽  
Insect Pests ◽  
Low Cost ◽  
Insect Pest ◽  
Diamondback Moth ◽  
Abies Balsamea ◽  
Black Pepper ◽  
Piper Nigrum ◽  
Larval Feeding ◽  
Plant Essential Oils

AbstractAlternatives to synthetic insecticides are desirable for management of diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), an insect pest of global importance. Many essential oils derived from aromatic plants have demonstrated toxicity and behaviour altering effects on insect pests, and are considered low-risk alternatives to synthetic insecticides. We conducted laboratory experiments to determine the biological activity of several low-cost, commercially available essential oils against P. xylostella. Experiments testing ovicidal effects, larvicidal effects, larval feeding deterrence, and adult oviposition deterrence were done with essential oils derived from Artemisia abrotanum Linnaeus (Asteraceae), balsam fir (Abies balsamea Linnaeus (Pinaceae)), black pepper (Piper nigrum Linnaeus (Piperaceae)), eucalyptus (Eucalyptus polybractea (Baker) (Myrtaceae)), garlic (Allium sativum Linnaeus (Amaryllidaceae)), rosewood (a blend of different oil constituents), tansy (Tanacetum vulgare Linnaeus (Asteraceae)), and thyme (Thymus zygis Linnaeus (Lamiaceae)), using concentrations of 1, 2.5, and 5% v/v. Although all essential oils had some level of bioactivity against certain P. xylostella life stages, essential oils from garlic, rosewood, and thyme were most effective overall, demonstrating significant ovicidal and larvicidal activity, as well as deterrent effects on larval feeding and settling behaviour, and adult oviposition. Although variable phytotoxicity was observed with essential oils at 2.5% and 5% v/v concentrations, the results suggest that rosewood, garlic, and thyme essential oils have potential in management of P. xylostella.

scholarly journals Co-Toxicity Factor Analysis Reveals Numerous Plant Essential Oils Are Synergists of Natural Pyrethrins against Aedes aegypti Mosquitoes

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 154
Author(s):  
Edmund J. Norris ◽  
Jeffrey R. Bloomquist
Keyword(s):  
Factor Analysis ◽  
Aedes Aegypti ◽  
Essential Oils ◽  
Pearson Correlation ◽  
Synergistic Activity ◽  
Female Adult ◽  
Plant Essential Oils ◽  
East Indies ◽  
Toxicity Factor ◽  
Control Technologies

With insecticide-resistant mosquito populations becoming an ever-growing concern, new vector control technologies are needed. With the lack of new chemical classes of insecticides to control mosquito populations, the development of novel synergists may improve the performance of available insecticides. We screened a set of 20 plant essential oils alone and in combination with natural pyrethrins against Aedes aegypti (Orlando) female adult mosquitoes to assess their ability to synergize this natural insecticide. A co-toxicity factor analysis was used to identify whether plant oils modulated the toxicity of natural pyrethrins antagonistically, additively, or synergistically. Both knockdown at 1 h and mortality at 24 h were monitored. A majority of oils increased the toxicity of natural pyrethrins, either via an additive or synergistic profile. Many oils produced synergism at 2 µg/insect, whereas others were synergistic only at the higher dose of 10 µg/insect. Amyris, cardamom, cedarwood, and nutmeg East Indies (E.I.) oils were the most active oils for increasing the mortality of natural pyrethrins at 24 h with co-toxicity factors greater than 50 at either or both doses. A number of oils also synergized the 1 h knockdown of natural pyrethrins. Of these, fir needle oil and cypress oils were the most successful at improving the speed-of-action of natural pyrethrins at both doses, with co-toxicity factors of 130 and 62, respectively. To further assess the co-toxicity factor method, we applied selected plant essential oils with variable doses of natural pyrethrins to calculate synergism ratios. Only the oils that produced synergistic co-toxicity factors produced statistically significant synergism ratios. This analysis demonstrated that the degree of co-toxicity factor correlated well with the degree of synergism ratio observed (Pearson correlation coefficient r = 0.94 at 2 µg/insect; r = 0.64 at 10 µg/insect) and that the co-toxicity factor is a useful tool in screening for synergistic activity.

scholarly journals Essential Oil Compositions of Three Invasive Conyza Species Collected in Vietnam and Their Larvicidal Activities against Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4576
Author(s):  
Tran Minh Hoi ◽  
Le Thi Huong ◽  
Hoang Van Chinh ◽  
Dang Viet Hau ◽  
Prabodh Satyal ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Essential Oils ◽  
Culex Quinquefasciatus ◽  
Insect Pests ◽  
Gas Chromatography Mass Spectrometry ◽  
Tropical Regions ◽  
Persistent Problem ◽  
Aerial Parts ◽  
Increasing Demand ◽  
Larvicidal Activities

Mosquito-borne infectious diseases are a persistent problem in tropical regions of the world, including Southeast Asia. Vector control has relied principally on synthetic insecticides, but these have detrimental environmental effects and there is an increasing demand for plant-based agents to control insect pests. Invasive weedy plant species may be able to serve as readily available sources of essential oils, some of which may be useful as larvicidal agents for control of mosquito populations. We hypothesize that members of the genus Conyza (Asteraceae) may produce essential oils that may have mosquito larvicidal properties. The essential oils from the aerial parts of Conyza bonariensis, C. canadensis, and C. sumatrensis were obtained by hydrodistillation, analyzed by gas chromatography–mass spectrometry, and screened for mosquito larvicidal activity against Aedes aegypti, Ae. albopictus and Culex quinquefasciatus. The essential oils of C. canadensis and C. sumatrensis, both rich in limonene (41.5% and 25.5%, respectively), showed notable larvicidal activities against Ae. aegypti (24-h LC50 = 9.80 and 21.7 μg/mL, respectively) and Ae. albopictus (24-h LC50 = 18.0 and 19.1 μg/mL, respectively). These two Conyza species may, therefore, serve as sources for alternative, environmentally-benign larvicidal control agents.

scholarly journals Influence of drying on the chemical composition and bioactivity of Piper aduncum (Piperaceae) essential oil against Aedes aegypti (Diptera: Culicidae)

2021 ◽  
Vol 10 (8) ◽  
pp. e46810817397
Author(s):  
Thais Silva Santos ◽  
Taynara Ellen Sardeiro Vieira ◽  
José Realino de Paula ◽  
Jerônimo Raimundo de Oliveira Neto ◽  
Luiz Carlos da Cunha ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Aedes Aegypti ◽  
Essential Oils ◽  
Insect Pests ◽  
Intraspecific Variability ◽  
High Yield ◽  
Drying Process ◽  
Chemical Evaluation ◽  
High Incidence ◽  
Piper Aduncum

Piper species are producers of essential oils with high yield and promising chemical composition for both perfumery and the pharmaceutical industry. They present bioactivity against pathogens and against insect pests, whether agricultural or medical, such as Aedes aegypti, for example, a vector of arboviruses with a high incidence in tropical and subtropical regions. In this study, an investigation was carried out to elucidate the chemical composition of essential oils from the leaves and inflorescences of Piper aduncum collected in the state of Goiás, Brazil. Evaluating the interference of the drying process on yield, chemical composition and larvicide potential against Ae. aegypti. Leaves and inflorescences of P. aduncum were collected in the rural area of the municipality of Iporá-GO. Fresh and dried samples were processed separately and subjected to hydrodistillation for two hours. The oil obtained was qualitatively evaluated by gas-coupled chromatography and mass spectrometry. Greater yield was observed in samples submitted to the drying process. Oils obtained from fresh samples had a higher percentage of monoterpene hydrocarbons. Variation was observed between the major components of samples of fresh leaves and inflorescences, with eupatoriochrome being the major component in dried samples. Larvicidal activity against Ae. aegypti was considered promising (LC50<100µg/mL) in all samples. The results obtained showed a chemical composition different from that generally presented by P. aduncum. This reinforces the idea of intraspecific variability of essential oils and the need for chemical evaluation between samples even if they belong to the same species.

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