Apple leaves of the cvs. Pionier and Romus were observed to have cytological changes under the influence of A. schlechtendali feeding. Cells of lower epidermis and spongy parenchyma were subjected to destruction. No changes, however, were found in the cell layers of palisade parenchyma and upper epidermis.
In the leaves of four apple cultivars with a different degree of susceptibility to the apple rust mite - Aculus schlechtendali (Nal.) the content of some plant components was estimated. It has been found that a long-term feeding of the apple rust mite induces changes in the content of reducing sugars. These changes were significantly varying depending on the apple cultivar.