Applied Entomology and Phytopathology
Year:2007 | Volume:74 | Issue:2 (82)|Papers Count:11

While conducting a research project "Biosystematic study of species of Spermophilus fulvus in Zanjan province” the morphological and biological characteristics of this species were also studied. Thus 72 living samples (45♀ male and 27♂female) were trapped in 4 research sites in various areas in Zanjan province (Zanjan, Sultaniyeh, Abhar and kidar). Morphological characteristics used in this study included: Total length, body and head length, tail length, hind foot length, ear length (mm) and total weight (gr).The morphometric results obtained by studying these characteristics indicated that, the male samples except for their tail length were larger than females. When sexually matured, male animals tend to have a darker color than female ones. In the biological studies, the developmental growth of the animals from birth to maturity was studied, also increase in daily food intake until the beginning of hibernation (AUG 44gr) as well as decrease in food intake during hibernation (OCT-26gr, NOV-4.5gr and DEC-0.gr) was investigated. The longest and shortest hibernation bouts of ground squirrels were found to be 150 and 107 days respectively. In this period, the longest uninterrupted hibernation was 13 days. These samples reproduced twice a year (MAR. and JUN.) and also giving birth to 5-7 babies each time.

Yellow broad mite Polyphagotarsonemus latus is a serious pest in tropical area and glasshouses. In Iran this mite is recorded for the first time on potato plants in 2001 from Jiroft. Biology and population fluctuation of this mite have studied under controlled conditions (25±1°c, 70±10%Rh and LD 14:10), on excised leaf. Duration of developmental stages including egg hatching, nymphal, quiescent and preoviposition periods were recorded as 1.32, 1.1, 1.12 and 1.3 days respectively. The longevity of male and female observed 7.9 and 9.76 days with mean fecundity of 30.53 eggs.Population fluctuations of P. latus studied on six dominant cultivated potato varieties (Arinda, Diamond, Maradona, Primor, Agria and Concord (Ramos and Sante in 2nd year) through weekly sampling from September to February, along with intensity symptoms of injuries and rate of damages. Analysis of variances of collected data showed that, Arinda, Diamond and Primor in first year and Arinda, Maradona and Ramos in second year possessing higher mean density of mites on potato leaves while Agria and Concord in first year and Sante and Concord in the second year had the lowest mite populations. Maximum damages recorded for Arinda followed by Maradona, Diamond and lowest damages observed for Sante varieties According to DMRT method.

Because of their extensive underground structures, control of perennial weeds is very difficult. In this study, factors that influence the germination and control of licorice (Glycyrrhiza glabra L.) rhizomes were studied under laboratory and nursery conditions from 2002 to 2004. Results indicated that Glycyrrhiza glabra L. rhizomes buds did not germinated below 6°c. They need at least 154 degree days before they could germinate. Rhizomes were also exposed to low temperatures (5, 0, -3, -5 and -10oc) under submerged, field capacity and dry soil in a factorial design. Results showed that rhizome buds germination decreased under submerged soil at 5oc. Under all soil moisture regimes no rhizome could survive freezing temperature of -3oc and below. In dessication experiments, no buds survived 10 days of desiccation at 25oc and higher. Totally the results of the experiments showed that the control of licorice (Glycyrrhiza glabra L.) rhizomes with physical methods is possible in laboratory conditions.

Increasing the resource use efficiency in crop will be decreased weed competition. In this study the effects of corn plant density and planting pattern on radiation use efficiency of corn and common lambsquarters studied in a randomized complete block design with three replications and factorial treatment arrangement at Aborayhan Pardis in 2003. Plant density treatment was at two levels: recommended (70.000 plant ha-1) and 1.5 times recommended plant density (105.0000 plant ha-1). Planting pattern treatment was at two levels: one and two rows planting (planting on both of ridge sides) and four common lambesquarters density levels: 0, 5, 10 and 15 plant m-1. The results showed that corn radiation use efficiency decreased in presence of common lambesquarters in different corn plant densities and planting patterns. Higher corn density increased corn and common lambesquarters radiation use efficiencies compared to less corn density. Corn two rows planting pattern compared to one row planting pattern, increased corn radiation use efficiency and decreased common lambesquarters radiation use efficiency.

Six strains of Bacillus which were isolated from wheat field of Markazi, Golestan and Mazandaran provinces and also 11 strains of Pseudomonas fluorescens isolated from wheat fields of Karaj and Markazi province were evaluated as potential biological agents for control of barley covered smut caused by Ustilago hordei in field. The randomized complete design with three replications was used for experiments. Results indicated that Bacillus lichniformis (B1) and B. cereus (B2) completely controlled barley covered smut. The percentage of infection in treatments with Bacillus sp (B2), B. cereus (B4), B. subtilis (53) and B. subtilis (71) ranged from 0.119 to 0.617 and were significantly less than infected control (p < 0.01).The best results were achived with Pseudomonas fluorescens bioV (C15), P. fluorescens bioV (E2), P. fluoresecns (D11) and P. fluoresecns bioI (32). The percentages of infection in these treatments were 0.207, 0.177, 0.133 and 0.18 respectively. Other strains of Pseudomonas were capable of reducing the incidence of covered smut and the percentage of infection significantly less than infected control.

Swallow-wort, is a perennial invasive twining of Milkweed family that has become problematic in many parts of Iran, especially in orchards. Present study was conducted in order to study the effect of temperature on asexual reproduction ability of this weed. The following experiments were conducted in Iranain Research Institute of Plant Protection during 2003-2004: 1- Effect of temperature on root asexual proliferation with 3 factors and 4 replications that the first factor (A) was duration (0 (control), 24, 48, 96 and 192 hrs) of root keeping in oven; the second factor (B) was root length (3, 6, 9 and 12 cm), and the third factor (C) was oven temperature (10, 20 and 30oC). 2- Effect of freezing on root asexual proliferation with 3 factors and 4 replications that the first factor (A) was duration (0(control), 24, 48, 96 and 192 hrs) of root keeping in freezing, the second factor (B) was root length (3, 6, 9 and 12 cm) and the third factor (C) was freezing temperature (-1, -3 and -50C). Under 20 and 30.C temperatures, the roots were completely destroyed, but 10oC for 24, 48 and 96 hours could not kill all the roots. Freezing temperatures of -50C or -3oC for 96 hours killed all the roots. Freezing temperatures of -3oC for up to 48 hours, or -1oC, could not completely kill the roots. Therefore, it seems that desiccation and freezing of roots are suitable approaches for management of swallow-wort.

Three goals were intended to be realized:1- Number of generations of codling moth on apple and walnut trees.2- Comparative study of the dates of initiation and termination of various generations of codling moth on apple and walnut trees.3- Population density of codling moth in walnut and apple orchards.To achieve these goals, various walnut growing regions, including Tooyserkaan, Shahmirzaad (Semnan), Karaj and central Elburz were selected. Research methods were mainly based on pheromone traps and corrugated paper bands. Results are as follow:1- Number of generations of codling moth is exactly the same on walnut and apple trees.2- Generations are accomplished 7-10 days sooner on apple trees than on walnut trees.This point is highly important in achieving effectively the chemical control measures against codling moth in walnut orchards.3- Population density of codling moth is higher in apple orchards than that in walnut orchards (the figures in Farsi text to be consulted).

In order to evaluate the resistance of wild oat (Avena ludoviciana Durieu.) to clodinafop-propargil of aryloxyphenoxypropionate herbicides, green house studies and seed bioassay experiments were conducted in 2002-2004. Greenhouse experiments included screening tests and dose response experiments whereas, seed bioassay experiment included ID50 determination and dose response experiments. The experiments were conducted on the wild oat biotypes collected from Fars, Markazi and Khuzestan provinces, using clodinafoppropargyl herbicide. Greenhouse experiments were conducted as a randomized complete block design with four replications. In green house screening experiments; biotypes of wild oat treated during 2-4 leaves stage using the recommended dose of herbicide. Shoot biomass, survived plant and EWRC visual rating, were performed four weeks after herbicides application. Furthermore, response of all biotypes to 0.1-16 times of recommended dose was measured and their R/S ratio calculated. Seed bioassay experiments were conducted using a completely randomized design with four replications. In these experiments the percentage of coleoptiles length versus control were measured 7 days after herbicide application. In order to determine the ID50 values, a herbicide dose range was applied to susceptible biotype (MS). Furthermore, the response of all biotypes to ID50 of susceptible biotypes was measured. R/S ratios of biotypes were also calculated. The results of both experiments showed that KR1, KR2, KR3 were resistant to clodinafop-propargyl.

During 2006, a survey was conducted on the Miridae fauna of Uromia region and environs and a large number of specimens were collected. Morphological and male genitalia characteristics were used to identify the specimens. According to available literature (Kerzhner Josifov, 1999; Schuh, 2006), Pilophorus perplexus (Douglas & Scott, 1875) is reported for the first time from Iran. The different species of Pilophorus Hahn, 1826 feed on aphids and other small insects on families Rosaceae, Salicaceae, Fagaceae and Tiliaceae. 4 males and 11 females of this bug were collected on Prunus sp. in June, 24. The genus Pilophorus belongs to subfamily Phylinae and tribe Pilophorini. This species has been reported from USA, France, Germany, Italy, England, Spain and Sweden. The specimens are deposited in the insect collection of Plant Protection Department, College of Agriculture, Uromia University. The specimens were identified and confirmed by Dr. R. Linnavuori from Finland.