Fitness of Tetranychus urticae Koch (Acari: Tetranychidae) on Three Strawberry Varieties: Biology and Fertility Life-Tables

Abstract

The two-spotted spider mite, Tetranychus urticae Koch, is one of the most important pests of strawberry crops. The use of comparatively resistant crop cultivars or varieties may limit the negative effects of this pest; we tend to thus compared population growth parameters of T. urticae reared on three strawberry varieties: RU-1, RU-2 and RU-3. The life table parameters were estimated at 25 ± 1 o C, 60 ± 10 % RH, and a photoperiod of 16:8 h (L: D). The average developmental time from egg to female adult on the varieties was 11.70 ± 1.23, 12.60 ± 0.91 and 12.77 ± 0.92, respectively. The lifetime fecundities were 57.38 ± 3.67, 56.57 ± 4.42 and 63.90 ± 4.33 eggs/female for RU-1, RU-2 and RU-3, respectively. RU-2 was the most suitable host for T. urticae with rm = 0.172 (offspring/female/day), followed by RU-3 (0.170). The slowest population growth was observed on the RU-1 variety with rm = 0.167. These findings indicate that the selection of strawberry variety will affect how fast spider mite populations reach destructive levels during a culture.