The effectiveness of strobilanthes crispus as repellent against aedes aegypti / Nur Azma Abdul Wahab

The incidence of dengue fever increased dramatically and one of major public concern in Malaysia. In 2013, the number of dengue cases in Malaysia keeps increasing. A mosquito repellent is a substance applied to skin, clothing, or other surfaces which discourages insects (and arthropods in general) from landing or dimbing on that surface. Mosquito repellent is use for adult Aedes Aegypti Mosquito which the vector that cause dengue fever. The use of natural repellency is more environmentally friendly.To determine the effectiveness of selected plant extractions of Strobilanthes Crispus as mosquito repellent against Aedes Aegypti mosquito.The essential oil of Strobilanthes Crispus was obtained by soxhlet extraction. The extraction is use with methanol solvent. The essential oil from extraction of Strobilanthes Crispus be divided into different concentration and test system based on Buecher.et.al. The 15 blood­ starved female mosquito of Aedes Aegypti were removed into a test plastic cage (4 x 5 x 18 cm) and the essential oil of Strobilanthes Crispus was applied randomly onto five circles (29mm diameter) with marked area. Each marked areas on forearm was applied different concentration of 2.84 µgcm-², 3.22 µgcm-², 3.60 µgcm-² and 3.79 µgcm-² Extraction of Strobilanthes Crispus result in maximum repellency for 60s, 90s, 120s are 88.23%, 61.11% and 58.82% at concentration 3.79 µgcm-² compare to repellency of DEET result in 100% protection at concentration of 1.89 µgcm-². The ED50 of Strobilanthes Crispus for 60s, 90s, 120s are 3.37 µgcm-², 3.61µgcm-² and 3.60 µgcm-² while for DEET 0.42 µgcm-², 0.30 µgcm-² and 0.34 µgcm-². For ED90 of Strobilanthes Crispus for 60s, 90s and 120s are 4.22 µgcm-², 4.77 µgcm-² and 5.42 µgcm-² when compare to DEET result are 0.73 µgcm-², 0.53µgcm-² 0.58 µgcm2.The Strobilanthes Crispus was potential as alternative of repellent to DEET (N, N-diethyl-meta-toluamide) for controlling Aedes Aegypti Mosquito.