Iranian Plant Protection Research
Year:2008 | Volume:22 | Issue:2|Papers Count:22

During a survey for detection of PVS in potato fields in Northern Khorasan province, some tubers from the plants which have been already marked and showing mosaic, rugosity, undulation on leaf margins, little leaf and slightly vein deepening, were collected in Bodjunrd region, Also, some tubers from potato fields of Mashhad, Chenaran, Ghoochan, Faruj and Shirvan regions were randomly collected. These tubers maintained in 40C until their dormancy broken, and then grown at greenhouse conditions. On the base of reaction of differential hosts a few plants have been infected with PVS. In host range studies infected sap from one of potato plants, infected Nicotiana debneyi Domin. and Lycopersicon esculentum L.cv. early urbana 111 Systematically, It also developed chlorotic local lesions on Chenopodium amaranticolor Costa & Reyn. And C. quinoa Wild as well, but Datura stramonium L., Phaseolus vulgaris L. var. red kidney. and Capsicum frutescens L. did not show any symptoms in this study. The virus indentifed as PVS on the basis of differential host reactions. The isolate was propagated on N. debneyi and purification was carried out according to Hammond & Lawson procedure (1988) with some modification. The antiserum was provided against partially purified virus. Serological tests including double diffusion in agar and ELISA were performed. Electron microscopy showed intact filamentus particle of virus measuring 629 nm (57000x). To determine infection percent of PVS in Bodjnord region, 200 plants were randomly collected and ELISA tests have been used. The results showed the infection rate of 15.5 percent in Bodjnurd region.

Due to economical importance of stored product pests and resistance to conventional insecticides, it is necessary to use novel and suitable compounds in control programs. Therefore, we evaluated the toxicity of spinosad to three important storage insect, Red flour beetle, Tribolium castaneum (Herbst), Rice weevil, Sitophilus oryzae (L.), Sawtoothed grain beetle Oryzaephilus surinamensis (L.). One-day old adult insects were exposed to different concentrations of spinosad. The exposure times were 1, 10 and 20 d for oral trials. Experiments were performed in complete randomized block design with 4 replications. After treatment the samples were held under constant conditions in laboratory rearing room (27±o2c, 65±5r.h and 14 D: 10 L photoperiod). For T. castaneum the maximum mortality rate was achieved with 95ppm of spinosad after 10 d. Application of 80 ppm spinosad after 10 days caused maximum mortality rate in S. oryzae. The complete control of O. surinamensis was occurred with 150ppm during 20d, the required concentrations for complete cessation of adult emergence were 95, 80 and 150ppm of spinosad for T. castaneum,  S. oryzae and O. surinamensis, respectively.

Beet soilborne virus (BSBV) is a member species of the genus Pomovirus with rigid rod particles and 3 positive single stranded RNAs. The virus is transmitted by Polymyxa betae and restricted to Chenopodiaceae. A survey was conducted in 2005 for identification of BSBV in Northern Khorasan province. Samples showing yellowing, elongated and upright petioles with narrow leaf lamina and hairy roots were collected from fields of Shirvan, Bojnord and Esfarayen. Detection of BSBV was based on TAS-ELISA test. Our survey showed that different fields in Shirvan and Bojnord were infected with BSBV. Also for detection of mixed infection with BNYVV, samples were tested by DAS-ELISA as well. Our investigation showed that some fields in Shirvan and Bojnord had mixed infection with both viruses. This is the first report of infection with BSBV in Shirvan and Bojnord located in Northern Khorasan province.

In a laboratory study the effect of three insecticides (pirimicarb, pymetrozine and spinosad) was evaluated on Aphelinus mali a parasitoid of woolly apple aphid. To investigate the contact effect, adults were caged for 16 hours in petri-dishes containing apple leaves sprayed with each insecticide. To determine the oral toxicity in the same period of time, other petri-dishes containing filter paper soaked in poisoned solution of 10% sugar were used. To determine the repellency effect of the insecticides in question, we used busvine Y shape tube and host choice experiment between treated and untreated leaf disks was carried out. The results revealed that the rate of mortality was 89.43 and 89.01% spinosad in contact and oral testes respectively. In the case of pymetrozine and in similar tests 78.85 and 62.72% mortality was observed. Moreover, spinosad and pirimicarb showed marked repellency effect on the adult stage of A.mali while pymetrozine didn’t show similar effect.

Different responses of silkworm larvae under various rearing climate condition would help to obtain better economic performance of some silkworm verities in specific climate conditions. The effect of 4 rearing climate conditions including 1) standard 2) high temperature and humidity, 3) high temperature and low humidity and 4) temperature fluctuation were investigated on the performances of six different silkworm hybrids including 151x152, 151x110-32, 151x154,103x104, 31x32 and 107x110. All hybrids showed better performances for larval, pupa and total vitality under standard conditions compared with the other rearing environments. There was no significant difference for the good cocoon percentage between the hybrids of 151x152, 151x154 and 107x110 under standard temperature fluctuating and warm/dry climate condition. The hybrid of 151x110-32 at standard condition and the hybrids of 103x104 and 31x32 at standard and warm/dry conditions produced higher values of good cocoons. For all hybrids, the larval mortality increased by growth of temperature and humidity. Meanwhile the pupal mortality rose with increasing of temperature either in dry or humid condition. The highest productivity (weight of total and good cocoon per 10000 larvae) within all treated hybrids obtained under standard and temperature fluctuation of temperature left no adverse effect on single cocoon weight for hybrids of 151x110-32, 31x32 and 107x110, while significantly increased the cocoon weight for hybrid of 103x104. The obtained results provide high temperature and humidity, high temperature and low humidity, and temperature fluctuation decreased production level. Furthermore, 103x104 hybrid is suitable for regions with temperature fluctuation. Also 103x104 and 31x32 hybrids are suitable for regions with high temperature and humidity, and high temperature and low humidity.

To study Virulence and molecular polymorphism variation of Puccinia striiformis Westend. f.sp.tritici Eriks. (Yellow rust disease agent) in Iran, 86 isolates were collected from all around the country. Race determination was carried out according to Johnson et al. (1972) method. In addition, isolates were analyzed by AFLP method by four primer combinations. According to the results of race determination, 35 Physiological races were identified. Race 178E0A- with 7 members was the most frequent followed by Race 64E241A+ with 5 members. Virulence was not detected on the commercial cultivars having Yr1 (Except for 4 Isolates), Yr3, and Yr5 genes. Virulence for Yr2, Yr24, Yr7 and YrA was detected in all around the country. In average for every Primer combination 78 bands were recorded that 30 percent of them were polymorphic. Analysis of data by NTSYS software grouped all isolates in 9 main groups as A, B, C, D, E, F, G, H and I, and 10 single isolates groups in 77% similarity coefficient. There was significant relationship between geographic origins and AFLP fingerprinting groups. However there were not certain relationship between races and these groups.Genetic similarity between most of populations and West/Northwest population (contain Ilam, Hamadan, Kermanshah and Ardebil provinces) was more than 65%. This similarity may be because of Sudanian and mediteranian flows in transferring of spors from Northwest of Iran to North and Southwest of Iran and concluded to a gene flow.

In order to evaluate the effects of rice conventional herbicides on rotational second crops (lettuce, cress, clover, canola and radish), soil microbial biomass and diversity, a field and glasshouse experiments were conducted in Mazandaran province and research glasshouse of Ferdowsi University of Mashhad, respectively. Five experiments were carried out for 5 second crop separately with treatment of different herbicide residue (1-Butachlor 5 l/ha, 2-Thiobencarb 5 l/ha, 3-Oxadirgyl 3l/ha, 4-Sunrice 3 l/ha, 5-setoff 150 g/ha and 6-check without herbicide) by using randomized complete block design. Stem and root length, stem, root and total weight (root + stem) in two harvests (20 and 40 days after planting) were measured and ANOVA was performed. In the first harvest mean comparison showed that canola, lettuce and radish were not affected at 95% confidence level by herbicide residue in any measured variables. Clover stem length and weight were not affected by residue of any herbicides, however clover root length was affected by Butachlor residue and was 28٪ lower than control. Butachlor residues also led to root and total weight reduction in clover. Butaclor residues also affected cress stem and total weight. In the second harvest canola, clover and radish in all variables were not significantly affected by any herbicide residues. Sunrice residues reduced stem length significantly in lettuce. Lettuce stem and root length and cress in stem and total weight were affected by Oxadiargyl residue.

Downy Mildew of cucurbits is one of the most important diseases of cucumber in humid areas and greenhouses. Damage of disease is estimated 50% to 100% in suitable climatic conditions. Therefore, achieving resistant or tolerant genotypes can be designed as the most important and safe method to reduce the damage and increase the benefits of cucumber farming. In order to evaluate the resistance of cucumber germplasms available in Iran, an experiment was conducted using 72 genotypes including 20 native genotypes from Iran National Gene Bank, 49 commercial hybrids from different seed companies, and 3 native population from Tabriz (Basmendj), Babol (Local Babol) and Cossackitan (Local Cossack). The mentioned genotypes were inoculated with 5 ml of 5×103 of sporangium. In field conditions, 21 genotypes, with Local Sari, were studied. It was resulted that Voyaj F1 from Russia and KC361065, KC361105 and TN 94135 from Iran National Gene Bank, and GH5 as a commercial cultivar showed resistance under greenhouse conditions. FDC101 was considered resistant. It was concluded in vitro 4 genotypes and in vivo 8 genotypes found tolerant, whereas, were grouped in susceptible category. In this study, different reactions of fungus isolates were detected in some genotypes. This showed the existence of physiological races for Pseudoperonospora cubensis in Iran.

During growing seasons of years 2006 & 2007, a faunistic survey on Syrphidae family (Diptera) in agroecosystems of Neyshabor region, Khorasan-e-razavi province was carried out. In this study, 3 collection methods: Yellow water trap, Malaise trap and Sweeping net were applied. The results showed a large difference between different collection methods. Specimens of 14 species collected by Malaise trap while Yellow water trap collected 5 species and 8 species exclusively collected by sweeping net. In total, 22 species belonging to 14 genera have been identified. All species are reported from the region for the first time. Among these, E.tricolor & H.trivittatus are new for Khorasan-e Razavi province fauna. Recording the species, E.jacobsonii from Neyshbor, the distribution range of this Syrphid which was restricted to south east Iran is extended. Shannon-Weiner index of biodiversity measured for Malaise trap was higher than that calculated for yellow water trap.

In order to identify the biodiversity of plant parasitic nematodes in vegetable fields of Tabriz, during 2004-2005, 88 soil and a few root samples were collected from rhizosphere of 25 dominantly cultivated vegetable crops. Nematodes were extracted by combined sieving and centrifugal–flotation method and processed to be transferred to glycerin. After preparing microscopic slides, the morphological and morphometrical features of the nematodes were studied using the light microscope equipped with a drawing tube. The morphological features and measerments of the extracted nematodes were compared with those ones given in literature and similarities and differences with original descriptions and closest species were discussed. As a result, 25 species belonging to 16 genera including Amplimerlinius globigerus, Aphelenchus avenae, Aphelenchoides bicaudatus, A. haguei, A. richardsoni, Boleodorus thylactus, Criconema mutabile, Criconemoides informis, C. mongolensis, Ditylenchus medicaginis, Filenchus vulgaris, Geocenamus brevidens, G. rugosus, Helicotylenchus digonicus, H. exallus, H. pseudorobustus, H. vulgaris, Heterodera cruciferae, Mesocriconema antipolitanum, M. curvatum, Paratylenchus mexicanus, Pratylenchus alleni, P. neglectus, Psilenchus hilarulus and Zygotylenchus guevarai were identified. Most of the nematodes are already recoded from Iran and herein, three species namely, Aphelenchoides haguei, Aphelenchoides richardsoni and Pratylenchus alleni and one newly reported species (Helicotylenchus exallus) are described.

A field experiment was conducted at plant pest and disease research Institute in Karaj, Iran in 2005-2006 to determine the effect of low herbicide dose of Clodinafop-propargyl on percentage of wild oat control, yield and economic return of wheat. The experiment included 2 Wheat varieties (Rooshan and Niknejad (less and more competitiveness cultivar, respectively, 4 Wild oat densities (0, 25, 50 and 75 plant m-2) and 4 herbicide doses (0, 25, 50 and 75 (recommended rate) lit ha-1 (100%, 66%, 33% and 0% reduce herbicide dose respectively)) in factorial trial based on randomized block design with 4 replications. The highest wild oat control was obtain in recommended rate and reduce dose to 33 and 66% decreased wild oat control to 0.8 and 38.39% ,respectively. Yields generally increased as rates increased recommended dose. There is no different between 33% reduce on the recommended dose and recommended dose, but 66% reduce on recommended dose couldn’t produce pleasure yield. In two cultivars economic returns increased exponentially as rates increased recommended dose, the maximum economic return was observed at the recommended herbicide dose but hadn’t different with 33% decrease in dose of herbicide. Results of this study indicate reduction to 33% from the full recommended dosage is possible when wheat was grown in optimal density in weedy condition.

Recently weed scientist are more interested in weed management by allelopathy. The main objective of the study was to evaluate allelopathic potential of sunflower on redroot pigweed and common lambsquarter. This study was conducted in two series of laboratory and greenhouse experiments. Under laboratory conditions, leaf, stem and root aqueous extracts of sunflower at 0%, 2.5%, 5%, 7.5 % and 10% (m/v) concentrations were applied to determine their effect on redroot pigweed and common lambsquarter seed germination and initial growth under laboratory conditions. The results indicated that germination and mean daily germination was reduced by this extracts by 43% and 50% respectly. The effects of leaf and stem extracts on germination were more than root extracts of sunflower. The percentage and quality of germination was decreased by increasing the concentration of extracts. The root length and shoot length were reduced by 80% following application of sunflower extracts. In greenhouse experiments, to study the role of decomposition plant debris on release of allelochemicals, stem, root and leaf residues of sunflower were incorporated with pot soil by 5% (w/w) and weed seeds were sown and samples were taken in five stages of growth(2, 4, 6, 8 leaf and mature plant). Dry weight, leaf area and height of weeds were determined. The results of greenhouse experiments indicated that incorporation of sunflower residues in the soil (fresh or decomposed residues) reduced growth of redroot pigweed and common lambsquarter. The difference between fresh and decomposed residues was not significant. This study indicated that, fresh stem residues of sunflower are able to apply, its harmful effects on dry weight, leaf area and height of both weeds species.

In order to determine efficacy of some registered graminicides in control of resistant and susceptible ryegrass biotypes, two greenhouse trials were conducted at weed research department of Iranian plant protection research institute during 2007. Experimental design was completely randomized design with eight replications. The susceptible and resistant biotypes were treated by 19 herbicides included 10 acetyl-CoA carboxylase inhibiting herbicides, 6 acetolactate synthase inhibiting herbicides and 3 herbicides with different mode of action. Ryegrass biotypes were treated in 4 leaves stage by recommended dose of herbicide. Number of survived plant per pot, fresh and dry weight (30 days after herbicide application) and EWRC visual rating (15 and 30 days after herbicide application) was measured.  Results showed that clodinofop-propargil cycloxidim, pinoxadon (at 450 and 600 ml.ha-1), iodosolforon + mesosolforon (chovalieh), iodosolforon + mesosolforon (Atlantis) and isoprotron + diflofnikan had very good to optimum control of susceptible biotype. Results also indicated that cytoxidim, iodosolforon + mesosolforon (Atlantis), pinoxadon at 600 ml.ha-1 and isoprotron + diflofnikan had very good to optimum control of resistant biotype. Diclofopmethyl, cytoxidim and clorosolforon had less optimum control of susceptible biotype. Finally, iodosolforon + mesosolforon (Atlantis), isoprotron + diflofnikan and pinoxadon at 600 ml/ha were advised to control resistant biotype to acetyl-CoA carboxylase inhibiting herbicides in wheat fields. It is also recommended to consider crop rotation as well as herbicide rotation to use these herbicides continuously.

Sclerotinia sclerotiorum is the causal necrotroph pathogen with wide host range and showed various phenotipic intraspecies variability. Considering to difficult identification of intraspecies heterogeneity on the basis of phenotypic factors, compatible mycelium groups introduced as an appropriate tool for classification and intraspecies heterogeneity distinction. In this research, 19 fungal isolates purified from canola and paired on modified Patterson’s medium (MPM) with red food colour. Pairings were scored as compatible when isolates merged to form one colony but mycelia incompatibility pairings resulted in an interaction zone in which a distinct reaction line and abundant aerial mycelia or thin mycelial were observed. But, incompatible mycelial with occurrence of interaction zone by red food colour in reaction zone on medium showed there is no potential of heterokaryon to be stable when two isolates were paired. All pairings of self isolates were compatible and five mycelial incompatible groups in isolates observed. Microscopically, mycelial interactions in pairings of isolates were complex. Anastomosis between paired isolates was not always observed. Incompatible pairings were followed by hyphal deterioration that was not observed in compatible interaction. The result showed that a high level of mycelial incompatibility exists among isolates of S. sclerotiorum, comparable to level of vegetative incompatibility reported in other ascomycetes. The extent of mycelial incompatibility indicates that the genetic heterogeneity exists within the species and the mycelial compatibility- incompatibility reactions may be an effective way of categorizing intraspecific heterogeneity. 

This study was mainly conducted due to importance of plant manna and their production process regarding pharmaceutical use. Therefore, the behaviourial characteristics of Spittlebug Poophilus nebulosus Leth on Alhagi persarum Boiss & Buhse Camel thron plant in Torbate Jam region, Khorasan Razavi state were assessed during 2006 and 2007. The bug’s discharge after feeding on the camel thorn plant is hedysarum which is a sweet liquid with pharmaceutical effects. In European references, this manna is referred to as the Persian manna’. In this study we found out that the bug has 5 instars and 3 generations per year. The first generation activity starts from the (late April) and the instars make a great amount of foam at the bottom section of the plant while they live inside the foam. The adult bug appears in late April and moves out of the foam, creates a non-sweet and non-crystallized discharge which dries out as a white powder on the plant. The second generation which appears in mid June is different from the first generation regarding the behaviourial issue as they have an independent life, are resilient and enormously active, stay at the browse of the plant and do not create any foam. The first hedysarum manna crystals are produced by this generation in late June. The activity of the third generation is similar to the second. Hedysarum manna production continues as mentioned until the end of autumn. By the end of autumn the female bug lays the eggs underneath the skin of the stem. The spittlebugs in Torbate-Jam region prefer the plants which are less damaged according to exploitation of hedysarum. There is evidence that the bug was not capable of foam production on the browse of the camel thorn plants and the process was ceased after a short period of time. We also found out about the rapid reproduction of foam by the instars after long-term spring rain and foam clean up from the plant.

Currently in IRAN, some manual methods are used for measuring spray droplet size which is very laborious and time consuming. In this paper, a software is presented based on image processing techniques, which is suitable for small object detection purpose that can be used in blob analysis of sprayer calibration and other similar applications. The algorithms have been implemented and adapted in a program called Scientific Image Blob Analysis (SIBA). The program can read the scanned image of water sensitive cards, obtained from nozzle's spray. Some threshold techniques are also used for noise removal and converting the original image to a binary one (e.g. red for blob and white for background). The blob features calculated in the program are area, actual diameter, Number Median Diameter (NMD), Volume Median Diameter (VMD), blob density (blob/unit area), and percentage of blob's area coverage, blob count and finally the uniformity of spray. The algorithms were evaluated analytically and experimentally, comparing with the results of a leaf area meter and a planimeter. Although the results showed more accurate and faster performance for this software, a direct correlation was also found between their accuracy and the image's resolution. In other words, the higher the resolution of the image, the more accurate of the results particularly for the smaller blobs. This was mainly due to the stepwise inherent of the pixels showing a blob's boundary. However, by choosing an appropriate resolution the error of measurement may reduce to %1. The program can also easily be used for any area detection and calculation of the images such as leaf, fruits etc. It is a good package especially for the researchers in the developing countries with a limit access to similar resources. Moreover there might be some uncertainty about the accuracy of such commercial products.

Fluorescens pseudomonads can suppress soil-borne plant pathogens by employing several mechanisms such as competition for iron by means of siderophores. Three indigenous strains Pseudomonas fluorescens (UTPF5, UTPF61 and UTPF76), Pseudomonas aeruginosa 7NSK2 and its pyoverdin mutant, MPFM1, were used for investigation the effect of iron competition on bean damping-off suppression. The rates of siderophore produced by strains were determined quantitatively. Results demonstrated that 7NSK2 with 625.29 µM had the most ability of pyoverdine production. Study of the role of different iron and zinc concentration on siderophore and HCN production exhibited that iron increased HCN and decreased siderophore production significantly. Appling of iron chelates and purified pyoverdine indicated that susceptibility to iron competition is correlated to type of chelates and fungi species. Pythium aphanidermatum and R. solani exhibited the most and the lowest susceptibility, respectively. Effects of iron chelates and zinc sulphate on biocontrol activity of strains were assessed in greenhouse condition. By providing of iron and subsequently decrease of iron competition, chelates reduced biocontrol activity especially in the case of UTPF5. This strain suppressed disease and increased plant growth in absence of iron chelates. Pyoverdine mutant, MPFM1, showed moderate biocontrol activity in compartion with wild type. 

In order to evaluate chemical control of bermudagrass (Cynodon dactylon (L.) Pers.) on mixture turf: (Lolium perenne 20%,Poa pratensis.20%,Festuca arundinacea 20% and Festuca rubra commutata 40%), an experiment was conducted during 2006 in Tehran, using randomized complete block design with 4 replications and 11 treatments. Treatments were Diclpfop methyl at 900 and 1080 g a.i. ha-1, Fenoxaprop-p-ethyl at 60 and 75 g a.i. ha-1, Clodinafop propargyl at 48 and 64 g a.i. ha-1, Tralkoxydim at 250 and 300 g a.i. ha-1, Sulfusulfuron at 18.9 and 24.5 g a.i. ha-1 and untreated control. All treatments were repeated 4 times during the growth period of bermudagrass. The results showed that bermudagrass's biomass decreased by Fenoxaprop-p-ethyl, Clodinafop propargyl and Tralkoxydim, 20-30, 40-50 and 45-55 percent, respectively. Bermudagrass's density decreased by mentioned treatments, 20-25, 35-40, 5-10 percent, respectively. Bemudagrass's biomass decreased by Diclofop methyl treratments, 15-25 percent, respectively, but Bermudagrass's density did not decrease with mentioned treatments. Bermudagrass's biomass and density did not decrese by Sulfosulfuron treatments. Turgrass damaged by Diclofop methyl and Clodinafop methyl treatments more than 20 percent (biomass and visual rating). The other treatments did not damage turfgrass and did not decrease turfgrass biomass. At the end, despite of having low efficacy, Fenoxaprop-p-ethyl at 60 g a.i. ha-1 (without significant differences between both doses) is recommended for Bermudagrass’s control in mixture turf with mentioned mixtures, because of no damaging turf. 

Common root rot induced by Bipolaris sorokiniana, is one of the most important diseases of wheat. Chemical control of this disease is difficult because of it is a soil-born pathogen, So that, application of other methods is useful to reduce disease level especially resistance cultivars. In this research, were examined reaction of some wheat cultivars and lines against common root rot in greenhouse condition, at summer of 1384. Nine isolates of the fungus were isolated from infected wheat fields in Markazi province and their pathogenicity was examined on wheat. The Pathogenicity of two isolates (Kh and Sh) were more than others, so they were selected and used to compare reaction of fifteen wheat cultivars and lines. The plants were harvested at two times of 4 & 7 weeks after planting. The study was planned in a factorial arrangement in the basis of completely randomized design with 4 replications per treatment. The parameters of patterns were measured were including: 1) dry weight of aerial part and root, 2) percentage of infection at subcrown internodes. The results were analyzed whit SAS & MSTATC. The results showed: that Sh isolate had more pathogenicity rather than Kh isolate and there is significant difference between disease reactions among cultivars. The cultivars Sabalan, Zarrin and Niknejad were most resistance in comparison to other cultivars to common root rot. The Maroon, Bakkras-roshan and Kavir were more susceptible cultivars. The Pishtaz, Alvand, Gaspard, alamoot, Darab2, Marvdasht cultivars, C-78-14 and M-79-6 lines were graded between these two groups.