Field experiments on seasonal abundance and evaluation of insecticides against mussel scale, Lepidosaphes piperis Gr. in pepper were conducted at Zonal Horticultural Research Station, Mudigere during 2006-07 and 2007-08. The results revealed that the scale population ranged from 0.365 to 28.43 and 12.93 to 52.1 on leaves and twigs, respectively during different months. The peak population was noticed during Feb-March and April-May months both on leaves and twigs. The population exhibited positive correlation with sunshine hours (r=0.6819) and maximum temperature (r=0.7957) and negative correlation with rainfall (r=-0.293), maximum relative humidity (r=-0.3016) and minimum temperature (r=-0.5384). The spray of acetamiprid 20 SP @ 0.3 g/l, thiamethoxam 25WG@ 1 g/l and carbosulfan 20EC @ 2 ml/l were found effective against mussel scale with population of 5.45 and 11.38; 6.38 and 12.79; 7.12 and 13.64 on leaves and twigs, respectively compared to econeem plus @ 2.5 ml/l (13.24 and 30.06) and NSKE 5% @ 50 ml/l (16.64 and 5 7.18). Among organic products neem oil @ 5 ml/l and fish oil @ 3 g/l (3.32 and 11.22; 2.68 and 9.79) significantly reduced the scale population compared to econeem @ 2.5ml/l and monocrotophos 36SL @ 1.5 ml/l (l6.98 and 29.31; 3.16 and 13.14 on leaves and twigs, respectively).