Population of tetranychidae mites on apple trees and methods of restraining the number of resistant races in crimea

Analysis of apple tree phytosanitary state showed that the species composition of phytophage mites is labile and is subject to a constant shift of the share ratio. In 2012-2013, the apple orchards of Crimea were dominated by Amphytetranychus viennensis Zacher. Its share in the acarocomplex was 80%. Since 2014, the ratio has changed towards prevalence of Panonychus ulmi Koch. - 50%. With this, share of A. viennensis decreased to 25.0%. In some years there was mass reproduction of Tetranychus turkestani Ug et Nik and Tetranychus urticae Koch. The number of phytophage mites during the growing season depends on a number of factors: settlement to new areas, interspecies competition, reduction of feed base, occurrence of fungal diseases epidemics, increase in the number of natural enemies. The dependence of the phytophage mites population density on the numerical value of hydrothermal moisture index (HMI) was established: the higher the average daily air temperature in the absence of precipitation, the higher the population on the leaf apparatus. Appearance of resistant P. ulmi races to five acaricides belonging to different chemical classes was established with the following active substances: spirodiclofen, fenpyroximate, pyridaben, fenazaquin, tebufenpyrad. A. viennensisshowed the appearance of acaricide-resistant races with active substances pyridaben and tebufenpyrad. In connection with the decrease in acaricide effectiveness against spider mites in the industrial apple tree plantations of Crimea, an anti-resistant protection strategy has been developed using predatory Phytoseiidae mites - Phytoseiulus persimilis Ath. - H, Neoseiulus californicus McGregor, Amblyseius andersoni Chant.