Life history of hawthorn spider mite Amphitetranychus viennensis (Acarina : Tetranychidae) on various apple cultivars and at different temperatures

Development duration and reproduction rate of hawthorn spider mite Amphitetranychus viennensis (Zacher) were carried out on five different apple cultivars (Amasya ( local cultivar), Golden Delicious, Granny Smith, Starking Delicious and Starkrimson Delicious) at 25 degreesC, 65 +/- 10 % RH and 16: 8 L: D. In addition, the same parameters were determined on Golden Delicious leaves at three constant temperatures (20, 30 and 35 degreesC, 65 +/- 10% RH and 16: 8 L: D) in the laboratory. A. viennensis showed a better performance on Golden Delicious than on the other apple cultivars. This was mainly due to a short development time (10.7 days), high daily egg production (5.2 eggs/female/day) and early reproduction peak. The highest intrinsic rate of natural increase (r(m)) was determined on the variety Golden Delicious (r(m) = 0.247/day), while the lowest one was observed on the variety Starking Delicious (r(m) = 0.215/day). The developmental periods of A. viennensis varied from 7.4 to 18.8 days at 35 and 20 degreesC for females, while it varied from 7.9 to 17.2 days at 30 and 20 degreesC for males. The development threshold of the eggs and pre-adult stages were 9.72 and 9.07 degreesC, total effective temperature was 72.99 and 185.18 degree days, respectively. The mean generation time (T-o) of the population ranged from 16.13 days at 30 degreesC to 29.15 days at 20 degreesC. The net reproductive rate (R-0) increased from 54.33 female/female at 20 degreesC to 78.34 female/female at 25 degreesC, and decreased to 75.71 female/female at 30 degreesC. The highest intrinsic rate of increase (r(m)) was reached at 30 degreesC (r(m) = 0.268/day), the lowest one at 20 degreesC (r(m) = 0.136/day).