Powdery mildews rank among the most important diseases of agricultural and ornamental plants. Powdery mildew of apples is becoming increasingly problematic as many apple varieties preferred by consumers are susceptible to it. As resistance to many chemical fungicides becomes more common, integrated management with good resistance management is critical. The purpose of this study – evaluation of the biological efficacy of the microbial agents Pseudomonas fluorescens AP-33 (manufactured as Rizoplan) and Trichoderma lignorum M-10 (manufactured as Trichodermin SC) in control of the apple powdery mildew (Podosphaera leucotricha (Ellis & Everh.) E.S.Salmon). The experiments were mounted on the experimental lot of the Institute of Genetics, Physiology and Plant Protection (Moldova State University), on the apple trees, Reinette Simirenko variety, in 8 variants, 3 repetitions, with 3 trees per repetition. According to the obtained results, the highest attack frequency 27.7% and intensity of the disease 14.5% were in the Control variant (untreated control) and the lowest frequency 4.0% and intensity of disease development 1.4% were in the Standard variant (Jeck Pot EC, 0,4 l/ha). Whereas in the variants where biological preparations were used, the frequency was between 6.0% and 13.0%, and the intensity of the development of the disease between 2.5% and 6.3%. The attack frequency reached 9.0 - 10.3% with a disease intensity of 4.1 - 4.3% when mixture of the biological plant protection products Rizoplan and Trichodermin SC was used. The biological efficacy of biological products Rizoplan and Trichodermin SC after foliar application in the control of the powdery mildew was as follows: Rizoplan 2.0 l/ha – 56.5%; Rizoplan 3.0 l/ha - 64.1%; Trichodermin SC 2.0 l/ha - 81.4%; Trichodermin SC 3.0 l/ha - 82.7% and for mixtures Rizoplan + Trichodermin SC 2.0 l/ha - 70.3%; Rizoplan + Trichodermin SC 3.0 l/ha -71.7%. The best result in control of the Podosphaera leucotricha on apples was obtained for biological preparation Trichodermin SC 3.0 l/ha. The biological efficiency was 82.7%, which was at the level of the Standard variant.