Laboratory Evaluation of Larvicidal and Oviposition Deterrent Properties of Edible Plant Oils for Potential Management of Aedes aegypti (Diptera: Culicidae) in Drinking Water Containers

The yellow fever mosquito, Aedes aegypti (Diptera: Culicidae) transmits several devastating arboviruses, including dengue, chikungunya, and Zika virus, making development of inexpensive and eco-friendly strategies for its control an urgent priority. We evaluated the lethality of 13 commonly used plant-derived edible oils against late-third instar Ae. aegypti and then tested the three most lethal oils for stage-specific differences in lethality. We also examined the effects of the most lethal (hempseed), moderately lethal (sunflower and peanut), and least lethal (olive) oils on survival to adulthood and oviposition behavior of gravid females. We hypothesized that the insecticidal activity of edible oils is a function of the content of their linoleic acid, a key fatty acid component with film-forming properties. Among the 13 oils tested, hempseed oil was the most lethal, with an LC50 of 348.25 ppm, followed by sesame (670.44 ppm) and pumpkinseed (826.91 ppm) oils. Oils with higher linoleic acid content were more lethal to larvae than those with low linoleic acid content. Furthermore, pure concentrated linoleic acid was more lethal to larvae compared to any edible oil. In comparison to early instars, late instars were more susceptible to hempseed, sunflower, peanut, and olive oils; these oils also acted as oviposition deterrents, with effective repellency ≥63%. The proportion of larvae surviving to adulthood was significantly reduced in hempseed, sunflower, peanut, and olive oil treatments relative to controls. Our results suggest that some edible plant oils have potential as effective, eco-friendly larvicides, and oviposition deterrents for controlling container-dwelling mosquitoes, especially in resource-limited settings.

THE EFFECT OF ESSENTIAL OIL MIXTURES ON MORTALITIES AND OVIPOSITION DETERRENTS OF Crocidolomia pavonana AND Helopeltis antoniierrents Of Crocidolomia Pavonana And Helopeltis Antonii

<p class="IsiabstrakIndonesia">Essential oil, such as citronella, lemongrass, ageratum, and clove are known to be toxic and repel certain pests. Mixing two or more essential oils are expected increasing their insecticidal properties. The experiments aimed to examine the effect of essential oils mixtures (EOs) on mortalities and oviposition deterrents of <em>Crocidolomia pavonana</em> and <em>Helopeltis antonii</em>. The experiments were conducted at the laboratory and green house of the Indonesian Spices and Medicinal Crops Research Institute. The tested mixtures were citronella and clove (CiC); lemongrass and clove (LC); ageratum and clove (AC); individual EO; control 1 (water + emulsifier); control 2 (water) at 0.5% concentration for all treatments. The ratio used were 1:1, 1:2, 1:4, 2:1 and 4:1. Parameters observed were the mortalities of <em>C. pavonana</em> larvae and <em>H. antonii</em> nymphs; and the ovipositions deterrents of both insects. The CiC and LC mixtures gave low mortality (&lt;50%) to <em>C. pavonana</em> larvae, while AC at ratios 1:1, 1:2,1:4 less than 20%, AC 2:1 and 4:1 &gt;60% and the individual ageratum oil caused 77.5% mortalities. The CiC 1:1 and LC (1:1, 1:2, and 4:1) showed &gt;40% mortalities of <em>H. antonii, whereas </em>the AC in all ratios enhanced the nymph mortalities. The number of eggs laid by <em>C. pavonana</em> at CiC and LC in all ratios were around 50-60% lower than individual EO. The mixture of AC 1:4 and 4:1 produced eggs nearly 50% lower than clove treatment. The CiC and LC at 1:1 produced the lowest numbers of egg laid by <em>H. antonii</em>, while AC 1:4 reduced 70% eggs laid compared to individual EO.</p>