E. Riahi - Department of Plant Protection, Faculty of Agriculture, Shahid Chamran University, Ahvaz, Islamic Republic of Iran.
P. Shishehbor - Department of Plant Protection, Faculty of Agriculture, University of Shahahrekord, Islamic Republic of Iran.
A. R. Nemati - Department of Plant Protection, Faculty of Agriculture, University of Shahahrekord, Islamic Republic of Iran.
Z. Saeidi - Department of Plant Protection, Faculty of Agriculture, University of Shahahrekord, Islamic Republic of Iran.

Development, reproduction and life table parameters of Tetranychus urticae Koch were determined on leaves of peach (G. H. Hale cultivar) at different temperatures, ranging from ۱۳ to ۳۳°C under laboratory conditions. No development was observed at ۱۳°C. Egg-to-adult developmental time decreased gradually from ۱۷ to ۲۷°C and increased at higher temperatures (۲۷ to ۳۳°C). An average of ۱۳۶.۴۳ degree-days was required to complete development above the lower threshold temperature (۱۳.۷۹°C). Mean total egg productions per female were ۴۰.۰۹, ۱۸.۷۴, ۸.۰۳ and ۲۱.۳۳ at ۲۵, ۲۷, ۳۰ and ۳۳ °C, respectively. Mean longevities of the females were ۱۲.۹۱±۱.۶۵, ۵.۹۲±۰.۵۵, ۳.۵۶±۰.۵۴ and ۶.۵۳±۰.۵۶ days, respectively at the above mentioned temperatures. The intrinsic rate of increase (rm) at different temperatures ranged from ۰.۱۰۸ to ۰.۲۱۳ day -۱, with the highest value recorded at ۲۷ °C. The highest and the lowest values of the net reproductive rate (R۰) were obtained at ۲۵°C (۱۶.۸۷) and ۳۰°C (۴.۱۸), respectively. Doubling time (DT) varied significantly at different temperatures and the shortest and longest values of this period were obtained at ۲۷ and ۳۰°C, respectively. The results suggested that T. urticae was able to develop and reproduce within a wide range of temperatures, and that temperatures from ۲۷- ۳۰°C are the most suitable conditions for the development, survivorship and reproduction of the mite.

development, Life table parameters, Peach, temperature, Tetranychus urticae