Developmental Zero of Tetranychus viennensis ZACHER (Acarina: Tetranychidae) on Deciduous Oak

Abstract

The duration of the developmental period from egg to oviposition in Tetranychus viennensis ZACHER on Quercus mongolica var. grosseserrata (BLUME) was studied under constant temperature conditions at 15, 18, 20, 23 and 25°C. The developmental zero (11.42°C) and the total effective temperature (196.46 day-degrees) were determined based on the equation obtained by the least squares method. The number of generations estimated by the total effective temperature and critical photoperiod was almost the same as the empirical one (4 generations) obtained in the field in 1981.