An experiment was conducted on quantification and recovery of Zygogramma bicolorata Pall. (Chrysomelid beetle) to evaluate its role in the biological management on Parthenium hysterophorus (Congress grass). There was significant differences on the defoliation of the plants due to different treatments. Maximum population of 1,34,228 beetles per ha were required in the treatment T5 (40 beetles/plot), where the average days required for defoliation were less i.e. 35.50 days. The next quantified doses recorded were T4 (117450 per ha), T3 (100671 per ha), T2 (83893 per ha) and T1 (67114 per ha). The average days required for defoliation were 40.25, 43.75, 50.75 and 52.25, respectively. The results on average recovery of beetles recorded during 32nd to 38th MW were significant. The highest number of average recovery of beetles was recorded during 35th MW (27 Aug.-2 Sept.) in T5 (243.00) when temp. was in the range of 23.9 to 29.80C and RH 75-88 %. In all, total number of 14030 beetles were recovered between 32nd to 38th MW when the weather condition during this period was 23.4-35.20C temp. and 70-89% RH. There was a negative correlation between temperature and recovery of beetles and significant positive correlation was noticed in the parameters of relative humidity and rainfall.