ABSTRACT: The brown mite, Bryobia rubrioculus(Acari: Tetranychidae), is a serious pest in orchards in Iran. Laboratory experi-ments were preformed in growth chambers at eight constant temperatures (15, 17.5, 20, 22.5, 25, 27.5, 30 and 32.5ºC), 60 ± 5% RH and a photoperiod of 16:8 h. (Light: Dark) using the sweet cherry leaves (Prunus avium). The survival rate (l x ) was the highest at 15ºC and lowest at 32.5ºC. The life expectancies (e x ) of 1-day adults were determined 38.28 to 11.51 at 15 to 32.5ºC, respectively. There were significant differences between demographic parameters of B. rubrioculusat various temperatures. Net reproduction rate (R0 ), generation time (tG) and intrinsic rate of increase (r m ) ranged from 5.83, 42.79 and 0.041 at 15ºC to 0.67, 24.15 and 0.025 at 32.5ºC. The gross fertility (4.4 eggs) was recorded at 32.5ºC, and the highest (29.5eggs) was at 20ºC. 20ºC is the optimal temperature for B. rubrioculus population growth.
