Plant-Derived Repellents

Since ancient times, plant products were used in various aspects. However, their use against pests decreased when chemical products became developed. Recently, concerns increased with respect to public health and environmental security requiring detection of natural products that may be used against insect pests. In a study, 41 plant extracts had been evaluated against the yellow fever mosquito, Aedes aegypti , the malaria vector, Anopheles stephensi , and the filariasis and encephalitis vector, Culex quinquefasciatus (Diptera: Culicidae) using the skin of human volunteers to find out the protection time and repellency. The five most effective oils were those of Litsea (Litsea cubeba), Cajeput (Melaleuca leucadendron), Niaouli (Melaleuca quinquenervia), Violet (Viola odorata), and Catnip (Nepeta cataria), which induced a protection time of 8 h at the maximum and a 100 % repellency against at least two species. This effect needs, however, a peculiar formulation to fix them on the human...