List of Articles Tetranychidae

• Open Access Article
  • Abstract Page
  • Full-Text
  
  1 - Effect of two cotton cultivars on population fluctuations of spider mites (Acari : Tetranychidae)
  Seyed Hamid Reza Forghani Hadi Ostovan Javad Shaterian Nazila Honarparvar
  Cotton plant, Gossypium hirsutum L., is one of the most economic crop around the world and in GonbadKavous (located in North of Iran) is an important cotton cropping region. The spider mites (Tetranychus spp., Acari: Tetranychidae) are the most damaging pests on the fie More

  Cotton plant, Gossypium hirsutum L., is one of the most economic crop around the world and in GonbadKavous (located in North of Iran) is an important cotton cropping region. The spider mites (Tetranychus spp., Acari: Tetranychidae) are the most damaging pests on the field crops. Use of resistant cultivar is one of the foremost accepted chemical-free techniques for controlling this pest. A two year study was conducted to evaluate resistance of two most-cultivated cultivars, sahel and siokra, against spider mites. The results showed that there was a significant difference in population of spider mites, so that the population on Sahel was more than Siokra for two years studied. The separate population figures for each year recorded 10.3 ± 0.6 eggs and 24.2 ± 1.3 mites on Sahel, 7.4 ± 0.4 eggs and 15.9 ± 0.9 mites on Siokra in first year whereas it was 22.6 ± 2.1 eggs and 35.2 ± 2.6 mites and also 8.6 ± 0.5 eggs and 16.9 ± 1.1 mites in second year for them. Mite’s populations increased from mid-season to the end of growing period. The results showed that effects of ambient temperatures on egg populations and number of active stages of mites was more favorable on Sahel compared with Siokra. Population assessment of mites on these two cultivars can be used in management of the pest.  Manuscript profile
• Open Access Article
  • Abstract Page
  • Full-Text
  
  2 - Effect of solitary and group rearing on demographic parameters of Stethorus gilvifrons (Col.: Coccinelidae) feeding on Tetranychus urticae
  H. Ranjbar Aghdam M. Jafari A. A. Zamani Sh. Goldasteh E. Soleyman-nejadian
  Stethorus gilvifrons is one of the most important monophagus predators of Tetranychus urticae. In this study, demographic parameters of S. gilvifrons were compared between solitary and group (5 pairs of the predator) rearing systems feeding on different developmental st More

  Stethorus gilvifrons is one of the most important monophagus predators of Tetranychus urticae. In this study, demographic parameters of S. gilvifrons were compared between solitary and group (5 pairs of the predator) rearing systems feeding on different developmental stage of T. uricae at 27±1°C temperature, 60±10% RH and a photoperiod of 16:8 h. L:D. In order to start experiments, 120 eggs (< 24 h. old) were selected randomly from the laboratory culture of S. gilvifrons for each treatment. The data were analyzed based on the age-stage, two-sex life table theory. Developmental times of the incubation period, larval, pupal, and total immature stages of S. gilvifrons were 3.92±0.08, 6.52±0.14, 2.98±0.06, 13.59±0.14 days, respectively, in solitary rearing system. In the case of group rearing, developmental time of S. gilvifrons for the mentioned developmental stages were 3.51±0.06, 6.85±0.21, 2.85±0.11, and 13.18±0.21 days, respectively. Moreover, estimated values of intrinsic rate of increase (r), finite rate of increase (λ), mean generation times (T), net reproductive rate (R0) and Gross reproduction rate (GRR) were (0.1219; 0.1455 day-1), (1.1297; 1.1567 day-1), (30.23; 19.88 day-1), (39.92; 18.08 offspring/individual), (265.38; 88.37 females/female/generation), respectively in solitary and group rearing systems. According to the obtained results, demographic parameters of the S. gilvifrons were affected by the number of the individuals in the arena, and population growth was less in the group rearing system, in comparison with solitary rearing condition. These findings can be useful for improving mass rearing of S. gilvifrons and biological control programs of Tetranychids. Manuscript profile