This investigation was carried out at Qalubiya Governorate during two successive seasons 2011 & 2012 to study population dynamics of Bemisia tabaci (Genn.), Liriomyza trifolii (Burg.) and Tetrenchys urticae (Koch) on Green bean (Phaseolus vulgaris), and to evaluate the efficiency of five control agents (Agromec gold 1.8 EC, Actellic 50% EC, Achook 0.15, KZ OIL 95% E.C and KZ OIL + Match) when the population densities of these pest were high. The seasonal abundance of B. tabaci and L. trifolii were higher during second season 2012 than that recorded during the first season 2011 with mean number of 262.7 and 247.0 / 10 leaves and 196 and 159 larvae / 10 leaves, respectively. The mean number of T. urticae showed that the population density in the first season was higher than second season with mean number of 96.4 and 65.2 eggs/ 10 leaves and 95.4 and 65.9 movable stage), respectively. On the other hand B. tabaci, L. trifolii and T. urticae had two peaks during this period. Minimum and Maximum temperatures were showed significant negative effects on B. tabaci (egg and nymph) during two seasons. The relative humidity had only significant positive effect on L. trifolii and movable stages of T. urticae at the second season. Minimum and Maximum temperature had significant negative effects on egg of T. urticae at the second season only, The most efficient control agents after general mean of 14 days of spraying was KZ OIL + Match the mortality percentages were 78.7, 81.08 and 81.80% nymph of B. tabaci, larvae L. trifolii and movable stages T. urticae, respectively. on the other hand, the least potent were Agromec gold 1.8 EC on nymph B. tabaci 50.85%, Actellic 50%EC on larvae L. trifolii 60.13% and Achook 0.15 on movable stages T. urticae 65.12%.