TOXICITY AND SUBLETHAL EFFECTS OF Artemisia annua Linnaeus ON Aedes aegypti (Linnaeus), Aedes albopictus (Skuse), Anopheles sinensis Wiedemann AND Culex quinquefasciatus Say
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Date
2014-08
Authors
XIONG, CHEAH SHAO
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Abstract
Artemisia annua is well known for its strong antimalarial properties; however, limited studies were conducted on the effects of the plant against mosquitoes. This study focuses on the larvicidal activity and sublethal effect of a crude extract of A. annua against Aedes aegypti, Aedes albopictus, Anopheles sinensis and Culex quinquefasciatus, and its effect on the oviposition and the ovicidal activities of the mosquitoes. Dried cells of A. annua from cell suspension culture were extracted using hexane. Artemisia annua extract showed moderate larvicidal effects against the tested mosquitoes. Anopheles sinensis, Ae. albopictus and Ae. aegypti with LC50 values of 244.55 ppm, 254.96 ppm and 276.14 ppm, respectively recorded significantly higher larval mortality compared with Cx. quinquefasciatus with LC50 value of 374.99 ppm at 24 hours post-treatment. The LC50 and LC95 values decreased at 48 hours post-treatment. The fecundity of Ae. albopictus and An. sinensis was significantly reduced in the parental generation (p < 0.05) while hatchability of eggs was significantly reduced for Ae. aegypti and An. sinensis after treatment with sublethal dosage of A. annua extract (p < 0.05). Females of Ae. aegypti showed significant reduction in size compared with the control after treatment with sublethal dosage of A. annua extract (p < 0.05). Females of An. sinensis had significant shorter life span under laboratory condition after treatment with sublethal dosage of A. annua extract (p < 0.05). Only Cx. quinquefasciatus did not show any marked differences in the sublethal effect tests. All the mosquito species did not show any marked differences in F1 generation. The
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results indicated that A. annua extract showed concentration dependent oviposition deterrent activity. At 500 ppm, the percentage of effective repellency was more than 85 % compared with the control for all species with oviposition activity index values of - 0.94, - 0.84, - 0.95 and - 0.78 for Ae. aegypti, Ae. albopictus, An. sinensis and Cx. quinquefasciatus, respectively. In ovicidal assay, the percentage hatchability of eggs after treatment with 500 ppm of A. annua extract was significantly lower than the control (p < 0.05) with a percentage reduction of 45.5 %, 47.5 %, 54.7 % and 17.6 % for Ae. aegypti, Ae. albopictus, An. sinensis and Cx. quinquefasciatus, respectively
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TOXICITY AND SUBLETHAL EFFECTS