Sedge is very importance crop in .wetlands of Red River Delta of Vietnam. During 2008 - 2010 many insect pests species damaged sedge and due to absence of methods to control pests lead to farmers to use lots of pesticide chemicals to spray, which destroyed part of the enviromental and had negative effect on human health in the coastal region in Vietnam. Within 3 years research, PPRI have been collected 17 species of insect that have been Identified belong to 12 familie and 6 orders. From all collected pests, sedge hopper is the most important pest for sedge production. Sedge hopper has a three - phase life cycle: its egg, larva and adult. Under lab and greenhouse conditions life cycle of the sedge hopper ranged from 25.23 - 35.69 days depending on food and environmental conditions. A female lays 12.5 eggs within 5.4 days. Adult live 7.58 to 8.44 days. Larvae live from 19.9 - 20.31 days. Sedge hopper has 2 peaks: May - June and September. the authors have done experiments on 3 kinds of pesticides, viz. Bassa 50EC, Conphai 20WP and Actara 25WG. Good results have beentained but pesticides applicati.on must be done when water level is at least 5 cm in the sedge field.