Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes.
Background The standard operating procedure for testing the susceptibility of adult mosquitoes to neonicotinoid or butenolide insecticides recommends using a vegetable oil ester (Mero) as a surfactant. However, there is growing evidence that this adjuvant contains surfactants that can enhance insect...
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ftdoajarticles:oai:doaj.org/article:93834ced22984f28acdb03aedc421a52 2024-09-09T19:27:18+00:00 Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes. Fred A Ashu Caroline Fouet Marilene M Ambadiang Véronique Penlap-Beng Colince Kamdem 2023-11-01T00:00:00Z https://doi.org/10.1371/journal.pntd.0011737 https://doaj.org/article/93834ced22984f28acdb03aedc421a52 EN eng Public Library of Science (PLoS) https://doi.org/10.1371/journal.pntd.0011737 https://doaj.org/toc/1935-2727 https://doaj.org/toc/1935-2735 1935-2727 1935-2735 doi:10.1371/journal.pntd.0011737 https://doaj.org/article/93834ced22984f28acdb03aedc421a52 PLoS Neglected Tropical Diseases, Vol 17, Iss 11, p e0011737 (2023) Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 article 2023 ftdoajarticles https://doi.org/10.1371/journal.pntd.0011737 2024-08-05T17:50:02Z Background The standard operating procedure for testing the susceptibility of adult mosquitoes to neonicotinoid or butenolide insecticides recommends using a vegetable oil ester (Mero) as a surfactant. However, there is growing evidence that this adjuvant contains surfactants that can enhance insecticide activity, mask resistance and bias the bioassay. Methodology/principal findings Using standard bioassays, we tested the effects of commercial formulations of vegetable oil-based surfactants similar to Mero on the activity of a spectrum of active ingredients including four neonicotinoids (acetamiprid, clothianidin, imidacloprid and thiamethoxam) and two pyrethroids (permethrin and deltamethrin). We found that three different brands of linseed oil soap used as cleaning products drastically enhanced neonicotinoid activity in Anopheles mosquitoes. At 1% (v/v), the surfactant reduced the median lethal concentration, LC50, of clothianidin more than 10-fold both in susceptible and in resistant populations of Anopheles gambiae. At 1% or 0.5% (v/v), linseed oil soap restored the susceptibility of adult mosquitoes fully to clothianidin, thiamethoxam and imidacloprid and partially to acetamiprid. By contrast, adding soap to the active ingredient did not significantly affect the level of resistance to permethrin or deltamethrin suggesting that vegetable oil-based surfactants specifically enhance the potency of some classes of insecticides. Conclusions/significance Our findings indicate that surfactants are not inert ingredients, and their use in susceptibility testing may jeopardize the ability to detect resistance. Further research is needed to evaluate the potential, the limitations and the challenges of using some surfactants as adjuvants to enhance the potency of some chemicals applied in mosquito control. Article in Journal/Newspaper Arctic Directory of Open Access Journals: DOAJ Articles Arctic PLOS Neglected Tropical Diseases 17 11 e0011737 |
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Directory of Open Access Journals: DOAJ Articles |
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English |
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Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 |
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Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 Fred A Ashu Caroline Fouet Marilene M Ambadiang Véronique Penlap-Beng Colince Kamdem Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes. |
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Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 |
description |
Background The standard operating procedure for testing the susceptibility of adult mosquitoes to neonicotinoid or butenolide insecticides recommends using a vegetable oil ester (Mero) as a surfactant. However, there is growing evidence that this adjuvant contains surfactants that can enhance insecticide activity, mask resistance and bias the bioassay. Methodology/principal findings Using standard bioassays, we tested the effects of commercial formulations of vegetable oil-based surfactants similar to Mero on the activity of a spectrum of active ingredients including four neonicotinoids (acetamiprid, clothianidin, imidacloprid and thiamethoxam) and two pyrethroids (permethrin and deltamethrin). We found that three different brands of linseed oil soap used as cleaning products drastically enhanced neonicotinoid activity in Anopheles mosquitoes. At 1% (v/v), the surfactant reduced the median lethal concentration, LC50, of clothianidin more than 10-fold both in susceptible and in resistant populations of Anopheles gambiae. At 1% or 0.5% (v/v), linseed oil soap restored the susceptibility of adult mosquitoes fully to clothianidin, thiamethoxam and imidacloprid and partially to acetamiprid. By contrast, adding soap to the active ingredient did not significantly affect the level of resistance to permethrin or deltamethrin suggesting that vegetable oil-based surfactants specifically enhance the potency of some classes of insecticides. Conclusions/significance Our findings indicate that surfactants are not inert ingredients, and their use in susceptibility testing may jeopardize the ability to detect resistance. Further research is needed to evaluate the potential, the limitations and the challenges of using some surfactants as adjuvants to enhance the potency of some chemicals applied in mosquito control. |
format |
Article in Journal/Newspaper |
author |
Fred A Ashu Caroline Fouet Marilene M Ambadiang Véronique Penlap-Beng Colince Kamdem |
author_facet |
Fred A Ashu Caroline Fouet Marilene M Ambadiang Véronique Penlap-Beng Colince Kamdem |
author_sort |
Fred A Ashu |
title |
Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes. |
title_short |
Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes. |
title_full |
Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes. |
title_fullStr |
Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes. |
title_full_unstemmed |
Vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes. |
title_sort |
vegetable oil-based surfactants are adjuvants that enhance the efficacy of neonicotinoid insecticides and can bias susceptibility testing in adult mosquitoes. |
publisher |
Public Library of Science (PLoS) |
publishDate |
2023 |
url |
https://doi.org/10.1371/journal.pntd.0011737 https://doaj.org/article/93834ced22984f28acdb03aedc421a52 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
PLoS Neglected Tropical Diseases, Vol 17, Iss 11, p e0011737 (2023) |
op_relation |
https://doi.org/10.1371/journal.pntd.0011737 https://doaj.org/toc/1935-2727 https://doaj.org/toc/1935-2735 1935-2727 1935-2735 doi:10.1371/journal.pntd.0011737 https://doaj.org/article/93834ced22984f28acdb03aedc421a52 |
op_doi |
https://doi.org/10.1371/journal.pntd.0011737 |
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PLOS Neglected Tropical Diseases |
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17 |
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11 |
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e0011737 |
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