Studies on Methanolic Extract of Brown Algal Seaweed Liagora ceranoides J.V. Lamouroux from Southern Coast of Tamilnadu: In vitro Anti-Insect Properties and Phytochemicals

Red algal seaweed Liagora ceranoides collected from Rameswaram coast, Tamilnadu, India was investigated for its repellent, antifeedant, larvicidal, insect growth regulatory activities on Spodoptera litura during 2016-18. Larvicidal action of methanol extract of sea weed was observed from first day of treatment and exhibited gradual increase in mortality up to fifth day. The seaweed’s methanol extracts @200 μl/L concentration resulted 80.00 per cent larval mortality and the survived larvae got pupated. No repellent and antifeedant activity was observed among the treatments. Adult emergence was not observed at 200 μl/L concentration with a pupal: adult conversion ratio of 1:0.00 whereas in control and solvent control the ratio was 1:1.00. Twenty- three phytochemicals were identified in L. ceranoides using GC-MS detection system (Gas Chromatography-Mass Spectrometry) respectively and few of them may be responsible for ant-insect properties.