Biological stability of varieties of black currant against Cecidophyopsis ribis Westw. of the Polish Ukraine

Goal. Study of the biological stability of different varieties of black currant against currant bud mite and determination of its number. Methods. The assessment of resistance was carried out in response to signs of damaging bud spherical in shape, resembling a method of histological cut of the bud. Determination of the population of each species of currant mite was conducted on a scale of 9 points in the conditions of the Eexperimental field of Zhytomyr National Agroecological University. Results. As a result of the research, it was found that the Titania variety is more resistant to the renal mite, and therefore, the total population density versus the standard variety is 1.46 units. The investigated varieties of black currant were conventionally divided into stable, medium-stable and unstable. By Medium-resistant include varieties Chernech and Vorskla’s Daughter, the coefficient of their population is from 0.80—0.86 units. Compared with the variat of standard, the Amethyst variety was unstable to the tick, the total coefficient of its population was close to 2.0 units. Comparing the results of histological sections of the buds of each varietie, the number of mites in comparison with the variet of standard was from 720 to 1786 units./ bud. In the course of studies on the biological resistance of different varieties of black currant to cinnamon bud mite, it was found that the varieties studied in the experiment are not persistent. Conclusions. The highest density was detected on an unstable Amethyst variety — 1340 specimens/bud, which exceeds the economic threshold of harm and leads to the need for appropriate protection. Taking into account resistant varieties of black currant against cinnabar bud mite, we have developed a biologized defense system. It contributes to limiting the migration of larvae of travelers in the formation of the fetuses, regulates the size of the population, increases the resistance of plants, and is the most important element of intensive technology of raising berries with a high level of payback and competitiveness.