10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 2 2013 (April - June) The 96 hrs LC lessThan sub greaterThan 50 lessThan /sub greaterThan values for malathion and glyphosate was determined to be 9.1 ppm and 5.5 ppb, respectively on the fairy shrimp, lessThan i greaterThan Streptocephalus dichotomus lessThan /i greaterThan preadults. The 1/5 lessThan sup greaterThan th lessThan /sup greaterThan of 96 hrs LC lessThan sub greaterThan 50 lessThan /sub greaterThan of malathion (2.0 ppm) and glyphosate (1.1 ppb) respectively was chosen. The sub lethal toxic effect of each of these pesticides on the acetylcholinesterase activity (AchE) of lessThan i greaterThan S. dichotomus lessThan /i greaterThan was assayed on days 0 and 15 lessThan sup greaterThan th lessThan /sup greaterThan of exposure, and found to be significantly decreased (0.13±0.006 nmol/mg/min) in malathion than in glyphosate when compared with control. Furthermore, the contents of selected biochemical constituents (total protein, carbohydrate and lipid) of lessThan i greaterThan S. dichotomus lessThan /i greaterThan were estimated on '0', 15 lessThan sup greaterThan th lessThan /sup greaterThan and 30 lessThan sup greaterThan th lessThan /sup greaterThan days of exposures, and found to be decreased significantly on 30 lessThan sup greaterThan th lessThan /sup greaterThan day in both the pesticides when compared to control. The results indicated the fact that these pesticides are toxic to lessThan i greaterThan S. dichotomus lessThan /i greaterThan at the tested concentrations. ARUN KUMAR M.S AND A. JAWAHAR ALI AchE, Malathion, Glyphosate, S. dichotomus, Protein, Carbohydrate, Lipid. 966-972