Abstract:
The repellent activity of essential oils of lemon eucalyptus (Eucalyptus maculata citrodion), rue (Ruta
chalepensis), oleoresin of pyrethrum (Chrysanthemum cinerariaefolium) and neem (Azadiracta indica)
have been field tested as 40%, 50% and 75% solutions in coconut oil against populations of mosquitoes con sisting mainly of Mansonia in Gambella, western Ethiopia. A latin square design was used to randomize the
test subjects for possible individual differences for mosquito attraction. Repellency was evaluated as the
percentage protection. Deet was included in the study for comparison. All the plant products manifested
repellency. At 50% concentration at which the highest repellency was recorded the protection was 91.6%,
87.0%, 96.0%, 97.9% for rue, neem, pyrethrum and deet, respectively. The essential oil of lemon eucalyptus
was not tried at this concentration. At a 40% concentration deet, lemon eucalyptus and pyrethrum were
significantly (p < 0.05) more effective than rue and neem. At a 50% concentration, deet and pyrethrum were
significantly better (p < 0.05) than rue and neem. At a 75% concentration concentration, deet and lemon
eucalypus performed significantly better (p < 0.05) than pyrethrum and neem. The difference between pyre thrum and neem was also significant (p < 0.01). Copyright © 2003 John Wiley & Sons, Ltd.
