Resistance of Two Eggplant Cultivars Against the Two-Spotted Spider Mite; Tetranychus urticae Koch Infestation, with Notes on its Biology

Field and laboratory studies revealed that the eggplant Black baity cultivar recorded the highly significant susceptible to infestation with Tetranychus urticae Koch compared with Baity cultivar. Susceptibility of eggplant cultivars to infestation may be affected by plant leaf morphological structure; length, thickness and density of leaf trichomes. Average number of trichomes /mm2 leaf was 2l .l and 21.6 for Baity and Black baity cultivars, respectively. The highest mean number of T. urticae movable stages on leaves of Black baity cultivar was associated with higher 1eve1s of total amino acids and total carbohydrates and with the lowest leve1s of total phenolic compounds and tannins. Durations of egg, different immature stages, life cycle and life span of T. urticae female were the shortest when reared on leaves of Black baity cultivar and the longest on leaves of Baity cultivar. The two eggplant cultivars affected the life table parameters of T. urticae. The shortest mean generation time (T) was 12.08 days on Black baity cultivar, and the longest was 13.21days on Baity cultivar. The highest net reproductive rate (Ro) was 32.01 females/female cm Black baity cultivar, and the lowest was 21.13 females/female on Baity cultivar.