Sublethal effects of spirotetramat on demographic parameters of two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae)

The two-spotted spider mite Tetranychus urticae Koch(Acari: Tetranychidae) is one of the most important and destructive herbivorous mites in fields and greenhouses, and its control is very important due to the wide range of its hosts.

The sublethal effects of spirotetramat based on leaf dipping method were evaluated on demographic parameters of two-spotted spider mite in the laboratory conditions of 25±1 ºC ,60±5% RH and a photoperiod 16:8 hours (L:D). The obtained data were analyzed based on age-stage two sex life table theory.

All sublethal concentrations caused a significant decrease in oviposition period, total fecundity, longevity and total life span compared to control. Maximum and minimum means of longevity of male and female mite were observed in untreated and LC35 groups. Total fecundity varied from 18.12 (offspring/individual) in treatment with 35% sublethal to 57.71(offspring/individual) in control. The lowest net reproductive rate (R0 (was estimated at 11.95 (offspring/individual) at the highest experimental dose. The intrinsic rate of population increase (rm) was recorded as 0.22 offspring/individual/day in control and 0.17 offspring/individual/day in LC35 treatments, respectively. Mean generation time (T) was not significantly affected by different tested doses.

The results of this study demonstrated that sublethal dosage (LC35) of spirotetramat was effective against two-spotted spider mites