Trials were carried out under field conditions to evaluate  the efficacy of the predatory mite, Euseius scutalis (A-H.) against citrus brown mite, Eutetranychus orientalis (Klein) on citrus trees atEL BEHERA Governorate. The predatory mite E.scutalis was released on January 2010 at rate 40-70 adult females per tree (according to the size of tree) when infestation level of the prey citrus brown mite E.orientalis reached 4.2 individuals per leaf of citrus. The percentage reduction of prey popula­tion density was 82.88 after 12 months of release, then decreased to 52.46% after 21 months. So, it was felt necessary to carry out the sec­ond release of E.scutalis on November 25, 2011 when the infestation  with moving stages of E.orientalis reached 4.9 individuals per leaf. The reduction percentage of E.orientalis after 13 months from the second release of the predatory mite was 70.19%. To serve the biological control programme.  The side effect of 9 acaricides and some mineral oils were also tested against the predator motile stages under field condition three acaricides (Vertimec, Cascade and Ortes) and mineral oils were harmless to the predatory mite, E.scutalis Thus, it is advisable to use these compounds in IPM programme.