Effect of flufenzine on population growth of Tetranychus urticae Koch (Acari: Tetranychidae)

Abstract

Effect of flufenzine on different parameters of Tetranychus urticae Koch population growth was investigated. The parameters were computed based on the life tables of female survivors of treatment at different development stages (egg, larva, protonymph, deutonymph) with acaricide concentrations that had caused >90% mortality. The intrinsic rates of increase acquired by the so-called jackknife procedure (rj) from female treatment survovors at egg (rj = 0.237) and larva (rj = 0.220) stages had no significant statistical difference from the corresponding values in control (rj = 0.230). Female survovors of treatment at protonymph or deutonymph stages had 2.1 and 4.5 times lower net reproductive rate (R0) against the control while the corresponding rj values in treatment (0.204 and 0.171) were statistically significantly lower than the control (0.255). Treatment with flufenzine at protonymph and deutonymph stages significantly disturbed the age structure of the surviving part of population. The article discusses the significance of sublethal effects of flufenzine in advancement of the acaricide's application strategy in controlling T. urticae.