Asian Journal of Research and Review in Agriculture

According to the importance of Plutella xylostella L. (Lepidoptera: Plutellidae) control and the obligation use of insecticide, it must do extensive studies and searches on the effect of insecticides on the biology of this important Brassica crop pest. Then life table is the suitable ways to measure these effects. In these study three strains of P. xylostella were used, the original collection of larvae were from kalubia governorate, it reared to 4 months without insecticide exposure was called the unselected and the selected for 4 months by sublethal dose of teflubenzuron called the selected population. Firstly, LC₅₀ values for kalubia was 1.79 ppm refers to the population susceptibility levels for this insecticide that decline to 1.6 ppm in the unselectred, and rises to 2.2, 2.9 and 4 ppm for the selected strain three generation respectively. Resistance ratio between selected and unselected refers to the development of resistance in the strain toward this pesticide. Fertility Life table results refer to that the P.xylostella rearing under teflubenzuron insecticide selection pressure, briefly, the relative fitness that decline after selection of kalubia population from 1.4 to 0.64. The Net reproductive rate, R₀ and the mean generation time was 1.7, 2.4 and 3.75, 17, and 19.18, 17.4 days for kalubia, selected and unselected strain respectively. The same arrangement, the finite rate of increase (λ) was 1.032, 0.047 and 1.079; also the doubling days was 22.08, 15.1 and 9.13 days respectively. Likewise, the intrinsic rate of increase (rm) was 0.0314.0.046 and 0.076 for the same arrangement respectively. In addition remarks, low larval survival rate, longer larval and pupae duration, and longer development time, low emergence rate, also fecundity and hatchability compared with unselected strain, and the life span were detected.