n. memarizadeh

The white peach scale, Pseudaulacaspis pentagona, is one of the most important pests of stone fruit trees in the northern provinces of Iran. The efficacy of several synthetic and biorational insecticides was investigated on white peach scale in a peach orchard in Shirang-E-Olya village of Kamalan district in Aliabad-E-Katoul city. The study was conducted in a randomized complete block design with 9 treatments and four replications in the peach orchard. Treatments in this experiment include: Pyriproxyfen (EC10%) at the rate of 1 and 2 ml/L, Chlorpyrifos (EC 40.8%) at the rate of 4 and 8 ml/L, Thiacloprid (OD 24%) at the rate of 0.6 and 1.2 ml/L, Spirotetramate (SC 100) at the rate of 1 and 2 ml/L, Flupyradifurone (SL 20%) at the rate of 1 and 2 ml/L, Palizin (SL) at the rate of 3 and 1.5 ml/L, Tondexir (EC) at the rate of 4 and 8 ml/L, Citral (EC) at the rate of 1 and 2 ml/L and control. Sampling was performed 1 day before spraying, and then the first and second generation of this pest after spraying. Data were analyzed by Glm method and means were compared by Duncan multiple range test using SAS software. Spirotetramate (1 ml/L) had the highest efficacy percentage among the insecticides used on the first generation of this pest. For the second generation also, the highest efficacy was observed by Spirotetramate (1ml/L) and Chlorpyrifos (4 ml/L). Among the bio-insecticides, 1.5 ml/L of Palizin and 8 ml/L of Tondexir were highly effective, too. Although chemical insecticide such as Chlorpyrifos showed good results, the new insecticide Spirotetramate had the same or better efficacy than Chlorpyrifos. Therefore this insecticide can be a suitable substituted for chlorpyrifos. Biorational insecticides also had good effect in eliminating white peach scale and can be used as biocompatible insecticide.

The activity of general esterases (ESTs), catalase (CAT) and glutathione S-transferase (GST) were used to survey the in vivo responses of Glyphodes pyloalis Walker to bare carbon nanotubes (CNTs) and synthesized carbon nanotubes/titanium dioxide nanoparticles (CNTs/TiO2-NPs). These biochemical tests were performed in the three time points of exposure (i.e. 24, 48 and 72 h) and to five concentrations (i.e. 100, 200, 300, 400 and 500 ppm). Results showed that the enhancement of treated concentrations of both CNTsand CNTs/TiO2-NPs irreversibly impaired ESTs activities when α- naphthyl acetate (α-NA) used as a substrate. Using β-naphthyl acetate (β-NA) as a substrate, inhibitory effect of both CNTs and CNTs/TiO2-NPs on ESTs activities was more intense than that of α-NA. Results also demonstrated that inhibition of GST activities generating by bare CNTs and also by CNTs/TiO2-NPs was dependent to the concentrations of treatments. CAT assays showed that the increasing CNTs concentrations over exposure time could be affected by enhancement of the CAT activities in G. pyloalis. In the similar manner to bare CNTs, the increasing CNTs when coupled to TiO2-NPs (CNTs/TiO2-NPs) over exposure time could be interfered to the CAT activities. It can be concluded that these tested enzymes are good early biochemical indicators in order to prediction and management of adverse effects of bare CNTs and also CNTs when coupled to TiO2-NPs on insects.