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 degrees C under laboratory conditions. No development was observed at 13 degrees C. Egg-to-adult developmental time decreased gradually from 17 to 27 degrees C and increased at higher temperatures (27 to 33 degrees C). An average of 136.43 degree-days was required to complete development above the lower threshold temperature (13.79 degrees C). Mean total egg productions per female were 40.09, 18.74, 8.03 and 21.33 at 25, 27, 30 and 33 degrees 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 (r(m)) at different temperatures ranged from 0.108 to 0.213 day(-1), with the highest value recorded at 27 degrees C. The highest and the lowest values of the net reproductive rate (R-0) were obtained at 25 degrees C (16.87) and 30 degrees 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 degrees 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 degrees C are the most suitable conditions for the development, survivorship and reproduction of the mite.