Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box 14115-336, Tehran, Iran
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 25 ± 1°C, 60 ± 5% R.H. and a photoperiod of 16:8 (L:D) hours. The results revealed that the TSSM gross hatch rate varied from 59% on Bandar-Abbas to 83% on Dezful. The gross fecundity rate was 59.726, 31.430, 31.443, 14.461, 19.328, 16.035 and 20.560 eggs/female and the net fecundity rate was 25.804, 17.496, 15.139, 7.620, 5.931, 7.526 and 11.947 eggs/female on the above-mentioned cultivars, respectively. The highest and lowest value of the net fertility rate was 20.735 eggs/female on Isfahan and 3.495 eggs/female on Bandar-Abbas, respectively. Also, the gross fertility rate was the highest on Isfahan (47.994 eggs/female) and the lowest on Bandar-Abbas (11.390 eggs/female). The values of the mean eggs per day varied from 2.040 to 6.560 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 7.550, 8.380, 5.820, 4.850, 5.440, 5.330 and 3.950 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.