The economical importance and distribution of pear orchards in the structure of all fruit and berry plantings in Ukraine takes the second place after apple. The reason of this is not only the less popularity of a pear comparing to an apple but, first of all, fastidiousness of a pear to planting conditions that significantly reduces its area. In present time Ukraine takes the last but one place in production of pear fruits and leaves behind only Poland [1]. Among factors that cause decrease of pear areal in Ukraine are negative impact of environment, presence of pests and significant spread of causative agents of fungal, bacterial and viral diseases. These factors decline productivity of pear orchards and its profitability and as a consequence make no expediency to create new gardens.According to European scheme of certification, which estimates quality of planting material of pome cultures regarding to international normative documents of European Plant Protection Organization, among the viral agents that cause viral diseases of fruit cultures the most harmful for pear and quince are three viruses of Flexiviridae family: Apple chlorotic leaf spot virus (ACLSV), Apple stem grooving virus (ASGV) and Apple stem pitting virus (ASPV) [3,5]. �hese viruses are rather widespread in rosaceae family especially in apple, pear and quince orchards and have rather wide geographical distribution [6,7]. �he average rate of three viruses of pear plantings in Russia is 20% [2]. It is hard to detect infection in time because ACLSV, ASGV and ASPV belong to the group of latent viruses and most