فهرست مطالب babak zahiri

Breeding and use of resistant tomato varieties agaist  two-spotted spider mite, which is one of its critical pests in farms and greenhouses, require adequate knowledge of the effective factors of the crop in reducing the fitness of the pest as well as realizing the plant’s ability to mitigate the herbivore injury. Therefore, the host recognition and host acceptance of the mite and the host suitability of the plant and its responses to mite injury were assessed in laboratory by evaluating the behavioral and physiological responses of the mite and by measuring the physical and chemical characteristics of ten tomato varieties. Results showed that the mite colonization by using a free-choice test and the oviposition rate and  the population growth of the mite by using a no-choice test were significantly different on tomato varieties, indicating some degrees of antixenosis and antibiosis resistance mechanisms especially in Super-Luna and Super-Urbana varieties which also had higher densities of type IV and VI glandular trichomes. Phenol concentration were increased significantly after being injured by the mites in Cal-JN3, and Super-Urbana varieties and it showed significant negative correlations with mite densities. Varieties Cal-JN3, Super-Luna, Super-Urbana and Comodoro were placed in the resistant group, Super-Chief, Mobil-Royal, Queen-2274, and Primo-Early inside the intermediate group and Chef-Falat and Firenze in the sensitive group.

Plant hormones are the compounds that are increased followed by the attack of herbivores to enhance plant defense ability. The idea of external application of hormones on crop plants to induce resistance to herbivores has been studied by examining the behavioral and physiological responses of tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae) on three tomato cultivars including Dehghan, Falat-111 and Mobil in response to jasmonic acid and salicylic acid hormone treatments by measuring the oviposition preference of the females, survivorship and development time of each immature stage and the concentration of soluble carbohydrates and phenols in the leaves. Oviposition preference of females and embryo development time on the susceptible cultivar, Falat-111, were significantly reduced and increased respectively in jasmonic acid treatment units. Larval development rate showed the highest response to hormonal treatments in the semi-resistant cultivar, Dehghan. Survivorship and development rates of the pupae were also significantly reduced under the influence of jasmonic acid treatments on all three cultivars. Despite significant differences in leaf soluble carbohydrates and phenols concentrations between control and sprayed tomato cultivars as well as a significant positive correlation between changes in carbohydrates and phenols concentrations in the experimental units, no significant correlation was observed between the aforementioned plant contents and insect biological variables. The results showed that these hormones in combination with appropriate plant varieties can be used to induce behavioral and physiological changes in the pest.

Macrosiphum rosae is one of the most important members of the Aphididae (Hemiptera) which feeds on plant juices, colonizes underside of leaves,stems and buds. This pest is a polyphagous insect vastly found in Europe, Asia and America. Coccinella septempunctata (L.) (Col: Coccinellidae) is the successful biological control agent against aphids in under the greenhouse and field conditions. In the present study, the effects of constant temperature on the demography of C. septempunctata which feds on M. rosae was investigated.
The predators were originally collected from the field (Sorke hesar park in Tehran) in march 2012 and reared on aphids in the germinator at 25 ± 1°C, 60 % ± 5 % relative humidity and photoperiod of 16L: 8D/h to lay their eggs and then females were removed after oviposition. These eggs were used for further examination. The life table parameters of C. septempunctata were measured under laboratory conditions at constant temperatures (14, 25 and 31) °C, relative humidity 60 ± 5 % and photoperiod of 16 hours light and 8 hours darkness with 100 repetitions. The different stages of the ladybeetles were fed with 20-100 aphids from different stages of M. rosae. The developmental time of immature stages of beetles were recorded every day. When adult females emerged, an adult male was introduced into the cells to fertilize of them and after that number of offspring produced was counted daily. SAS software v 9.1 was used for data analysis. One-way ANOVA was run to determine the significant differences between demographic parameter of C. septempunctata at two constant temperatures. If there were significant differences, the Tukey's multiple tests were used for multiple comparisons (P There was no ovipostion at 14 °C. The intrinsic rate of increase (rm) of C. septempunctata at 25 and 31 ˚C were 0.170 and 0.186, the net reproductive rate (R0) were 187.55 and 76.74,the finit rate of increase were 1/18 and 1/20 and the mean generation time (T) of ladybird were 30.78 and 23.32 days, respectively. The lifetime oviposition and mean ovipositon rate were highest at 25 °C and lowest at 14 °C. The average total fecundities of C. septempunctata at 25 and 31 °C were 307.46 and 125.8 (eggs / femal). The average of adultʼs survival rate at three studied temperatures was analyzed by Weibull model. The maximum of life expectancy rate is at 14 °C and the minimum rate is related to 31 °C. Considering the high value of rm obtained from lifetime table of C. septempunctata in 25°C and 31°C, it can be concluded that the reproduction rate of this variety is at a high level. Among the three studied temperatures, in 31°C, the beetle had the highest intrinsic rate of natural increase and the maximum rate of fertility calculated in 25°C.
Considering that the rose bush is on the main vegetation in the urban area and M. rasae is rose̕ s main pest, high amount of pesticides are used for fighting this pest in the parks and in planted areas each year. In addition to removing natural enemies, these poisons cause environmental pollution and pose hazardes for the citizens who are directly exposed to this pollution. The higher values of rm in comparison to values calculated in studies of the other researchers with similar temperatures, shows the appropriate feeding value of this predator for C. septempunctata. thus, application of biological control, supporting natural enemies of pests and breeding and releasing of fruit full insects like C. septempunctata, are the alternative ways to using poisons and pesticides.

The life history of Bryobia rubrioculus Scheuten (Acari: Tetranychidae) on sour cherry leaves was studied based on the age-stage, two-sex life table at nine constant temperatures (15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5 and 33.5 ºC), 60 ± 5% RH and a photoperiod of 16: 8 (L: D) h. The longest and shortest total development time of the mites were obtained as 62.6 ± 1.66 and 14.2 ± 0.20 days at 15 and 32.5 ºC, respectively. As temperature increased from 15 to 32.5 ºC, the life span of the mites decreased from 83.5 ± 2.14 to 24.7 ± 0.39 days, respectively. The highest and lowest total fecundity was observed as 37.3 ± 1.63 and 6.3 ± 1.06 eggs at 17.5 and 15 ºC, respectively. The highest intrinsic rate of increase (r) was obtained as 0.1108 ± 0.005d-1 at 30 ºC. The mean generation time (T) ranged from 78.1 ± 2.8 to 19.1 ± 0.2 days at 15 and 32.5 ºC. Survi-vorship data (lx) of adult females were summarized and compared using the shape and scale parameters of the Weibull frequency distribution model. The lower temperature threshold (t) and thermal constant (k) of the immature stages were estimated using the Ikemoto and Takai linear model to be 8.9 ºC and 361.3 degree days (DD), respectively. The optimum temperatures were calculated by selected nonlinear models including Analytis1/Allahyari, Hilbert and Logan, and Logan-6 models to be 33.10, 33.90 and 32.40 ºC, respectively.

The laelapid mite, Gaeolaelapsaculeifer (G. Canestrini) is widespread in soil habitats and feeds on different small arthropods, fungi and nematodes. The development and fecundity of G. aculeifer feeding on Rhizoglyphus echinopus (Fumouze & Robin) as prey was studied at eight different constant temperatures which include: 16, 17.5, 20, 22.5, 25, 27.5, 30 and 32.5 ºC, with relative humidity of 60 ± 5%, and a 16:8 h (Light: Dark) photoperiod. The results showed that the development time of immature stages were 30.80 ± 0.68, 30.57 ± 0.42 days at 16 °C; 8.66 ± 0.09, 8.20 ± 0.18 days at 30 °C and 9.86 ± 0.19, 9.77 ± 0.22 days at 32.5 °C for females and males, respectively. The pre-oviposition period considerably varied from 7.60 ± 3.02 days at 16 °C to 0.81 ± 0.09 days at 30 °C and then increased to 2.07 ± 0.25 days at 32.5 °C. The oviposition period decreased with increasing temperature from 36.93 ± 2.66 days at 20 °C to 17.67 ± 1.90days at 32.5 °C. The average life span of females was 102.40 ± 8.08 days at 16 °C and 37.21 ± 1.98 days at 32.5 °C. The mean daily oviposition per female increased from 0.49 ± 0.14 at 16 °C to 3.76 ± 0.13 at 30 °C and decreased to 1.88 ± 0.15 at 32.5 °C.

Aegyptobia pirii sp. nov. is described and illustrated based on female specimens collected from Bromus tectorum L. (Poaceae) in Tuyserkan, Hamedan province in Iran. A key to all known Iranian species of the genus is provided.