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

Document Type : Original research articles

Authors

1 Dept. of Zoology and Agric. Nematology, Fac. Of Agric., Cairo Univ., Giza, Egypt

2 Plant Protection Research. Institute , ARC., Giza, Egypt

Abstract

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.

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