تاثیر فتوپریود بر رشد و نمو و پارامترهای دموگرافی کنه تارتن دولکه‏ ای Tetranychus urticae (Acari: Tetranychidae)

The two-spotted spider mite Tetranychus urticae (Koch) is one of the most serious pests in the greenhouse crops. As growth and reproduction can be affected by the photoperiod, effects of five photoperiods at 16:8 (control), 14:10, 12:12, 10:14 and 8:16 (L: D) hours were investigated on growth and reproduction of this pest under laboratory conditions 50% RH and 25 ˚C. Development time of almost all immature stages was higher (9.277 ± 0.167 days) at the photoperiod of 12 h daylight than the control (8.538 ± 0.150 days). At the photoperiod of 12 h daylight, female adults had the shortest fecundity (44.705 ± 8.905 egg/female) and oviposition days (7 ± 0.887 days) and the control (116.1 ± 13.025 egg/female, 11.793 ± 1.170 days) the highest rate. The longevity of females was significantly affected by a photoperiod of 12 h daylight that was 7.941 ± 1.085 days, shorter than the control (14.266 ± 1.408 days). The lowest values of the intrinsic rate of increase (rm = 0.186 ± 1.938) and net reproductive rate (R0 = 15.51 ± 4.29) were obtained at the photoperiod of 12 h daylight and 12 darkness and the highest ones at the control (rm = 0.284 ± 1.122, R0 = 69.66 ± 11.20). Three other photoperiods had no significant difference with the control. Due to the fact that the photoperiod of 12:12 is considered as a critical photoperiod for induction of diapause of this pest, the results of this study indicated that this regime under non-diapausing conditions (25 ˚C) has remarkable effects on reduction of growth and life table parameters of this pest.