DEMOGRAPHIC PARAMETERS OF TETRANYCHUS URTICAE (ACARI: TETRANYCHIDAE) ON FOUR ROSA SP CULTIVARS

The goal of this work was to determine the life parameters of Tetranychus urticae Koch on leaves of 4 rose (Rosa sp.) cultivars. To conduct this experiment a colony of T urticae collected from ornamentals grown at Saltillo, Coahuila, Mexico, was established on bean (Phaseouls vulgaris L.) seedlings inside a Biotronette chamber at 25 +/- 2 degrees C, 60-70 RH and 12:12 h L:D. According to the experimental design, 100 one-day old recently mated and fertilized females were transferred to 2.5 cm diam rose (Rosa sp. L.) leaf discs from 'Emma', 'Luna', 'Gran Gala' and 'Virginia' cultivars in such a way that every experimental unit included 1 female per disc. The latter were maintained at the above temperature, RH and photoperiod conditions. Demographic parameters in this experiment showed greater growth potential of this pest on the 'Luna' and 'Gran Gala' cultivars than on 'Virginia' and 'Emma'.