نشریه نامه انجمن حشره شناسی ایران
سال سی و سوم شماره 4 (پیاپی 55، زمستان 1392)

In this study، mineral oil and kaolin as alternatives to conventional pesticide (diazinon) were evaluated to manage Dubas bug، Ommatissus lybicus de Bergevin، in the field and laboratory. In the field experiment، effect of four treatments was evaluated against population density (first and second nymphal stages) and honeydew production (as main damage) of Dubas bug. A single application of each product was applied at the recommended rates. Results showed that kaolin، mineral oil and diazinon were statistically similar in decreasing the population density and damage of Dubas bug. This result makes kaolin and mineral oil as potential alternatives to conventional insecticides in date palm orchards. In the laboratory، mineral oil was effective on egg mortality. In settling choice test، the ability of Dubas bug to discriminate between kaolin-treated and kaolin-untreated leaflets increased significantly over the time and females laid more eggs on untreated leaflets than kaolin-treated leaflets. Results of no-choice test revealed that the leafhoppers could lay eggs on treated leaflets as many as on untreated leaflets.

An investigation was carried out to study the life history of Aphis nerri Boyer de Fonscolombe on oleander، Nerium oleander L.، under laboratory conditions (RH of 70 ± 5% and a 16:8 (L: D) h photoperiod) based on the age-stage، two-sex life table at 10، 15، 20، 25 and 30 ºC. Duration of total pre-adult stages was 35. 61 ± 0. 833، 19. 6 ± 0. 343، 12. 02 ± 0. 243، 9. 12 ± 0. 182 and 7. 42 ± 0. 115 days at 10، 15، 20، 25 and 30 ºC، respectively. As temperature increased، the developmental time and longevity of the A. nerri shortened. The shortest developmental time (17. 72 ± 0. 244 days) and longevity (10. 3 ± 0. 234 days) were obtained at 30 ºC. With decreasing temperature، age-stage survivorship (lx) extended. Maximum fecundity of females was observed at 25 ºC with 25. 54 ± 0. 76 nymphs per female. The intrinsic rates of increase (r) at these temperatures were 0. 012 ± 0. 0014، 0. 075 ± 0. 0016، 0. 13 ± 0. 001، 0. 23 ± 0. 003 and 0. 24 ± 0. 003 d-1، respectively. The highest net reproductive rate (R0) was at 25 ºC (25. 56 ± 0. 73) and the lowest value was at 10 ºC (2. 58 ± 0. 28). According to our results، 25-30 ºC were the optimum temperature range for A. nerri population growth.

Green lacewing، Chrysoperla carnea (Stephens)، is an important predator of arthropod pests such as aphids، psyllids، thrips and whiteflies. Toxicity of endosulfan، imidacloprid and indoxacarb was assessed on male and female C. carnea in the laboratory. Contact bioassays were carried out in glass Petri dishes. The LC50 values for indoxacarb، imidacloprid and endosulfan were 0. 011، 0. 053، and 0. 343 g AI/L for males، and 0. 019، 0. 098 and 0. 398 g AI/L for females، respectively. Males were more sensitive than females to all three insecticides. To assess the sublethal effects، using IOBC (International Organization for Biological Control) method، adults were treated with LC25 of each insecticide. Analysis of variance did not show significant differences among treatments regarding the developmental time of the first، second and third instars، pupae and sex ratio. Differences between treatments and control were significant regarding pre-oviposition، oviposition and post-oviposition periods، fecundity، fertility، longevity of male and female. Mean longevity for control، imidacloprid، endosulfan and indoxacarb were 30 ± 2. 3، 24. 3 ± 3. 3، 21. 3 ± 2. 4 and 19. 7 ± 1. 4 days for males، and 36. 9 ± 2. 5، 31. 8 ± 2. 9، 27. 7 ± 1. 7 and 26. 7 ± 2. 6 days for females، respectively. The highest and the lowest rates of fecundity were 540 ± 49 and 206 ± 42 in control and indoxacarb، respectively. Based on the IOBC classification method، imidacloprid، endosulfan and indoxacarb were slightly harmful (%30 < Total Effect Index < %79) against adults. The adult stage was very sensitive to indoxacarb، imidacloprid and endosulfan. Hence، these insecticides should not be applied when the density of adults is high in the field.

The eggs and larvae of the Mediterranean flour moth، Ephestia kuehniella (Zell.) are widely used to rear parasitoids and predators for biological control programs. In this study، nutritional responses، proteolytic and digestive amylolytic activities of the fifth instar larvae as well as some biological parameters of E. kuehniella were studied on flour of nine wheat cultivars under laboratory conditions. The longest larval period of the fifth instar was on the cultivars Back cross Roshan and Sepahan and the shortest was on cultivar Tajan. The highest daily and total fecundity was observed on N-86-7. The fifth larval instar reared on Pishtaz showed the highest efficiency of conversion of ingested food. The highest general proteolytic activity was determined on the cultivar N-86-7 and the lowest was on N-80-19. Maximum and minimum digestive amylolytic activity was determined on the cultivars Kuhdasht and Khoshki line 9، respectively. According to the results obtained، Pishtaz and N-86-7 were the most suitable cultivars for laboratory rearing of E. kuehniella as the alternative host to use in the mass production of natural enemies.

In order to study the pollution potential of TiO2 nanoparticles (TiO2-NPs) on ecological health، this research was carried out on the cellular energy allocation (CEA) of Glyphodes pyloalis Walker exposed to TiO2-NPs. The newly ecdysed fifth instar larvae of G. pyloalis were treated with LC10، LC20، LC30، LC40 and LC50 concentrations of TiO2-NPs and the amount of energy available (Ea)، energy consumption (Ec) and cellular energy allocation were compared. The resulting calculated energy reserves (lipid، carbohydrate، glycogen and protein) showed that increasing the time of exposure، the total lipid and carbohydrate amounts significantly decreased، when the LC30، LC40 and LC50 concentrations were applied. The amounts of glycogen in the larvae treated with LC10، LC20 and LC30 concentrations of TiO2-NPs were increased، whereas the LC40 and LC50 concentrations led to decrease in the amount of glycogen. The significant reduction in the amount of total protein compared to the control and over all three days of treatment was observed for LC50 concentration of TiO2-NPs; however، the LC10 concentration lead to a significant increase of the total protein after three days. Ea decreased in a dose-response related manner and over all time points، but it significantly increased in treated larvae by LC10 and LC20 concentrations after two days. Ec increased as concentrations grew to LC30 and then started to decrease. The results showed that CEA was not affected by LC10 concentration، but significantly decreased when the concentration increased and at all time points probably as a cost to deal with TiO2-NPs detoxification. Therefore، it will be possible to use the CEA as an appropriate early biomarker for the impacts of TiO2-NPs.

A new mealybug species، Chorizococcus pazoukii Moghaddam sp. n. is described on the root of an unknown plant from Iran. The new species is taxonomically near to the Iranian species Chorizococcus viticola Kaydan & Kozár but it is distinguished by the oral rim tubular ducts occur in two rows across of dorsum، two sizes of oral rim tubular ducts on both surfaces of the body and the presence of multilocular disc pores on the ventral abdominal segments VI-VIII + IX.

The lethal and sublethal effects of pyriproxyfen (a juvenile hormone analogue) were investigated on feeding deterrence، growth and larval weight as well as enzymatic and non-enzymatic activities of the third instar larvae of elm leaf beetle، Xanthogaleruca luteola Müller. The LC30 and LC50 values were estimated to be 133 and 343 ppm per larvae after 72 hours، respectively. Due to the treatment with 133 and 343 ppm of pyriproxyfen، feeding deterrence and prolongation in larval duration were observed. Also، the amounts of total protein، glucose، glycogen، urea، acid phosphatase and α-amylase activities were significantly decreased in the treated specimens compared with the controls. On the other hand، alanine aminotransferase activity and cholesterol levels were increased in the specimens 72 hours after the treatment compared with the controls. There were significant differences in the amount of uric acid and the activity of alkaline phosphatase، glutathione S-transferase and esterases compared with the controls. Present results showed that pyriproxyfen caused some biological and physiological discrepancies in the survived insects after treating with LC50 concentration of the insecticide which indicates changes in the metabolism of these compounds. Hence، it seems that pyriproxyfen has the potential to be used as a biorational insecticide in the integrated pest management (IPM) program for X. luteolla.