Larvicidal effects of various essential oils against Aedes, Anopheles, and Culex larvae (Diptera, Culicidae)

Abstract

Mosquitoes in the larval stage are attractive targets for pesticides because mosquitoes breed in water, and thus, it is easy to deal with them in this habitat. The use of conventional pesticides in the water sources, however, introduces many risks to people and/or the environment. Natural pesticides, especially those derived from plants, are more promising in this aspect. Aromatic plants and their essential oils are very important sources of many compounds that are used in different respects. In this study, the oils of 41 plants were evaluated for their effects against third-instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. At first, the oils were surveyed against A. aegypti using a 50-ppm solution. Thirteen oils from 41 plants (camphor, thyme, amyris, lemon, cedarwood, frankincense, dill, myrtle, juniper, black pepper, verbena, helichrysum and sandalwood) induced 100% mortality after 24 h, or even after shorter periods. The best oils were tested against third-instar larvae of the three mosquito species in concentrations of 1, 10, 50, 100 and 500 ppm. The lethal concentration 50 values of these oils ranged between 1 and 101.3 ppm against A. aegypti, between 9.7 and 101.4 ppm for A. stephensi and between 1 and 50.2 ppm for C. quinquefasciatus.

Larvicidal and irritant activities of hexane leaf extracts of Citrus sinensis against dengue vector Aedes aegypti L.

“…Natural pesticides derived from plants are a promising tool especially for targeting mosquitoes in the larval stage [6] . Different parts of the Citrus plant i.e.…”

“…Petroleum ether extracts of Vitex negundo leaves offered 8 h of bite protection (2 mg/cm 2 ) by different mosquito species in the field [24,25] . A patented extract of the seeds of Vitex agnus castus was shown effective against mosquitoes resulting in more than 6 h protection against Culex quinquefasciatus and Anopheles stephensi, and 3-4 h against Ae. aegypti [26] .…”

“…The activity of crude plant extracts is often attributed to the complex mixture of active compounds. Natural pesticides derived from plants are a promising tool especially for targeting mosquitoes in the larval stage [6] , but there are some factors that need more investigation in order to extract useful conclusions: light and storing conditions [29] , enantioselectivity of major and minor ingredients [30] , harvesting time and plant material [12] , etc. Further studies are needed to identify the possible role of extract as adulticide, oviposition deterrent and ovicidal agent.…”

“…Lee [11] had tested essential oil of Citrus bergamia against larvae of Ae. aegypti and Culx pipiens, while Amer and Mehlhorn [6] investigated essential oil from Citrus limon against Ae. aegypti and Culex quinquefasciatus, and Anopheles stephensi.…”

“…The botanical extracts from the plant leaves, roots, seeds, flowers and bark in their crude form have been used as conventional insecticides for centuries [5] . Plant products are important natural alternatives to insecticides, as phytochemicals extracted from the whole plant or specific part of the plant using different solvents may also act against mosquitoes as toxicant, growth regulators, repellents and ovipositional deterrent [6][7][8] .…”