Larvicidal, Ovicidal, and Repellent Activities of Marine Sponge Cliona celata (Grant) Extracts against Culex quinquefasciatus Say and Aedes aegypti L. (Diptera: Culicidae)

Solvent extracts of marine sponge Cliona celata (Grant) were screened for larvicidal, ovicidal, and repellent properties against the filarial vector Culex quinquefasciatus Say and dengue vector Aedes aegypti L. Larvicidal and ovicidal activities of hexane, ethyl acetate, and methanol extracts were tested in four different concentrations ranging as 62.5, 125, 250, and 500？ppm. Among the three solvent extracts of C. celata, methanol extract showed the highest larvicidal activity at 500？ppm against both mosquito species. The LC50 and LC90 values of C. celata methanol extract were recorded as 95.63 and 242.16？ppm against C. quinquefasciatus larvae and 158.40 and 780.16？ppm against A. aegypti larvae, respectively. Ovicidal activity was high in methanol extract, in which 100% ovicidal activity was recorded in C. quinquefasciatus, and 72% ovicidal activity was recorded in A. aegypti at 500？ppm. The hexane extract was found to be the most effective protectant against the adult mosquitoes of both species. The mean protection time recorded in hexane extract was up to 273 and 165？min at 5？mg/cm2 dosage against C. quinquefasciatus and A. aegypti, respectively. Considering these bioactivities, C. celata could be used to obtain some novel pesticidal molecules. 1. Introduction Mosquitoes are the major arthropod vectors and the most dangerous human health pests. The war against mosquitoes using chemical pesticides has failed due to the resistance developed by mosquitoes [1, 2]. Chemical control of mosquitoes is also causing many unwanted effects on human health and nontarget animals. By understanding these side effects of chemicals, people are now showing interest towards biopesticides and botanical formulations, which are considered as eco-friendly. Nature is providing numerous bioactive products against vector mosquitoes in the form of plant products, marine products, microbial products, and other biological derivatives. Culex quinquefasciatus is a major vector of Wuchereria species causing lymphatic filariasis; it is widely distributed in tropical regions with around 120 million people getting infected and 44 million people under clinical manifestation [3]. India alone contributes around 40% of global filariasis burden, and the estimated annual economic loss is about 720 crore Indian rupees [4]. The mosquito Aedes aegypti is more widely distributed in tropical and subtropical regions of the world. It is a major vector of arboviruses causing chikungunya and dengue fever. Natural insecticides are generally pest specific, biodegradable, usually nonallergic to human as