STUDIES ON THE METHANOLIC EXTRACTS OF MARINE ALGAE FROM THE SOUTH EASTERN COAST OF TAMIL NADU AGAINST THE GROWTH AND DEVELOPMENT OF Spodoptera litura FAB. (LEPIDOPTERA: NOCTUIDAE) - A COSMOPOLITAN PEST IN AGRICULTURE AND HORTICULTURE

摘要

The marine algae belonging to Green, Red and Brown algae, Chaetomorpha antennina (Bory) Kutzing, Laurencia papulosa (C. Agardh) Greville and Padina tetrastomatica Hauck collected from Puducherry, Tuticorin and Rameswaram coast respectively were testedfor their biological activities against Spodoptera litura (Fab.) in Department of Entomology during 2018-19. Comparing the biological activities, L. papulosa showed the highest larval mortality rate (33.33%) followed by/tetrastomatica (26.66%) and C. antennina (6.66%) wherein no mortality was observed in absolute and untreated control respectively. Considering the Insect growth regulator activities of the tested seaweeds, red (L. papillosa) and brown algae (P. tetrastomatica) demonstrated significant pupal malformation and reduced adult emergence wherein the green algae (C. antennina) didn't exhibit pupal malformation and adult emergence. Among the three seaweeds tested, the L. papillosa shown highest biological activities viz, larval mortality, pre-pupal mortality, pupal malformation which resulted in reduced larval to adult emergence ratio followed by P. tetrastomatica and they can be further exploited for their best use in the pest management programmes in future.