Larvicidal effects of aqueous extracts

A screening for larvicidal activity of plant extracts with some known medicinal attributes could lead to the discovery of new agents for pest and vector control. There is an interest in the biotechnology world for developing plant-based insecticides. Many researches were conducted in this regard.
Larvicidal effects of aqueous extracts of Balanites
aegyptiaca (desert date) against the larvae of Culex
pipiens mosquitoes
The effect of aqueous extracts of the fruit pulp, seed kernel, roots, bark, and leaves of Balanites
aegyptiaca Del. (Zygophyllacea) against the larvae of the Culex pipens mosquito was investigated. The fourth instars larvae of C. pipiens mosquitoes were exposed for three days to a 2.0% aqueous extracts of fruit pulp, seed kernel, roots, bark, and leaves. All the extracts showed larval mortality with the greatest rate being greatest with the aqueous root extract. Aqueous extracts of leaf, fruit pulp, and seed kernel showed less larval mortality.

larvicidal effects of plant extracts against Spodoptera litura (F.), Aedes aegypti L. and Culex quinquefasciatus
Antifeedant and larvicidal activity of the acetone, chloroform, ethyl acetate, hexane and methanol leaf extracts of Ocimum canum, Ocimum sanctum and Rhinacanthus nasutus were studied against fourth instar larvae of Spodoptera litura (Lepidoptera: Noctuidae), Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae). These plants are abundantly found in the region of Chitheri Hills, Dharmapuri District, India. All extracts showed moderate larvicidal effects but the highest larval mortality rate was shown by the methanol extract of O. canum, R. nasutus and acetone extract of O. sanctum against the larvae of S. litura.

Larvicidal activity of some Euphorbiaceae plant extracts against Aedes aegypti and Culex quinquefasciatus
The early fourth instar larvae of Aedes aegypti L. and Culex quinquefasciatus were used for testing the Larvicidal activity of ethyl acetate, butanol, and petroleum ether extracts of five species of Euphorbiaceae plants, Jatropha curcas, Pedilanthus tithymaloides, Phyllanthus amarus, Euphorbia hirta, and Euphorbia tirucalli. after 24 h of exposure, the larval mortality rate was observed. the highest larval mortality was found in petroleum ether extract.

For more details on this topic, visit the links:
http://www.academicjournals.org/AJB/PDF/...an%202.pdf
http://www.springerlink.com/content/dt5417q761l35hl1/
http://www.springerlink.com/content/j382l86287575874/
http://www.idosi.org/aje/2(2)09/5.pdf
http://www.icmr.nic.in/ijmr/2009/july/0711.pdf

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