Comparative biology and fertility life tables of Tetranychus urticae Koch (Acari: Tetranychidae) on different common bean cultivars

Abstract

The quality of the host plant affects the development and survival of two-spotted spider mite (TSSM) Tetranychus urticae Koch. The biology and fertility life tables of T. urticae on six cultivars of common bean (Phaseolus vulgaris L.) (chiti Khomein, chiti Ks21189, red Akhtar, red Ks31169, white Pak and white G11867) were studied at constant laboratory conditions (27 ± 2°C, 70 ± 5% relative humidity and 16L:8D h). Immature developmental times of male and female mites were significantly influenced by bean cultivars. This time was significantly longer on white Pak and white G11867 than on the other cultivars, whereas total fecundity per female was higher on red Akhtar than the other cultivars. There were significant differences among the forms of the survival curves of mites on the bean cultivars. Statistical comparisons of the jackknifed intrinsic rate of natural increase (rm ), net reproductive rate (R 0), generation time (T), doubling time (DT) and finite rate of increase (λ) suggest unsuitability of the cultivars white Pak and white G11867 as hosts for the development of TSSM. rm , R 0 and λ of the T. urticae had the highest value on red Akhtar and the lowest on white Pak and T and DT varied significantly on different cultivars and the shortest and longest values were obtained on red Akhtar and white Pak, respectively. The lower population rate of the mite could be the result of antibiotic resistance in the cultivars white Pak and white G11867.