Temperature Effects on Development and Life Table Parameters of Tetranychus urticae (Acari: Tetranychidae)

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 13 to 33°c under laboratory conditions. no development was observed at 13°c.egg-to-adult developmental time decreased gradually from 17 to 27°c and increased at higher temperatures (27 to 33°c). an average of 136.43 degree-days was required to complete development above the lower threshold temperature (13.79°c). mean total egg productions per female were 40.09, 18.74, 8.03 and 21.33 at 25, 27, 30 and 33 °c,respectively. mean longevities of the females were 12.91±1.65, 5.92±0.55, 3.56±0.54 and 6.53±0.56 days, respectively at the above mentioned temperatures. the intrinsic rate of increase (rm) at different temperatures ranged from 0.108 to 0.213 day ^-1, with the highest value recorded at 27 °c. the highest and the lowest values of the net reproductive rate(r0) were obtained at 25°c (16.87) and 30°c (4.18), respectively. doubling time (dt) varied significantly at different temperatures and the shortest and longest values of this period were obtained at 27 and 30°c, respectively. the results suggested that t. urticae was able to develop and reproduce within a wide range of temperatures, and that temperatures from 27- 30°c are the most suitable conditions for the development, survivorship and reproduction of the mite.