Biological and reproductive parameters of Tetranychus urticae (Acari: Tetranychidae) on commercial important cotton cultivars

The two-spotted spider mite, Tetranychus urticae Koch, is one of the major pests with a wide host range in the world. Host plants and plant varieties could be a factor influencing the biological and reproductive properties of pests. The effect of 12 cotton commercial cultivars, including Avangard, B557, Belli isovas, Chegvara, Khordad, 010, Opal, Sahel, Shirpan 539, Tashkand, Varamin and Varamin349 on biological and reproductive parameters of T. urticae was investigated under laboratory conditions, 25±1°C, 65±5% RH, and photoperiod of 16:8 (L:D) hour. The longest female immature period was observed on 010 (13.70 days) and the shortest period was on Khordad cultivar (10.06 days). The longest and shortest female adult longevities were on Shirpan539 (18.70 days) and Opal (9.30 days), respectively. The life expectancy of one-day-old adult of two-spotted spider mite was estimated to be 13.30, 11.95, 12.45, 16.30, 16.80, 8.45, 8.17, 12.85, 17.82, 10.41, 11.10 and 18.20 days on the respected cultivars. The net fecundity rate was 33.96, 39.64, 41.70, 50.09, 49.09, 11.21, 5.19, 43.07, 41.47, 6.69, 14.62, and 82.03 eggs/female on the above-mentioned cultivars, respectively. Moreover, the highest and lowest values of the net fecundity rate was on Belli isovas (83.45 eggs /female) and Opal (5.81 eggs/female), respectively. Comparison of the achieved results on the tested cotton cultivars revealed that Varamin349 is the susceptible cultivar and the Opal cultivar is a relative resistant cultivar against T. urticae. These findings could be considered in planning of an integrated pest management program of this mite.