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

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 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 The effects of plant essential oils on escape response and mortality rate of Aedes aegypti and Anopheles minimus

2015 ◽  
Vol 40 (2) ◽  
pp. 318-326 ◽  
Author(s):  
Sunaiyana Sathantriphop ◽  
Nicole L. Achee ◽  
Unchalee Sanguanpong ◽  
Theeraphap Chareonviriyaphap
Keyword(s):  
Mortality Rate ◽  
Aedes Aegypti ◽  
Essential Oils ◽  
Escape Response ◽  
Plant Essential Oils ◽  
Anopheles Minimus

scholarly journals Synergistic Toxicity of Plant Essential Oils Combined with Pyrethroid Insecticides against Blow Flies and the House Fly

Insects ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 178 ◽  
Author(s):  
Suttida Suwannayod ◽  
Kabkaew L. Sukontason ◽  
Benjawan Pitasawat ◽  
Anuluck Junkum ◽  
Kwankamol Limsopatham ◽  
...  
Keyword(s):  
Essential Oils ◽  
Curcuma Longa ◽  
Antagonistic Effect ◽  
House Fly ◽  
Gas Chromatography Mass Spectrometry ◽  
Fruit Peel ◽  
Pyrethroid Insecticides ◽  
Blow Flies ◽  
Plant Essential Oils ◽  
Filth Flies

Blow flies (Diptera: Calliphoridae) and the house fly (Diptera: Muscidae) are filth flies of medical importance, and control of their population is needed. As insecticide applications have resulted in fly resistance, and the exploration of plant essential oils (EOs) has increased against filth flies, this study assessed the combination of EOs with pyrethoids to enhance toxic efficacy. The EOs of five effective plants were screened initially against the house fly (Musca domestica L.). Their chemical constituent was performed using gas chromatography-mass spectrometry (GC-MS) analysis. The main components of Boesenbergia rotunda (Zingiberaceae) rhizome, Curcuma longa (Zingiberaceae) rhizome, Citrus hystrix (Rutaceae) fruit peel, Ocimum gratissimum (Lamiaceae) seed, and Zanthoxylum limonella (Rutaceae) fruit were δ-3-caren (35.25%), β-turmerone (51.68%), β-pinene (26.56%), p-cumic aldehyde (58.21%), and dipentene (60.22%), respectively. The screening test revealed that the three most effective plant EOs were from B. rotunda, C. longa and O. gratissimum, which were selected for the combination with two pyrethroid insecticides (permethrin and deltamethrin), in order to enhance their synergistic efficacy against the blow flies, Chrysomya megacephala Fabricius, Chrysomya rufifacies Macquart, and Lucilia cuprina Wiedemann, and the house fly. Synergistic action was presented in almost all of the flies tested with permenthrin/deltamethrin/EOs mixtures. It was interesting that the combination of deltamethrin with three EOs showed a synergistic effect on all of the tested flies. However, an antagonistic effect was observed in C. megacephala and M. domestica treated with permethrin-B. rotunda and C. megacephala treated with permethrin-O. gratissimum. The LD50 of insecticides decreased when combined with plant EOs. This alternative strategy will be helpful in developing a formula for effective fly control management.

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