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Abstract
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The two-spotted spider mite (TSSM), Tetranychus urticae Koch is an important pest of strawberries grown in greenhouse, and field grown strawberries also may be infested at high humid condition. In this study, we evaluated the life history and demographic parameters of TSSM on five varieties (Frenzo, Karsin-Berg, Klassica, Pajaro and Ventana) of strawberry. The experiment was conducted at a constant temperature of 25 ± 1°C, 75 ± 5 % RH and a photoperiod of 16:8 h L: D. The data was analyzed based on the age-stage, two-sex life table theory. Egg-to-female adult development was faster on Karsin-Berg and slower on Klassica (17.42 vs. 21.12 days). The oviposition period was longer on Karsin-Berg and shorter on Pajaro (27.00 vs. 17.41 days). Fecundity and female adult longevity TSSM were significantly different among the five varieties of strawberry. Life table provides most comprehensive description on the survival, stage differentiation and reproduction of the population. The intrinsic rate of natural increase varied from 0.1067 to 0.1212 day-1 on five varieties. The mean generation time (T) of TSSM was considerably affected by strawberry varieties. Based on results of the present study, Frenzo is a less favorable variety for the development and reproduction of TSSM. Research on these five strawberry varieties can be used to improve our understanding of the population dynamics of the pest and thereby develop effective pest management programs against T. urticae. The use of resistant and/or partialresistant variety such as introduced variety in the present study may be considered as one of the most important part of an integrated pest management (IPM) strategy.
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