Under green house conditions in Germany, the role of .Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae) and Ctyptothemus montrouzieri (Mulsant) (Coleoptera : Coccinellidae) to reduce the population of the citrus mealybug, Manococcus cirri (Risso) (Homoptera : Pseudocooddae) on citrus trees were studied during 2001 year. Four plots were used. In the first plot (10 adults and 15 larvae/ tree) of C. montrouzieri were released on 1^m June 2001. The percent reduction increased gradually from 0.7 in May (before release) to 74.0 % in October. At the same time, fifteen individuals of L. daayfopii were released in the second plot. The results indicated that the percent of parasitism gradually increased from 0.64 % (before release) in May to 35.7 % in October. In the third plot 10 adults and 15 larvae/tree of C montrouzieri were released on the first of June 2001 and then L. daay/opii was released (August 2001). The percent reduction,of infestation and percent of parasitism were calculated. After released C montrouzieri, the percent reduction of P. cirri in released plot reached 34.5 %, in August. Followed by release of L. dacty/opll in August. Percent of parasitism increased gradually to reach 98.1%.