Screening and evaluation of different algal extracts and prospects for controlling the disease vector mosquito L.

Continual application of synthetic insecticides in controlling mosquito larvae has resulted in several problems as build-up of mosquito resistance beside to negative impacts on human health and environment. Discovering new and affordable bio-insecticidal agents with high efficiency, cost effective and target specific become a crucial need. The current study assessed the larvicidal activity of eight methanolic algal extracts belong to three different algal divisions against the 3 larval instar of L. (Diptera: Culicidae). Comparative studies showed that four species of red and green algal extracts exhibited good larvicidal activity. and (Rhodophyta), and (Chlorophyta) showed higher larvicidal potencies than , , and (Phaeophyta) and (Rhodophyta). The maximum level of toxicity was achieved by exposure to extract with LC (31.13 ppm) followed by (69.85 ppm) then (84.82 ppm) and (97.54 ppm), while the lowest toxicity exhibited by (297.38 ppm) at 72 h post- treatment. The application of LC values of , and extracts affected the activities of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase as oxidative stress markers. An increase of antioxidant enzymes activities was recorded. Therefore, a significant elimination of free radicals, causing toxic effects. Overall, this study casts light on the insecticidal activity of some algal extracts, suggesting the possibility of application of these bio- agents as novel and cost- effective larvicides.