POPULATION FLUCTUATION OF Tetranychus urticae (ACARI: TETRANYCHIDAE) IN DIFFERENT CHRYSANTHEMUM VARIETIES IN GREENHOUSES

Abstract

This research aimed at verifying the population fluctuation of the phytophagous spider mite Tetranychus urticae in four chrysanthemum (Chrysanthemum morifolium Ramat: Asteraceae) cultivars: Convington (Yellow - CVT), Kalamazoo (White - KLZ), White diamond (Cream - WD) and Royal Time (Pink - RT). Samples were taken every two weeks during two production cycles (March to April and August to October). In each sampling, leaves from 20 chrysanthemum plants were collected from each cultivar, one apical and one basal (40 leaves/cultivar sample). A total of 583 T. urticae individuals were collected, 41.9 % of the individuals in WD, 38.0 % in KLZ, 15.1 % in RT and 5.0 % in CVT. There were no significant differences in the populational density among the evaluated varieties (p > 0.05). Thus, the results indicated no significant differences in plant susceptibility to the phytophagous mite, suggesting that the four varieties are equally adapted to avoid T. urticae attack.