Population dynamics of Dicladispa armigera (Olivier) was studied in two sites of Barak valley of Assam, viz., Dargakona and Katigarah in three seasons (Amon, Boro, Aus) for two years (2003-2005). Maximum population was recorded on Ranjit variety (15.2 ± 2.31 nos. / 5 sweeps) on 1st week of October, 04 followed by 12.2 ± 1.67 nos. / 5 sweeps, on 3rd week of September, 04 during Amon seasons in Katigarah. Kala birane variety showed

maximum population (4.4 ± 0.32 nos. / 5 sweeps) on 1st week of September, 03. Whereas Dargakona witnessed maximum population (6.4 ± 0.14 nos. / 5 sweeps) on Ranjit Variety during the 3rd week of October, 04 followed by 1st week of October, 04 where population was recorded to be 5.8 ± 0.14 nos. / 5 sweeps. Bio-effectiveness was studied for two years with two bio-pesticides viz. Calpaste and Larvocel where Larvocel (0.1%) afforded maximum (86.38%) mortality of insect-pests after seven days of application during second year. All the treatments proved to be significant (p<0.05) over control (water spray). Toxicity persisted up to ten days after application.