M. Khalili Mahani, H. Seyedoleslami, B. Hatami,
Volume 8, Issue 3 (10-2004)
Abstract
Elm leaf beetle, Xanthogaleruca luteola (Müller), life and fertility tables were investigated under laboratory conditions (25±2°C, 70±5%R.H. and 16L: 8D), on Ulmus carpinifolia, U.c.var.umbraculifera, U. glabra var. pendula and Celtis caucasica, in spring and summer. Since the experiments were conducted under controlled conditions, feeding on hosts with different nutritional qualities was considered to be the only cause of mortality. The aim of this study was to determine the susceptible hosts to the pest. The initial population for each life table was 100 first larval instar on 20 cm foliage which continued to the end of adult longevity. For larval and adult feeding, the foliage was replaced regularly. Larval and adult mortality and eggs number per female were recorded on a daily basis. Results showed that the net reproductive rate (R0) and intrinsic rate of increase (rm) were higher on U. carpinifolia than the other hosts in both seasons. The net reproductive rate was less than one on Celtis caucasica in spring and on U. c. var. umbraculifera in summer, which represented the negative population growth on these hosts. Therefore, U. carpinifolia was the most susceptible host to Elm leaf beetle, the other susceptible hosts being U. glabra var. pendula and U. c. var. umbraculifera, in a descending order and Celtis caucasica was the least susceptible one. .
Sh Mimohamadi, H Allahyari, M Nematolahi, A Sabouri, S Zarghami, Sh Khaghani,
Volume 13, Issue 47 (4-2009)
Abstract
The cabbage aphid Brevicoryne brassicae L. is an important pest, which attacks the rape seed and causes economic damage. In this study, effects of four different cultivars of rape seed (Zarfam, Licord, Hyola 401, and SLM046) on biological parameters and intrinsic rate of increase of B. brassicae were studied in laboratory conditions (25±1ºC, 70±10 RH and of 14:10 (L:D) photoperiod). Results showed that maximum nymphal and reproductive period, longevity of insects were found on Licord cultivar. The maximum fecundity of adult aphid was seen on Hyola 401. There was no significant difference between duration of developmental stages, and aphid fecundity on different cultivars. The intrinsic rate of increase was calculated by Wyatt & White method. Estimated intrinsic rate of natural increase of aphid was 0.316, 0.294, 0.311, and 0.289 on Zarfam, Licord, Hyola 401, and SLM046, respectively. Although the lowest intrinsic rate of increase was observed on Zarfam, statistical analysis of Wyatt & White output showed there was not any significance difference between rm on different cultivars.
