To evaluate the ovicidal and oviposition deterrent activities of five medicinal plant extracts namelyAegle marmelos(Linn.),Limonia acidissima(Linn.),Sphaeranthus indicus(Linn.),Sphaeranthus amaranthoides(burm.f), andChromolaena odorata(Linn.) againstCulex quinquefasciatusandAedes aegyptimosquitoes. Three solvents, namely hexane, ethyl acetate, and methanol, were used for the preparation of extracts from each plant.
Four different concentrations—62.5 parts per million (ppm), 125 ppm, 250 ppm, and 500 ppm—were prepared using acetone and tested for ovicidal and oviposition deterrent activities. One-way analysis of variance (ANOVA) was used to determine the significance of the treatments and means were separated by Tukey's test of comparison.
Among the different extracts of the five plants screened, the hexane extract ofL. acidissimarecorded the highest ovicidal activity of 79.2% and 60% at 500 ppm concentration against the eggs ofCx. quinquefasciatusandAe. aegypti, respectively. Similarly, the same hexane extract ofL. acidissimashowed 100% oviposition deterrent activity at all the tested concentrations againstCx. quinquefasciatusandAe. aegyptiadult females.
It is concluded that the hexane extract ofL. acidissimacould be used in an integrated mosquito management program.
medicinal plant extracts;
Mosquitoes are medically important insects and are considered major public health pests. Mosquitoes transmit many dreadful diseases to humans and other vertebrates; therefore, they have been declared “Public Enemy Number One”. Mosquitoes belonging to the generaAedesandCulexare transmitting dengue, dengue hemorrhagic fever, yellow fever, chikungunya, Japanese encephalitis, and filariasis3 and 4. Mosquito bites cause allergic responses including local skin reactions and systemic reactions such as angioedema and urticaria. Tropical areas are more vulnerable to mosquito-borne diseases and the risk of contracting arthropod-borne illnesses is increased due to climate change and intensifying globalization.
It is imperative to control mosquitoes in order to prevent mosquito-borne diseases and improve public health.Aedes aegyptiis the primary vector of dengue, dengue hemorrhagic fever, and chikungunya. Dengue fever is endemic in south-east Asia including India, Bangladesh, and Pakistan. Dengue fever has become an important public health problem as the number of reported cases continues to increase, especially with more severe forms of the disease such as dengue hemorrhagic fever and dengue shock syndrome or with unusual symptoms such as central nervous system involvement8 and 9.Culex quinquefasciatusis an important vector of lymphatic filariasis in tropical and subtropical regions. It is a pantropical pest and urban vector ofWuchereria bancroftiand is possibly the most abundant house mosquito in towns and cities of tropical countries. According to, about 90 million people worldwide are infected withW. bancrofti,and 10 times more people are at risk of being infected. In India alone, 25 million people harbor microfilaria (mf) and 19 million people suffer from filarial disease manifestations.
In recent years, mosquito control programs have suffered a setback because mosquitoes are developing resistance to synthetic chemical insecticides such as organochlorides, organophosphates and carbamates and insect growth regulators such as methoprene, pyriproxyfen, and diflubenzuron13,14,15 and 16. Moreover, many organophosphates and organochlorides adversely affect the environment and damage biological systems. These side effects of synthetic chemicals prompted many researchers to find environment-friendly alternatives for mosquito management. Literature reveals sufficient amounts of work on the mosquito control potential of plant extracts and plant essential oils18,19,20,21,22,23,24 and 25.
The present study was undertaken to evaluate the ovicidal and oviposition deterrent activities of five medicinal plant extracts namelyAegle marmelos(Linn.),Sphaeranthus indicus(Linn.),Sphaeranthus amaranthoides(burm.f),Limonia acidissima(Linn.), andChromolaena odorata(Linn.) againstAe. aegyptiandCx. quinquefasciatusmosquitoes.