1. Exploring natural approaches to enhance control of Zika mosquito populations
María Archevald-Cansobre
Edmund Norris, Graduate Assistant
Joel R. Coats, Ph.D., mentor

2. Background:
Up to one million people die from mosquito- borne diseases like Zika, malaria and dengue each year
Insecticide use for mosquito population control methods
Insecticide-resistant populations
Changes in target site of action
Metabolic detoxification
others

3. Plant essential oils:
Abundant in aromatic plants; peppermint, eucalyptus, cedarwood
Composed of a mixture of volatile, organic compounds; terpene family
Resource to enhance synthetic insecticides in the market

4. Pro-insecticides: Azinphos-methyl and Chlorfenapyr
Not traditionally used against mosquito populations
Metabolized into active insecticides after entering the host
Azinphos-methyl
Chlorfenapyr

5. Hypothesis:
Plant essential oils can enhance
pro-insecticides, azinphos-methyl
and chlorfenapyr

6. + Methods: -or- (%effect of mixture) - (%effect of insecticide)
Mixed discrete doses of the insecticides with various plant oils
5% oil concentration
Topical Applications Protocol
(WHOPES Guidelines for testing 2006)
At least 5 replicates/treatment
25 mosquitoes/replicate
Acetone control
Enhancement equation
0%= no enhancement
100%= 2x efficacy
-or-
(%effect of mixture) - (%effect of insecticide)
(%effect of insecticide)
x 100

7. Results: Azinphos methyl + plant oils 5%
Oil # Oil # Oil # Oil # Oil # Oil # Oil # Oil # Oil #9

8. Results: Chlorfenapyr + plant oils 5%
Oil # Oil # Oil # Oil # Oil # Oil # Oil # Oil #8

9. Results:
Various plant essential oils demonstrate potential enhancement of pro-insecticides
Non-toxic, 5% concentrations of plant oils resulted in:
Up to 49% enhancement in Azinphos methyl
Up to 500% enhancement in Chlorfenapyr
Enhancing and antagonizing activity observed
Higher antagonism observed for Azinphos-methyl
Higher enhancement potential observed for Chlorfenapyr

10. Future Steps:
Explore enhancement and/or antagonism of other plant oil and insecticide mixtures
Enhancement mechanisms (increased toxicity, cuticle penetration, detoxifying enzymes)

11. Acknowledgements
Entomology/Toxicology Research Group