|
Abstract
|
The current survey was carried out to evaluate the effect of different nitrogen levels (0, 2.1, 3.0, 3.9 g ∙ pot–1 nitrogen as urea 46%) on tomato fruit worm Helicoverpa armigera on six common tomato cultivars (e.g., Kingston, Riogrand, Earlyurbana, Redston, Superstrain-B and Primoearly) under laboratory conditions [25 ± 1°C, 60 ± 5% RH, 16 : 8 (L : D) h]. The mortality, developmental period of immature stages as well as the longevity and fecundity of adult stages were recorded. Data were analyzed based on the age-stage, two-sex life-table theory. The longest (24.21 ± 0.59 days) larval developmental period was recorded in the Earlyurbana variety with zero nitrogen level and the shortest (15.44 ± 0.36 days) in Superstrain-B variety with the highest nitrogen level. Consequently, the net reproductive rate (R0) ranged from 35.7 ± 7.06 to 62.16 ± 18.9 offspring/female/individual in the Redston variety with zero nitrogen level and in the Superstrain-B variety with the highest nitrogen level, respectively. The lowest and highest values of the intrinsic rate (r) and finite rate of increase (l) were estimated for the Redston variety with zero level of nitrogen (0.0712 ± 0.0065 and 1.0732 ± 0.0069 day–1) and the Superstrain-B variety with the highest nitrogen fertilizer (0.1507 ± 0.0057 and 1.1629 ± 0.0066 day–1), respectively. The results demonstrated that nitrogen fertilizer influenced nearly all the life parameters of the pest which depended on the cultivars. Finally, it could be concluded that Kingston and Superstrain-B were suitable and Earlyurbana and Redston were unsuitable host plant cultivars for H. armigera.
|