A study was conducted in the IO Experimental Ecological Orchard in 2010-2014 to assess the severity of occurrence of the apple rust mite Aculus schlechtendali (Nal.) on apple trees of the cultivars ‘Pinova’ and ‘Topaz’ grown at two spacings: 3×1 m and 3.5×3 m. In wintertime, the recorded numbers of females overwintering under the buds on annual shoots were low: 0-3.6 females per bud. The number of rust mites in the summer was the lowest in 2011, with an average of 0.6-11.8 individuals per cm2 of leaf surface area, and the highest in 2014, when it averaged 42.8-71.9 individuals / cm2. The largest numbers of the apple rust mite were recorded on the leaves of trees of the cultivar ‘Pinova’ and the leaves of trees of both cultivars grown at the spacing of 3×1 m.