Abstract

> Demographic toxicology based on life table analysis is suggested as the best way to study the effects of toxicants. In this study, the effects of the two acaricides, fenpyroximate , propargite, and their mixture on life history traits and life table parameters of Tetranychus urticae Koch are compared. Female adults were treated with the LC50 concentration. The age-stage, two-sex life table theory was used for data analysis. Life table parameters were calculated using the bootstrap method. Among the tested acaricides, the lowest values of the intrinsic rate of increase (r), finite rate of increase (λ) and net reproductive rate (R0) were seen in treatment with fenpyroximate (0.0913 d-1, 1.0957 d-1 and 2.8875 offspring, respectively) and the highest values belonged to those treated with propargite (0.1174 d-1, 1.1246 d-1 and 4.1861 offspring, respectively). The generation times (T) were 11.4714, 12.1347 and 12.3720 d for mites treated with fenpyroximate, propargite and the mixture, respectively. Treatment with fenpyroximate caused the shortest adult longevity of 2.55 d compared to the 4.19 d of propargite and the 3.96 d of the mixture. Fenpyroximate also led to the lowest mean fecundity of 5.96 offspring compared to propargite (7.15 offspring) and the mixture (8.46 offspring). Population projections revealed the differences in stage structure among treatments.