The efficacy of two commercial products of Bactospine and Bio­fly on Prays citri of lime trees was studied under laboratory and field conditions throughout the two seasons of 1996 and 1997. Laboratory results indicated that the pathogenic effect of Bactospein, Bacillus thu­ringiensis (berliner) was higher than that of Bio-fly. Baeuveria bassiana in spite of the later was applied with higher doses. Bactospine at the rate (2 ccI1 I.W.) affected the larvae more than adults, that treatment re­duced no. of eggs/female by 81.70% and decreased the larval infesta­tion by 90.08%. Bio-fly at the highest concentration (4 cc/1 LW.) re­duced the infestation with the eggs, the larvae and the pupae by 65.83%. 68.45% and 72.55%, respectively. Advanced effects of bacte­rial and fungal treatments on the final reduction rates of P.citri infesta­tion were recorded. Field applications revealed that two sprays with Bac­tospeine or Bio-fly gave good control of P.citri more than one spray. Bactospeine at the rate (2 cc/1 I.W.) and Bio-fly at the rate (2 cc/1 I.W.) reduced the infestation by (89.82-93.43%) and (76.32-78.82%), respectively. In all cases, higher doses of bioinsecticides produced po­tentiation effects of infestation reduction. It is recommended that two sprays of Bactospeine at a rate (2 cc/1 I.W.) is adequate effective to reduce the population of P.citri in lime orchards during the main flower­ing period of trees without need of chemical insecticides.