نشریه تحقیقات نوین در گیاه پزشکی
پیاپی 3 (پاییز 1388)

Abundance of Thrips tabaci Lind., an important pest of vegetables, was investigated on upper and lower leaves of different genotypes of eggplant, including Siah-Mashhad, Borazjan, Black beauty, Siah-Neyshabour, Zabul indigenous, Imami-905, Juybar-Mazandaran, Sarkhoun-Hormozgan and Galami-Varamin, during 2000-2001 in Varamin region. Eggplant seedlings were cultivated in May in a randomized complete block design with three replications. Each replication consisted of four rows of 10 plants. Five leaves were randomly sampled at weekly intervals until October to estimate the incidence and population fluctuation of T. tabaci. The number of thrips was counted on the surface of four square centimeters of leaves using a binocular microscope. All analyses and comparisons were carried out using statistical package SAS. The results showed that there was a significant difference between the number of thrips on upper and lower leaves, so that the number of thrips on lower leaves were several times higher than that of on upper leaves. Borazjan and Juybar-Mazandaran with the mean number of 1.55 and 0.86 had the highest population in 2000 and 2001, respectively. In complex analysis, there was no significant difference between the thrips abundance on lower and upper leaves. Incidence of thrips faced with increase from June, and the maximum number was recorded in early until late July in both years. The results indicated that, a trend of increase initiated from late June in Varamin. Borazjan had more thrips than other genotypes and the thrips abundance in the first year was two times of the second year.

The vine mealybug, Planococcus ficus (Signoret) has been found in most grape-production areas throughout the world. The damage of the pest has increased on grape in some parts of Fars province-Iran during recent years. Some ecological aspects of vine mealybug were studied in vineyards in Jahrom during 2008-2009. Seasonal abundance of vine mealybugwas monitored by time-consuming examination technique. In geographical condition of Jahrom vineyards P. ficus has 5 generations of seasonal abundance from April to November. After fifth generation all stages of P. ficus (female adult, nymphal instars and egg) overwintered on root from late November to next March. Population density of female adult and nymphal instars increased rapidly in May and has a great decline after harvest in August. Vine mealybugs were found in trunk in spring, leaves, buds and fruit in summer, however, the mealybugs always were found in protected locations (under the bark of the trunk).

Palatoria blanchardi Targ. is an important of date palm in Iran. The population was monitored monthly by leaf sampling during 4 years (2000-2004). Sample unit was 3 leaves that taken from 3 strata of the palm canopy of ten trees. Weather data (temperature and relative humidity) were obtained from Abadan meteorology station. Correlation analysis and sigmoid models including Monomolecular, Logistic, Gompertz, Weibull and Richard models were used to study the relationship between population density and weather parameters. Pest activities started in March and population increased by increasing of temperature and humidity. Result showed that there were three overlapping periods of activities in field. The first, second and third periods of activities started in April, September and December respectively. The first period was longest and the third period was shortest. There was significant correlation between population abundance and weather condition including temperature and relative humidity. The order of relative influences of climatic factors on seasonal population fluctuation showed that the effect of temperature was greater than the effect of relative humidity. The highest population occurred when temperature was between 16 º C and 24 º C and relative humidity was between 42 and 63 percent.

The citrus nematode, Tylenchulus semipenetrans, is widely distributed in the citrus orchards of Fars province, Iran. The nematode causes slow decline and serious crop losses. Host resistance is the most effective method for controlling the disease. Seedlings of some rootstocks including Minneola (C. paradise × C. reticulata), Citrus ourantium, C. lmettioides, C. aurantifolia var. Ahvazi (a natural hybrid), C. maxima, Fortunella margarita, C. medica, C. medica var. Otroj, C. lemonia var. Lisbon, C. taivanica, C. volkameriana, C. lemonia var. Eureka, C. aurantifolia, C. grandis, C. lemonia var. Rough Lemon, C. macrophylla (Alemow), Poncirus trifoliata, Swingle Citromelo(C. paradise × P. trifoliata) were evaluated for their resistance to the citrus nematode. The seedlings were planted in the pots and citrus orchard. In case of pot experiments, the three months old rootstock seedlings were transplanted to the pots with 40 J2/g of soil. The roots of seedlings were scored for nematode infestation after six months. For orchard experiments, the five months old rootstock seedlings were transplanted to naturally infested soil in a citrus orchard with 25 J2/g of soil. The roots of these seedlings were evaluated for nematode infestation 4.5 and 15 months after transplanting. The susceptibility of rootstocks to citrus nematode was evaluated on the base of the number of penetrated females per gram of feeder roots. In both experiments P. trifoliata, Swingle citromelo and Citrus ourantium were resistant to citrus nematode, whereas the other rootstocks supported a high population of the nematode.

Barley (Hordeum vulgar) is one of the most important strategical world's agricultural products which stand in the 4th position after wheat, soya and corn, Barley, also attact with several diseases out of which, true loose smut is one of the most important one, which causing qualitative and quantitative losses. Various management strategies are taken into considerations to control the disease. One of the economical methods to manage the diseases is the application of general systemic fungicides. In this study, we evaluated some systemic fungicides including carboxin thiram (Dividend star ®, %75 wp), triadimenol (Baytan®, %7.5 wp), diniconazol (Somi8®, wp), triniconazol (Real®, FS), repectively in various dosage levels of 2, 2, 1/5 and. /2, in comparison with a newer fungicid Dividend star® 036 (FS) also, in various dosage levels, which was taken into studies on a Barley cultivar "Karun dar Kavir" (Nosrat).The experiment was carried out in a Rendomized Block Design (RBD) with the above fungicides in various dosage in 10 treatments in the field conditions at the years of 2006 -2007. The results showed that, the fungicides Dividend® (2ml/lit), Somi8® (2gr/lit), Real® (0.02ml/lit) and Baytan® (1.5 gr/lit) were the most efficient fungicides in the disease control repectively. Carboxy thiram (2gr/lit) and Dividend® (1ml/lit) were the least concerned on the disease control in comparison to other fungicides, including the control.

Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli (Xap), is one of the major diseseas in bean fields leading to significant losses in yield and seed quality. Chemical control is ineffective, therefore, the use of resistant varieties becomes an interesting alternative. The object of this experiment was to screen resistant bean genotypes to CBB. The experiment was conducted at Arak Station of Agricultural and Natural Resources Center of Markazi Province. Bean genotypes were planted in the field at 2 locations. In one locations Xap suspension with 107 cfu/ml was sprayed onto plants befor flowerhng stage. Disease scale was rated from 1 (Immune) to 5(susceptible). The experiment was carried out in agment design in 12 blocks with 234 bean genotypes with 3 checks including Khomein Local Chitti bean, Daneshkadeh white bean and Goli red bean. Evaluated traits in 3 bean checks had no significant difference that meaned the experiment accuracy was high. Fourty one bean genotypes with disease scale ≥ 3 was selected as resistant and semi resistant to CBB.

Samples of the tortoise beetles genus Cassida were collected on Centaurea behen L. across Gachsaran district during a 2-year period between 2008 and 2009. The beetle was identified as Cassida palaestina Reiche. This species is recorded for the first time from Iran and considered an important natural control agent feeding on weedy herbs such as Centaurea behen L.

Through inspections in vegetables and ornamentals greenhouses in Esfahan province, during 2005-2006, some specimens of Collembola were found feeding on the root and crown of wilting or dying seedlings. Identified species and their hosts were as follow: Sinella tenebricosa (Entomobryidae) and Proisotoma minuta (Isotomidae) from African violet, and Ceratophysella sp. (Hypogastruridae) from greenhouse cucumber and parsley. Studies indicated that these collembolans reach to high density, with more damage on plants, in greenhouses and pots with higher humidity and shorter irrigation periods. In the infested plants, secondary roots were devoured completely and the plants could be easily infected by pathogens, due to collembolan damages to plant crown. Among the indicated species, only P. minuta was recorded from Iran, and Ceratophysella sp. might be a new species to the world.

During the investigation of edaphic mite fauna of walnut trees in Estahban (Fars province longitude 29˚ 06 N, latitude 54˚ 01 ́E altitude 1860 m above sea level May-June 2009) and Namak-abrood (Mazandaran province longitude 36˚ 40 ́N, latitude 51˚ 18 ́E altitude 44 m above sea level August-September 2009), some specimens belonging to the family of Alycidae were collected from soil, cleared in lactophenol, mounted in Hoyer’s medium and finally identified as Alycus denasutus (Grandjean, 1937). This is the first report of the genus, and species from Iran. This species belongs to the family Alycidae, superfamily Alycoidea, cohort Alycina and suborder Endeostigmata (Walter, 2009). Length of idiosoma 450.8 µm and its maximum width 264.6 µm; body colour white; prodorsum with 2 pairs of filiform trichobothria; cheliceral shafts abruptly tapering, all tarsi with paired claws and rayed empodium. One solenidion on tibia 1(length 10.5 µm); winding ridgs are long and parallel on dorsum (Uustitalo, 2010). naso redused; median eye absent; chelicerae each with 2 seatae (Moraza, 2008). The species has been found in coniferous and deciduous forests, and is possibly Holarctic. It has been reported from Italy (in moss of pine forest, litters, in Fagus valley, and under Robinia and Avena), USA (in litter dunes) and France (Uusitalo, 2010).

During the investigation of edafic mites fauna of walnut fields in Estahban (Fars province, longitude 29˚ 06 ́N, latitude 54˚ 01 ́E and altitude 1860 m above sea level in spring 2009, a few speciments belonging to the family of Stigmochelylidae were collected from walnut soil, placed in lactophenol, mounted in Hoyer’s medium and finally identified as Stigmocheylus sp. Length of idiosoma and its maximum width were 274.4 µm and 127.4 µm respectively. This is the first record of the family and genus from Iran. This family, which belongs to the order Trombidiformes, suborder Prostigmata and subfamily Paratydeoidea, contains small and, soft-bodied elongate and free living or parasitic mites (Krantz & Walter, 2009). Some morphological characteristics of this family are as follows: Prodorsum with 2 pairs of trichobthria; palps with well-developed thumb-claw process, palptibia usually with at least one claw-like seta distally, palptarsus usually well developed; first and second legs widely separated from legs 3 and 4. stigmocheylid mites are known from Australia, Europe, North America and North Africa. (Krantz & Walter, 2009). Peritremes not segmented; setae c3 absent; setae sci longer than other species (Bochkov, 2008). This species is the first record in the world regarding to this characters.