|MadSci Network: Botany|
I doubt that a live potted plant will be able to repel mosquitoes because the chemicals that may repel mosquitoes are still within the plant. There is research that indicates that a chemical extracted from Euodia spp., also called Melicope, can kill mosquito larvae. However, that would require that the chemical be extracted from the plant and sprayed on standing water where the mosquitoes larvae might be present. Plants with mosquito repellant properties include lemon thyme (Thymus X citriodorus), citronella grass (Cymbopogon nardus), catnip (Nepeta cataria) and mosquito geranium (Pelargonium ‘Citrosa’). These plants repel mosquitoes but only if the leaves are crushed or extracted and the juice or extract placed on the skin. However, few of the plant extracts were as effective as DEET, an artificial mosquito repellant. Catnip was better than DEET in some tests. To do an experiment to test a live plant's ability to repel mosquitoes you could try something like the following: 1. Build two identical insect-tight chambers each about 1 meter square. 2. Place a potted plant in one end of the chamber. 4. In the second chamber place an identical pot filled with the same soil but no plant. 5. Release 100 mosquitoes into each of the two chambers. 6. Watch the mosquitoes to see if any land on the plant. If the plant repels mosquitoes, they should stay as far away from the plant as possible. You could also try your arm-in-cage test but that would probably require that you use leaf extracts on the arm. The last reference mentioned a simple experiment where leaf extract was rubbed on one side of the interior of a tube. Mosquitoes were placed in the tube, and it was determined if more mosquitoes landed on the treated or untreated side. References I. Ramli, N.H. Kamarulzaman, K. Shaari, G.C.L. 2004. p-O-Geranylcoumaric Acid from Melicope Lunu-Ankenda. Natural Product Research. 18: 289-294. Mosquito Repellent Plants Jeyabalan, D., Arul N., and Thangamathi, P. 2003. Studies on effects of Pelargonium citrosa leaf extracts on malarial vector, Anopheles stephensi Liston. Bioresource Technol. 89:185-189. Cymbopogon nardus Catnip oil may repel mosquitoes better than spray
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