BIOLOGICAL RESISTANCE OF BLACKCURRANT VARIETIES TO SPIDER MITE (TETRANYCHUS URTICAE)

The introduction of new resistant varieties is an important preventive measure in the system of blackcurrant protection against sucking phytophags. In the course of investigation we made the estimation of 8 blackcurrant varieties as for their resistance to the spider mite. The results showed that the pest colonization ratio ranged from 0.26 to 1.15 units, the berry yield of resistant varieties as compared with non-resistant standard varieties made from 2.3 to 3.1 t/ha, the yield of half-resistant ones made 1.3-1.7 t/ha. Net energy made 3605,6 MJ/ha and net income ranged from 64101 to 73881 thousand hrn. under profitability from 448 to 470%