Journal of Entomological Society of Iran
Year:2015 | Volume:35 | Issue:2|Papers Count:10

Biology and population growth parameters of Jasmine whitefly, Aleuroclava jasmini (Takahashi) were studied on four orange cultivars including Siavaraz, Valensia, Mars and Washangton under laboratory conditions (27±1oC, 60±5% RH and 14: 10 h L: D). The mean immature developmental times of females on Siavaraz, Valensia and Mars were 31.38±0.23, 28.43±0.68 and 29.20±0.67 days, respectively.A. jasmini survived only up to third nymphal instar on Washington cultivar. Immature mortality was 25.77±0.43, 32.00±0.29 and 32.00±0.52% on the above cultivars, respectively. Mean sex ratios (percent of females) were 59.45±0.45, 54.05±0.63 and 51.76±0.44% on above mentioned cultivars, respectively. The mean females longevity was 3.40±0.11, 5.15±0.20 and 4.60±0.22 days, respectively, on cultivars. Mean total fecundity was 25.53±1.45, 40.00±1.62 and 33.66±1.87 eggs on cultivars, respectively. Intrinsic rate of increase (rm) was 0.055±0.001, 0.065±0.003 and 0.060±0.002 number of female/female/ day and Net reproductive rate (R0) was 6.46±0.51, 7.71±0.54 and 11.41±0.60 offspring/individual on the above mentioned cultivars. Finite rate of increase (l) was 1.05±0.001, 1.06±0.003 and 1.07±0.002 per days and Mean generation time (T) was 33.6±0.221, 31.09±0.435 and 31.69±0.639 days on the above mentioned cultivars. Doubling time (DT) was 12.48±0.106, 10.55±0.186 and 9.02±0.183 days on the above mentioned cultivars. Based upon the biological characteristics and life table parameters, Valensia was found to be the most suitable cultivars for development and reproduction of A. jasmini.

The tomato leafminer, Tuta absoluta (Meyrick), is an important pest of potato, Solanum tuberosum L., in the world. In this research, life history parameters of this pest were studied on six potato cultivars including: Impala, Agria, Savalan, Florida, Emeraude and Markies. The development time of larvae on Florida and Impala was significantly longer than of that on Markies and Emeraude. The lowest survival rate from egg to adult was observed on Florida (60.48%). The number of eggs laid per female on Florida was significantly lower than on Agria, Savalan, Markies and Emeraude, but no significant difference was found between Impala and Florida. The lowest intrinsic rate of increase (rm) (0.058 day-1) and the lowest finite rate of increase (l) (1.059 day-1) were recorded on Florida. Moreover, the longest generation time (T) (33.60 days) and the longest doubling time (DT) (11.93 days) was significantly observed on Florida. Therefore, it could be concluded that Florida is the least suitable host to T. absoluta amongst the six tested cultivars of potato. These results could be useful in integrated management programs of T. absoluta in potato fields.

The drought phenomenon in recent years has increased the oat aphid (Sitobion avenae Fab.) population in khuzestan wheat fields. Considering the existence of different natural enemies of this pest in cereal fields, the best control method would be based on selective pesticide application which is less harmful to environment and natural enemies. Thus determination of pest Economic injury level (EIL) became a necessity to prevent immethodical usage of pesticides in wheat vulnerable agroeco system. Hence, an experiment was conducted in complete randomized block design based on split plot with two factors and three replications including growing stages and aphid density in Chamran cultivar in agricultural research station of Ahwaz during 2010 to 2011. Growing stages (Early, middle and late of milky stage) and aphid density (0, 5-10, 11-15, 16-20, 21-25, 26-30 and 31-35 aphid on spike) were considered as mainplot and subplot, respectively. All treatments applied in a net cage. Averages of yield in different aphid density treatments were grouped by Duncan- multiple range test. Regression equations and curves were obtained between aphid density and seed weight in each spike. Grain threshold method was used to EIL measurement. The results showed that EIL was 17, 22, 42 aphids/spike in early, middle and late of milky stage of wheat with no calculating of natural enemies but ET was 12, 17, 31 aphids/spike in the first year and EIL was 9, 18, 49 aphids/spike and ET was 7, 14, 37 aphids/spike in the second year. Also, EIL was 8, 16, 44 aphids/spike and ET was 6, 12, 33 aphids/spike in 2014-2015, respectively.

Leopard moth, Zeuzera pyrina L. (Lep.: Cossidae), is a key pest of walnut in Iran. The efficiency of mating disruption by two commercial products including Isonet® Z and Zeumat Universe® was evaluated in 2011 in East Azerbaijan and Kerman provinces. In each hectar, 300-600 pheromone dispensers for mating disruption were attached to the trees before the emergence of adults. Three pheromone traps were also installed in each plot to evaluate the orientation disruption before the adults' emergence. The pheromone traps did not capture any adult in the plots where mating disruption was performed during the experiment in both provinces while the traps caught the adults in the control plots. This result confirmed the efficiency of the used number of products for orientation disruption of the males. The averages of the number of larval entrances on the branches of plots where mating disruption was conducted by Isonet® Z, Zeumat Universe® and control were respectively 0.18±0.03, 0.13±0.02 and 0.45±0.04 in Kerman province, 0.18±0.03, 0.33±0.04 and 0.63±0.07 in East Azarbaiejan province and 0.18±0.02, 0.2±0.02 and 0.52±0.04 (average±S. E.) for the pooled data of both regions. There was a significant difference among the averages (P<0.01). The results showed the efficiency of mating disruption technique by both products for reducing the damage of the pest even after one year. The number of larval entrances on the branches of the trees in mating disruption plots was 60-70% less than control plots. The results confirmed that the mating disruption with 300 pheromone dispensers of each product is efficient for reducing the damage of the pest in the walnut orchards.

In this study, a total of 98 Iranian and exotic rice genotypes were tested for their resistance to the Striped Stem Borer, Chilo suppressalis, under field conditions in Rice Research Institute of Iran, Mazandaran branch, Amol. The experiment was carried out in a randomized complete blocks design and three replications. At the reproductive stage, five whole plants per plot were randomly selected and cut off at the base, and percent of white head, number of larvae per hill, plant height, stem diameter, and tiller number per hill were measured. The rice genotypes Novator, G2-Gan74, Estrella, Rashtline-1, and IR72860, had the lowest amount of percent of white head, with means of 1.6%, 2.7%, 2.3%, 2.8%, and 3.2%, respectively, and the genotypes IR72-B, Iranian-New-Hybrid, Fars promising line, IR64-MutantW, IR50 had the highest amount of percent of white head with means of 43.5%, 43.4%, 37.6%, 35.8 %, and 34.8%, respectively.Moreover, genotypes Novator, Estrella and G2-Gan74 had the lowest mean larvae per a whole plant (0.1, 0.1 and 0.2, respectively), while genotypes Chinese-Hybrid1, IR72-B, and Binam had the highest mean larvae per a whole plant, with means of 10.3, 9.7, and 8.9, respectively. Rasht-Line-1 had the lowest mean plant height (74.4 cm), Fars promising line had the lowest mean number of tillers per hill (9.13), and Iranian New-Hybrid had the lowest mean stem diameter (4.44 mm). On the other hand, the Tarom-ARG2 genotypes had the highest mean plant height (138.26 cm), Sahel had the highest mean number of tillers per hill (17.6), and Dorfak had the highest mean stem diameter (12.72 mm).There were significant correlations between percent white head and the number of larvae per a whole plant, and between percent white head and number of tillers per hill, but there no significant correlations was found with plant height and stem diameter. The rice genotypes were grouped on Ward’s clustering procedure into two main clusters, totally four subcluster.The rice genotypes such as Novator, Estrella, Rashtline-1 were found to be less sensitive to Chilo suppressalis.Also, in this study, 19 rice genotypes including Novator, Estrella, G2-Gan74, Rashtline-1, Shirodi, Nemat, IR64-Mutant-F3076, MashhadDomsiah/Neda, {(A78.1/LocalAbiji) / (khazar/Tarom)} were recognized as resistant genotypes at field condition. Some of them can be tested in further experiments.

A part of population of the beet moth, Scrobipalpa ocellatella (Boyd) in severe winter condition overwinters as larvae. In order to study overwintering potential of the pest, last instar larvae were collected monthly from September 2011 to March 2012. Seasonal changes in cold hardiness indices such as supercooling point (SCP) and lower lethal temperature of the beet moth were studied. The mean supercooling points of field collected larvae varied from –15.0±0.99 to –17.8±0.92oC. Samples collected in October exhibited about 50% mortality, after 24 h exposure to -12oC. It was gradually decrease until January (no mortality was observed) in January. Lethal temperature for 50% mortality (LT50) decreased from -13.2oC in October to -16.4 ºC in January.Super cooling points of overwintering larvae thorough the winter did not change significantly; while during the gradual decrease in ambient temperature, cold tolerance of S. ocellatella is progressively increased.

Aphis gossypii Glover (Hom.: Aphididae) is one of the most important pests in greenhouse and field. Considering the importance of human health and the environmental protection, reduction in pesticide application has to be considered as an essential issue in the pest control program. In the present study, effects of ethanolic extracts of Rosmarinus officinalis L. and Nerium oleander and an insecticide, imidacloprid were evaluated against Aphis gossypii. Leaf dipping method was used in the laboratory conditions (temperature of 25±1oC, 65±5% relative humidity and 16 h light: 8 h dark).After 72-h, LC50 values of imidacloprid, plant extracts from rosemary and oleander were estimated 0.004, 24.69 and 45.26 mg/ml, respectively. In this study, the effects of sublethal concentration (LC30) of each treatment was evaluated against A. gossypii. Longevity and the number of offspring were estimated per female per day. In this experiment, significant effects were observed on the life table parameters such as survival, intrinsic rate of increase, net reproductive rate, finite rate of population increase and mean generation time, for aphids fed on the leaves treated with ethanolic plant extracts and imidacloprid as compared to the related controls. This information provides further support for plant extracts of R. officinalis and N. oleander having a good potential to control the A. gossypii. However before claiming firm conclusions, trials under glasshouse and field related conditions are needed to verify the applicability of these two plant extracts in control of A. gossypii.

In 2013, during a bioacoustic investigation upon bushcrickets (Orthoptera, Ensifera) in Azarbaijan-e Sharghi, north-west of Iran, some ensiferans were collected in Azarshahr and identified as Polysarcus denticauda (Charpentier, 1825) (Tettigoniidae: Phaneropterinae). This is the first record of the species from Iran. Herewith, several diagnostic morphological and bioacoustic remarks are given.

During faun survey on parasitoids wasps of Coccoidea in Mazandaran province (north of Iran) collected two species of the family Encyrtidae and one species of Aphelinidae family (2010-2013). One species collected from Chionaspis salicis on Salix acmophylla from Amool in April 2012. This parasitoid was later identified as Adelencyrtus brachycaudae Xu& Shi, 1999. The other species was collected from Planococcus citri on Citrus aurantum from Jouybar in April 2013. This parasitoid identified as Clausenia purpurea Ishii, 1933.Theses parasitoid wasps belonging to Encyrtidae. Also Coccophagus yoshidae Nakayama, 1921 collected from Coccus hesperidumon Euonymus fortune from Sari in September 2013. This parasitoid wasp belonging to Aphelinidae.All of these parasitoid wasps identified by Dr. Zhi Hong Xu from China. These parasitoid wasps are new for Iranian fauna.