Reproductive performance and life expectancy of Tetranychus urticae (Acari: Tetranychidae) on seven eggplant cultivars

Reproductive performance and life expectancy of the two-spotted spider mite (TSSM), Tetranychus urticae Koch were determined on seven eggplant cultivars (Isfahan, Dezful, Shend-Abad, Neishabour, Bandar-Abbas, Jahrom and Borazjan) at ۲۵ ± ۱°C, ۶۰ ± ۵% R.H. and a photoperiod of ۱۶:۸ (L:D) hours. The results revealed that the TSSM gross hatch rate varied from ۵۹% on Bandar-Abbas to ۸۳% on Dezful. The gross fecundity rate was ۵۹.۷۲۶, ۳۱.۴۳۰, ۳۱.۴۴۳, ۱۴.۴۶۱, ۱۹.۳۲۸, ۱۶.۰۳۵ and ۲۰.۵۶۰ eggs/female and the net fecundity rate was ۲۵.۸۰۴, ۱۷.۴۹۶, ۱۵.۱۳۹, ۷.۶۲۰, ۵.۹۳۱, ۷.۵۲۶ and ۱۱.۹۴۷ eggs/female on the above-mentioned cultivars, respectively. The highest and lowest value of the net fertility rate was ۲۰.۷۳۵ eggs/female on Isfahan and ۳.۴۹۵ eggs/female on Bandar-Abbas, respectively. Also, the gross fertility rate was the highest on Isfahan (۴۷.۹۹۴ eggs/female) and the lowest on Bandar-Abbas (۱۱.۳۹۰ eggs/female). The values of the mean eggs per day varied from ۲.۰۴۰ to ۶.۵۶۰ eggs/female, which was minimum on Neishabour and maximum on Isfahan. The life expectancy of one-day-old adults of the TSSM was estimated to be ۷.۵۵۰, ۸.۳۸۰, ۵.۸۲۰, ۴.۸۵۰, ۵.۴۴۰, ۵.۳۳۰ and ۳.۹۵۰ days on the above-mentioned cultivars, respectively. Comparison of the reproductive parameters of the TSSM on the examined cultivars revealed that Isfahan was the most susceptible cultivar and Neishabour was the most resistant cultivar to this pest. Using resistant host plants is one of the most important components of an integrated pest management program.