Larvicidal and residual activity of imidazolium salts against Aedes aegypti (Diptera: Culicidae)

BACKGROUND

Aedes aegypti is an important mosquito species that can transmit several arboviruses such as dengue fever, yellow fever, chikungunya and zika. Because these mosquitoes are becoming resistant to most chemical insecticides used around the world, studies with new larvicides should be prioritized. Based on the known biological profile of imidazolium salts (IS), the objective of this study was to evaluate the potential of six IS as larvicides against Ae. aegypti, as tested against Ae. aegypti larvae. Larval mortality was measured after 24 and 48 h, and residual larvicidal activity was also evaluated.

RESULTS

Promising results were obtained with aqueous solutions of two IS: 1‐n‐octadecyl‐3‐methylimidazolium chloride ( C ₁₈ MImCl ) and 1‐n‐hexadecyl‐3‐methylimidazolium methanesulfonate ( C ₁₆ MImMeS ), showing up to 90% larval mortality after 48 h exposure. C ₁₈ MImCl was more effective than C ₁₆ mIMeS , causing mortality until day 15 after exposure. An application of C ₁₈ MImCl left to dry under ambient conditions for at least 2 months and then dissolved in water showed a more pronounced residual effect (36 days with 95% mortality and 80% mortality up to 78 days).

CONCLUSION

This is the first study to show the potential of IS in the control of Ae. aegypti. Further studies are needed to understand the mode of action of these compounds in the biological development of this mosquito species. © 2017 Society of Chemical Industry

     

Frequency and intensity of pyrethroid resistance through the CDC bottle bioassay and their association with the frequency of kdr mutations in Aedes aegypti (Diptera: Culicidae) from Mexico

BACKGROUND

The control of Aedes aegypti (L.), the main urban vector that causes arboviral diseases such as dengue, Chikungunya and Zika, has proved to be a challenge because of a rapid increase in insecticide resistance. Therefore, adequate monitoring of insecticide resistance is an essential element in the control of Ae. aegypti and the diseases it transmits. We estimated the frequency and intensity (Resistance Frequency Rapid Diagnostic Test [F‐RDT] and Resistance Intensity Rapid Diagnostic Test [I‐RDT]) of pyrethroid resistance in populations of Ae. aegypti from Mexico using the bottle bioassay and results were related to the frequencies of knockdown resistance (kdr) mutations V1016I and F1534C.

RESULTS

All populations under study were resistant to the pyrethroids: bifenthrin (99%), d‐(cis–trans)‐phenothrin (6.3% cis, 91.7% trans) and permethrin (99.5%) according to F‐RDT, and showed moderate to high‐intensity resistance at 10× the diagnostic dose (DD) in I‐RDT. Frequencies of the kdr mutation V1016I in Ae. aegypti populations were correlated with moderate permethrin resistance at 10× DD, whereas F1534C mutation frequencies were correlated with high bifenthrin resistance at 5× DD. Both I1016 and C1535 were highly correlated with high‐intensity phenothrin resistance at 1× to 10× DD.

CONCLUSIONS

This study showed that high frequencies of kdr mutations V1016I and F1534C are reflected in the results of F‐RDT and I‐RDT tests. Bioassays in conjunction with the characterization of genetic resistance mechanisms are indispensable in the strategic and rational management of resistance in mosquitoes. © 2018 Society of Chemical Industry

     

Synthesis and structure–activity relationships of carbohydrazides and 1,3,4‐oxadiazole derivatives bearing an imidazolidine moiety against the yellow fever and dengue vector,Aedes aegypti

BACKGROUND

1,3,4‐Oxadiazole and imidazolidine rings are important heterocyclic compounds exhibiting a variety of biological activities. In this study, novel compounds with oxadiazole and imidazolidine rings were synthesized from 3‐(methylsulfonyl)‐2‐oxoimidazolidine‐1‐carbonyl chloride and screened for insecticidal activities. The proposed structures of the 17 synthesized compounds were confirmed using elemental analysis, infrared (IR), proton nuclear magnetic resonance (¹H‐NMR), and mass spectroscopy.

RESULTS

None of the compounds showed larvicidal activity at the tested concentrations against first‐instar Aedes aegypti larvae. However, nine compounds exhibited promising adulticidal activity, with mortality rates of ≥80% at 5 µg per mosquito. Further dose–response bioassays were undertaken to determine median lethal dose (LD₅₀) values. Compounds 1 , 2b , 2c , 2d , 2 g , 3b , 3c , 3 g, and 3 h were effective, with typical LD₅₀ values of about 5 ? 10 µg per mosquito against female Ae. aegypti. Compounds 2c (bearing a nitro group on the aromatic ring; LD₅₀ = 2.80 ± 0.54 µg per mosquito) and 3 h ( double halogen groups at 2,4 position on the phenyl ring; LD₅₀ = 2.80 ± 0.54 µg per mosquito) were the most promising compounds.

CONCLUSION

Preliminary mode of action studies failed to show consistent evidence of either neurotoxic or mitochondria‐directed effects. Further chemical synthesis within this series may lead to the development of new effective insecticides. © 2017 Society of Chemical Industry

     

PM 7/90(1): Anisogramma anomala

Specific scope

This standard describes diagnostic protocols for Anisogramma anomala ¹ 1 Use of brand names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.
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Specific approval and amendment

Approved in 2009‐09.

     

Curtobacterium flaccumfaciens pv. flaccumfaciens

Specific scope

This standard describes a diagnostic protocol for Curtobacterium flaccumfaciens pv. flaccumfaciens. ¹ 1 Use of names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.

Specific approval and amendment

Approved in 2011‐09.

     

PM 7/40(2): Globodera rostochiensis and Globodera pallida

Specific scope

This standard describes a diagnostic protocol for Globodera rostochiensis and Globodera pallida ¹ 1 Use of brand names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.
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Specific approval and amendment

This Standard was developed under the EU DIAGPRO Project (SMT 4‐CT98‐2252) by partnership of contractor laboratories and intercomparison laboratories in European countries. Approved as an EPPO Standard in 2003–09. Revision approved in 2009–09.

     

PM 4/10(2): Certification scheme for Rubus

Specific scope

This standard describes the production of certified pathogen‐tested material of Rubus.

Specific approval and amendment

First approved in 2004–09. Revised in 2009–09.

     

PM 9/1(2): Bursaphelenchus xylophilus and its vectors: procedures for official control

Specific scope

This standard describes the procedures for official control with the aim of containing and eradicating Bursaphelenchus xylophilus in areas where infestation of susceptible coniferous species by B. xylophilus leads to wilt symptoms.

Specific approval and amendment

First approved in 2002–09. Revision approved in 2009‐09.

     

PM 7/91(1): Gibberella circinata

Specific scope

This standard describes a diagnostic protocol for Gibberella circinata ¹ 1 Use of brand names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.
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Specific approval and amendment

Approved in 2009–09.

     

PP 7/94(1): Hirschmanniella spp.

Specific scope

This standard describes a diagnostic protocol for the genus Hirschmanniella ¹ 1 Use of names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.
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Specific approval and amendment

Approved in 2009–09.

     

PM 7/95(1): Xiphinema americanum sensu lato

Specific scope

This standard describes a diagnostic protocol for Xiphinema americanum sensu lato ¹ 1 Use of names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.
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Specific approval and amendment

Approved in 2009–09.

     

Ceratitis capitata

Specific scope

This standard describes a diagnostic protocol for Ceratitis capitata. ¹ 1 Use of brand names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.

Specific approval and amendment

Approved in 2011–09.

     

PM 7/92(1): Gremmeniella abietina

Specific scope

This standard describes a diagnostic protocol for Gremmeniella abietina ¹ 1 Use of brand names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.

Specific approval and amendment

Approved in 2009–09.

     

PM 7/93(1): Melampsora medusae

Specific scope

This standard describes a diagnostic protocol for Melampsora medusae ¹ 1 Use of brand names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.

Specific approval and amendment

Approved in 2009–09.

     

PM 7/5(2): Nacobbus aberrans sensu lato

Specific scope

This standard describes a diagnostic protocol for Nacobbus aberrans sensu lato ¹ 1 Use of brand names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.
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Specific approval and amendment

Approved in 2000–09. Revision approved in 2009–09.

     

PM 7/23 (2): Xanthomonas axonopodis pv. dieffenbachiae

Specific scope

This standard describes a diagnostic protocol for Xanthomonas axonopodis pv. dieffenbachiae ¹ 1 Use of brand names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.
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Specific approval and amendment

First approved in 2003–09. Revised in 2009–09.

     

PM 9/8(1): Eichhornia crassipes

Specific scope

This standard describes the procedures for control of Eichhornia crassipes.

Specific approval and amendment

First approved in 2009–09.

     

PM 7/18(2): Monilinia fructicola

Specific scope

This standard describes a diagnostic protocol for Monilinia fructicola ¹ 1 Use of names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.
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Specific approval and amendment

First approved in 2002–09. Revised in 2009–09

     

PM 4/16(2): Certification scheme for hop

Specific scope

This standard describes the production of certified pathogen‐tested material of hop.

Specific approval and amendment

First approved in 1996–09. Revised in 2009–09.

     

PM 7/17(2): Guignardia citricarpa

Specific scope

This standard describes a diagnostic protocol for Guignardia citricarpa. ¹ 1 Use of brand names of chemicals or equipment in these EPPO Standards implies no approval of them to the exclusion of others that may also be suitable.

Specific approval and amendment

First approved in 2002–09. Revised in 2009–09.