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

Abstract

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 o bserved 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 t o complete development above the lower threshold temp erature (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 ( r m ) 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 rep roductive rate ( R 0 ) 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 ran ge of temperatures, and that temperatures from 27- 30°C are the most suitable con ditions for the development, survivorship and reproduction of the mite. Keywords : Development, Life table parameters, Peach, Temper ature, Tetranychus urticae .