In the present paper three factors  were assessed in controlling   citrus brown mite Eutetranychus orientalis (Klein) on citrus trees  namely: Efficiency of  two  Acaricides  (Biomectin 5% EC as biocide and Dember 55%SC as chemical compound) ;  efficiency of two types of sprayers (Knapsack motor sprayer Arimitsu (740 L. /Fed.) and conventional motor sprayer Wisconson (1200 L. /Fed.) ; efficiency  of analytical method for the residue analysis of a novel Acaricide Biomectin 5% EC and its dissipation in the citrus fruits. The obtained results reported that,  Dember 55%SC was most effective than  Biomectin 5% EC by using   spraying  methods mentioned above,  the reduction percentages were, 92.17 % and 90.56 % for  Dember 55%SC by using Knapsack motor sprayer Arimitsu (740 L. /Fed.) and conventional motor sprayer Wisconson (1200 L. /Fed.), respectively, while the acaricides Biomectin 5% EC gaves reduction percentages, 88.31 % and 84.41 % by using Knapsack motor sprayer Arimitsu (740  L. /Fed.) and conventional motor sprayer Wisconson (1200 L. /Fed.), respectively. A satisfactory coverage was obtained on citrus trees and ground spray holders. The spectrum of droplets ranging between 111-177 microns (VMD). With sufficient number ranging from 54-224 N/cm².  Abamectin residues were extracted from orange samples and the extract was cleaned up according to QuEChERS method and determined by high-performance liquid chromatography with photo diode array detector (HPLC–DAD). The dissipation half-life time and the pre harvest interval (PHI) of abamectin residues in orange were 2.66 and 14.02 days, respectively in the case of Knapsack motor sprayer Arimitsu .  Whole in the case of conventional motor sprayer Wisconson were 4.85 and 14.1 days, respectively. These results, pointed to that the first method of spraying (Knapsack motor sprayer Arimitsu (740 L. /Fed.)) was more effective than the other method (conventional motor sprayer Wisconson (1200 L. /Fed.)