Larvicidal effect of crude extracts of some marine plants (mangrove and seagrasses) on mosquitoes of Culex pipiens

Marine halophytes (mangroves and sea grasses) were collected from the Red Sea coast of Egypt and tested for their mosquitocidal activities. The toxicities of mangroves Avicennia marina Rhizophora mucronata, and seagrasses Thalassodendron ciliatum, Halodule uninervis and Halophilia stipulacea were examined against lab. Strain of 3rd instar larvae of Culex pipiens. Results showed that extracts of seeds and leaves of Avicennia marina were more effective than other parts of the same plant as well as of the leaves of Rhizophpra mucronata against 3rd instar larvae of Culex pipiens mosquito. On the other hand, comparison of the toxicities of the three species of sea grasses showed that crude extract of Halodule uninervis was more active against 3rd instar larvae of mosquito Cu pipiens than crude extracts of Thalassodendron Ciliatum and Halophilia stipulacea. In view of these results, the purified active compounds from the most effective samples found in our studies could be effective in killing mosquito larvae or repelling adult female mosquitoes in an economic and safe manner.