Agent Of Rust Research Articles

Tranzschelia discolor as the Causal Agent of Rust on Nectarine, Peach, and Japanese Plum in Highland Areas of Northern Thailand.

A severe outbreak of rust disease was observed on Prunus species, P. persica (peach), P. persica var. nectarina (nectarine), and P. salicina (Japanese plum) cultivated in northern Thailand in the rainy season. Previous reports have identified the causal agents as Tranzschelia discolor and T. pruni-spinosae based on only morphological characteristics. Thus, the aim of this study was to identify rust fungi of Prunus spp. based on morphology and molecular analyses. Between May and July in 2020 and 2022, 18 isolates were collected from five areas in Chiang Mai and Chiang Rai provinces. Symptoms of rust consisted of cinnamon brown pustules of uredinia that were hypophyllous and visible as pale greenish to chlorotic yellowish angular spots on the upper leaf surfaces. Urediniospore shape, size, and color were similar to T. discolor. Molecular analysis of internal transcribed spacer (ITS) and partial 28S large subunit (LSU) region rRNA genes confirmed the isolates to be T. discolor. This is the first report of P. salicina as a host of T. discolor in Thailand.

Metabolome profile variations in common bean (Phaseolus vulgaris L.) resistant and susceptible genotypes incited by rust (Uromyces appendiculatus).

The causal agent of rust, Uromyces appendiculatus is a major constraint for common bean (Phaseolus vulgaris) production. This pathogen causes substantial yield losses in many common bean production areas worldwide. U. appendiculatus is widely distributed and although there have been numerous breakthroughs in breeding for resistance, its ability to mutate and evolve still poses a major threat to common bean production. An understanding of plant phytochemical properties can aid in accelerating breeding for rust resistance. In this study, metabolome profiles of two common bean genotypes Teebus-RR-1 (resistant) and Golden Gate Wax (susceptible) were investigated for their response to U. appendiculatus races (1 and 3) at 14- and 21-days post-infection (dpi) using liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (LC-qTOF-MS). Non-targeted data analysis revealed 71 known metabolites that were putatively annotated, and a total of 33 were statistically significant. Key metabolites including flavonoids, terpenoids, alkaloids and lipids were found to be incited by rust infections in both genotypes. Resistant genotype as compared to the susceptible genotype differentially enriched metabolites including aconifine, D-sucrose, galangin, rutarin and others as a defence mechanism against the rust pathogen. The results suggest that timely response to pathogen attack by signalling the production of specific metabolites can be used as a strategy to understand plant defence. This is the first study to illustrate the utilization of metabolomics to understand the interaction of common bean with rust.

An NBS-LRR protein in the Rpp1 locus negates the dominance of Rpp1-mediated resistance against Phakopsora pachyrhizi in soybean.

The soybean Rpp1 locus confers resistance to Phakopsora pachyrhizi, causal agent of rust, and resistance is usually dominant over susceptibility. However, dominance of Rpp1-mediated resistance is lost when a resistant genotype (Rpp1 or Rpp1b) is crossed with susceptible line TMG06_0011, and the mechanism of this dominant susceptibility (DS) is unknown. Sequencing the Rpp1 region reveals that the TMG06_0011 Rpp1 locus has a single nucleotide-binding site leucine-rich repeat (NBS-LRR) gene (DS-R), whereas resistant PI 594760B (Rpp1b) is similar to PI 200492 (Rpp1) and has three NBS-LRR resistance gene candidates. Evidence that DS-R is the cause of DS was reflected in virus-induced gene silencing of DS-R in Rpp1b/DS-R or Rpp1/DS-R heterozygous plants with resistance partially restored. In heterozygous Rpp1b/DS-R plants, expression of Rpp1b candidate genes was not significantly altered, indicating no effect of DS-R on transcription. Physical interaction of the DS-R protein with candidate Rpp1b resistance proteins was supported by yeast two-hybrid studies and in silico modeling. Thus, we conclude that suppression of resistance most likely does not occur at the transcript level, but instead probably at the protein level, possibly with Rpp1 function inhibited by binding to the DS-R protein. The DS-R gene was found in other soybean lines, with an estimated allele frequency of 6% in a diverse population, and also found in wild soybean (Glycine soja). The identification of a dominant susceptible NBS-LRR gene provides insight into the behavior of NBS-LRR proteins and serves as a reminder to breeders that the dominance of an R gene can be influenced by a susceptibility allele.

First Report of Coleosporium clematidis Causing Rust Disease on Clematis patens in Korea.

Clematis patens (Ranunculaceae), often called big-flower clematis, is a perennial plant native to Northeast Asia, including China, Japan, and Korea. This plant is one of the popular ornamental plants because of its large and colorful flower. In Korea, it is widely cultivated for public and private gardening and medicinal purposes. In September of 2021, symptoms of rust disease were found on C. patens at a public park (ca. 30 ha) in Jeonju (35°52'16"N, 127°03'16"E), Korea, where the disease occurred on 80% of C. patens plants (n = 50) surveyed, and disease severity in each affected plant ranged 60 to 90%. Symptoms appeared as light green, vein-limited chlorotic spots on the upper surface of infected leaves, and yellow or orange rust pustules were formed on the corresponding lower surface of leaves. A representative sample was deposited in the Kunsan National University Herbarium (KSNUH1522). Uredinia were yellow or orange, round to ellipsoidal, mostly scattered, and 0.5-1 mm in diameter. Urediniospores were pale yellow, ellipsoid or ovoid, 23.1 to 34.8 × 14.9 to 24.7 (average 29.3 ± 2.7 × 18.8 ± 2.2 μm [mean ± SD], n = 50) μm with a verrucose and hyaline wall of 1.0-2.0 μm thick. The morphological characteristics were similar to those reported for Coleosporium clematidis (Barclay 1889, Hiratsuka et al. 1992). To confirm morphological identification, genomic DNA was extracted from a representative specimen (KSNUH1522). The internal transcribed spacer (ITS) rDNA with primers ITS5-u and ITS4rust (Pfunder and Schürch 2001) and large subunit (LSU) rDNA with primers LRust1R and LRust3 (Beenken et al. 2012) were amplified for sequencing. Two resulting sequences (Acc. Nos. OM200310 for ITS, OM184262 for LSU) were blasted in GenBank. The ITS sequence of the Korean sample differs at a nucleotide with a sequence of C. clematidis from Clematis sp. (KX386005) but at eight nucleotides with other three sequences of C. clematidis (KX386007, KX386008 and KX386010). The LSU sequence differs at a nucleotide from the sequences of C. clematidis from Clematis sp. (KX386039, KX386040, KX386042). In phylogenetic trees of the ITS and LSU sequences, the Korean isolate formed a well-supported clade with the reference sequences of C. clematidis. For a pathogenicity test, urediniospores (1.25 ×106/ml) were harvested from the infected leaves and inoculated onto three healthy C. patens. Three non-inoculated plants served as controls. Inoculated and non-inoculated plants were kept in a plant growth chamber at 22°C, a 16/8 h of light cycle, 80% humidity. After three weeks, all inoculated plants formed yellow rust pustules on the lower surface of leaves, identical to what was previously observed in the field, whereas the control plants remained symptomless. The same pathogen was confirmed from the symptomatic plants, fulfilling Koch's postulates. Based on morphological characteristics, sequence data and pathogenicity test, the causal agent of rust on Clematis patens was identified as C. clematidis. To our knowledge, this is the first report of rust disease caused by C. clematidis on C. patens in Korea and previously recorded only in Japan (Hiratsuka et al. 1992). Coleosporium clematidis has been reported on about 60 species of Clematis in Asia and Africa but has not been reported in Europe and North America (Farr and Rossman 2022). In Korea, Clematis fusca var. violacea was previously reported as a host plant for the causal pathogen (Cho and Shin 2004). Given the high occurrence and severe damage, this disease could be a potential threat to the cultivation of C. patens.

Anthraquinones and their analogues as potential biocontrol agents of rust and powdery mildew diseases of field crops.

BackgroundRusts and powdery mildews are severe fungal diseases of major crops worldwide, including cereals and legumes. They can be managed by chemical fungicide treatments, with negative consequences as environmental pollution and risk for human and animal health. Bioactive natural products could be the safest alternative for pest control. The family of anthraquinones, as well as analogue compounds containing an anthraquinone moiety or some modified anthraquinone rings, has been reported to exhibit certain antibiotic activity. Thus, the potential antifungal activity of some anthraquinones isolated from Ascochyta lentis, was assayed in this study for their effectiveness to reduce rust and powdery mildew diseases on pea and oat. Their effect on fungal development was macro‐ and microscopically assessed on inoculated leaves, and compared to the control achieved by the chemical fungicide (Tetraconazol 12.5% and Azoxystrobin 25%). In addition, the most promising compound was also tested at different concentrations in inoculated whole plants in order to evaluate its preventive and curative potential against fungal infection.ResultsAll metabolites studied strongly reduced the development of rust and powdery mildews in both pea and oat, being pachybasin and lentiquinone C the most effective ones in hampering fungal spore germination and appressoria formation. Some of them also affected post‐penetration events reducing colony size and number of haustoria per colony. Results were confirmed for pachybasin in whole plants assays, showing an efficacy similar to the commercial fungicide to control fungal diseases, both in preventive and curative applications.ConclusionsSome fungal anthraquinones and close metabolites, especially pachybasin, could be very promising molecules with effective potential as antifungal agents against both rust and powdery mildew of both pea and oat. Some structure activity‐relationships feature have also been evaluated. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Emergence of a New Rust Disease of Virginia Creeper (Parthenocissus quinquefolia) through a Host Range Expansion of Neophysopella vitis

Virginia creeper (or five-leaved ivy; Parthenocissus quinquefolia) is one of the most popular and widely grown climbers worldwide. In September 2021, Virginia creeper leaves with typical rust symptom were found in an arboretum in Korea, with severe damage. Globally, there is no record of a rust disease on Virginia creeper. Using morphological investigation and molecular phylogenetic inferences, the rust agent was identified as Neophysopella vitis, which is a rust pathogen of other Parthenocissus spp. including Boston ivy (P. tricuspidata). Given that the two ivy plants, Virginia creeper and Boston ivy, have common habitats, especially on buildings and walls, throughout Korea, and that N. vitis is a ubiquitous rust species affecting Boston ivy in Korea, it is speculated that the host range of N. vitis may recently have expanded from Boston ivy to Virginia creeper. The present study reports a globally new rust disease on Virginia creeper, which could be a major threat to the ornamental creeper.

The gene Sr38 for bread wheat breeding in Western Siberia

Present-day wheat breeding for immunity exploits extensively closely related species from the family Triticeae as gene donors. The 2NS/2AS translocation has been introduced into the genome of the cultivated cereal Triticum aestivum from the wild relative T. ventricosum. It contains the Lr37, Yr17, and Sr38 genes, which support seedling resistance to the pathogens Puccinia triticina Eriks., P. striiformis West. f. sp. tritici, and P. graminis Pers. f. sp. tritici Eriks. & E. Henn, which cause brown, yellow, and stem rust of wheat, respectively. This translocation is present in the varieties Trident, Madsen, and Rendezvous grown worldwide and in the Russian varieties Morozko, Svarog, Graf, Marquis, and Homer bred in southern regions. However, the Sr38 gene has not yet been introduced into commercial varieties in West Siberia; thus, it remains of practical importance for breeding in areas where populations of P. graminis f. sp. tritici are represented by avirulent clones. The main goal of this work was to analyze the frequency of clones (a)virulent to the Sr38 gene in an extended West Siberian collection of stem rust agent isolates. In 2019–2020, 139 single pustule isolates of P. graminis f. sp. tritici were obtained on seedlings of the standard susceptible cultivar Khakasskaya in an environmentally controlled laboratory (Institute of Cytology and Genetics SB RAS) from samples of urediniospores collected on commercial and experimental bread wheat f ields in the Novosibirsk, Omsk, Altai, and Krasnoyarsk regions. By inoculating test wheat genotypes carrying Sr38 (VPM1 and Trident), variations in the purity of (a)virulent clones were detected in geographical samples of P. graminis f. sp. tritici. In general, clones avirulent to Sr38 constitute 60 % of the West Siberian fungus population, whereas not a single virulent isolate was detected in the Krasnoyarsk collection. The Russian breeding material was screened for sources of the stem rust resistance gene by using molecular markers specif ic to the 2NS/2AS translocation. A collection of hybrid lines and varieties of bread spring wheat adapted to West Siberia (Omsk SAU) was analyzed to identify accessions promising for the region. The presence of the gene was postulated by genotyping with specif ic primers (VENTRIUP-LN2) and phytopathological tests with avirulent clones of the fungus. Dominant Sr38 alleles were identif ied in Lutescens 12-18, Lutescens 81-17, Lutescens 66-16, Erythrospermum 79/07, 9-31, and 8-26. On the grounds of the composition of the West Siberian P. graminis f. sp. tritici population, the Sr38 gene can be considered a candidate for pyramiding genotypes promising for the Novosibirsk, Altai, and Krasnoyarsk regions

A molecular approach reveals Tranzschelia discolor as the causal agent of rust on plum and peach in Brazil.

Plum and peach are important crops in the southernmost regions of Brazil and in the majority, fresh fruit producers are small producers, which guarantee their family income. Tranzschelia discolor and T. pruni-spinosae are the etiological agents of rust on Prunus domestica (plum) and P. persica (peach) in Brazil (Mendes and Urben, 2020). The molecular characterization of Tranzschelia specimens revealed different clades that are not attributed to known species, showing the need for taxonomic evaluation of Tranzschelia species in the tropics (Scholler et al. 2014; 2019). As Tranzschelia species reported in Brazil were identified only by morphological characteristics, this study aimed to carry out a survey to verify the etiology of rust on plum and peach based on molecular data. In 2018, rust symptoms in peach and plum trees were observed with maximum severity of 30% and 35%, respectively, in three Brazilian states. Symptoms of plum and peach rust are yellowish-green spots visible on the adaxial side of the leaves and uredia/uredinial sori releasing the brown urediniospores on the abaxial side (Supplementary figure 1). Symptomatic leaves of plum and peach were collected at Curitiba in the states of Paraná (lat. 25°25'47" S and long. 49°16'19" W, altitude of 935 meters) in a research station, Videira in Santa Catarina (lat. 27°00'30" S and long. 51°09'06" W, altitude of 750 meters) in a research station and Paranapanema in São Paulo (lat. 23º23'19" S and long. 48º43'22" W, altitude of 610 meters) in a farmer field, and deposited in the herbarium of the Municipal Botanical Museum of Curitiba (MBM 429790 to 429795). Urediniospores collected on plum and peach leaves were all echinulate, obovoid, orange-brown, and measured 18.0 - 33.5 μm × 10.5 - 20.5 μm (n=150) and 22.5 - 40.0 μm × 11.5 - 20.5 μm (n=150), respectively. The genomic DNA of the urediniospores was extracted for amplification and sequencing of the internal transcribed spacer region (ITS) using primers ITS5-u and ITS4-u (Pfunder et al. 2001). The sequences were deposited (Accession Nos. MT786213 to MT786218) and compared to sequences in the GenBank repository using the BLASTn algorithm. The sequences of ITS showed a high percentage of identity (>99%) with sequences from T. discolor (Accession Nos. AB097449, EU014071, KU712078, KY764179, MH599069, MN545867, DQ995341, DQ354542, and KX985768). Additionally, our isolates clustered with others T. discolor in a Bayesian phylogenetic tree based on ITS sequences (study S26663 deposited in TreeBASE) (Supplementary figure 2). A pathogenicity test was carried out on plants by inoculation of a 1.5 × 105 urediniospores mL-1 suspension on the abaxial side of the leaves. Leaves sprayed with sterile water were used as controls. The plants were incubated in a growth chamber (GC) in the dark for 48 h at 23 °C and maintained with 100% RH to establish infections. The inoculated plants were afterwards kept in the GC at a photoperiod of 12 h under same conditions until 14 days when the symptoms and pathogen structures were observed to all six isolates. Control leaves remained symptomless. Tranzschelia discolor infect plants in the genus Prunus, including almond, apricot, nectarine, cherry, peach, and plum (Farr and Rossman 2021). As T. pruni-spinosae was not found, T. discolor is probably the prevalent species in the main regions of Brazil. This information reveals T. discolor as the causal agent of plum and peach rust in Brazil and helps to understand the distribution of this disease in tropics or worldwide.

Investigating hyperparasites as potential biological control agents of rust pathogens on cereal crops

Rust pathogens cause damage to cereal crops around the world, leading to reduced yield and profit. Current methods of rust control include fungicides, resistant cultivars, and preventative agronomic practices. Some hyperparasites are antagonists of plant pathogens and may provide a potential method of biocontrol against increasingly virulent strains of rust. Very little is known about the mechanism of inhibition of rust growth by hyperparasites, however, isolation of new strains and subsequent characterisation may reveal new treatment strategies for the control of rust. Here we report the isolation of six new fungal hyperparasites and their effects on the development of three Puccinia rust pathogens were examined in vitro, to determine the potential of each as biocontrol agents of rust. Cut-leaf sections of rust-susceptible wheat, barley and oat cultivars were treated with fungal hyperparasite conidia prior to infection with the rust species; Puccinia triticina, P. hordei, and P. coronata f. sp. avenae, respectively. Inhibition of rust spore germination tests were also performed on water agar plates co-inoculated with the isolates. In leaf sections, rust pustule number was significantly (P < 0.01) lower for all six isolates tested: Penicillium brevicompactum, Clonostachys rosea, Simpicillium aogashimaense, Neoascochyta sp., Lecanicillium psalliotae and Epicoccum nigrum. The results of these experiments suggest that the mechanisms underlying the reduction in pustule number could include one or more of the processes of direct parasitism, antagonism by antibiosis, competition, and/or induction of host plant resistance.

Leucotelium cerasi (Bérenger) Tranzschel 1935, novel pathogen for mycobiota in Serbia

During the field studies on a strictly protected plant species Eranthis hyemalis (winter aconite) in Serbia, it was noticed that certain individuals were infected by some species of parasitic fungus. According to the structure of spermogonia and aecia, as well as distinctive types of spores recorded in infected leaves of winter aconite, the fungus was determined as Leucotelium cerasi, known as a causative agent of rust in E. hyemalis and Prunus species. Although it was first recorded in Serbia in Prunus spinosa as a host (area of Valjevo in 1935), the appearance of this phytopathogen was recorded in foliar tissue of E. hyemalis at four localities in Eastern Serbia, near Knjazevac (Podvis, Golemi Kamen, and Ploca) and Zajecar (Zmijanac). It was concluded that plants in natural populations of host species were infected to a very high degree, as the number of infected plants reached half of the total number of individuals in all studied populations. Further research is neces?sary to determine to what extent this fungus is threatening the survival of host populations and then implement appropriate protection measures.

Candidate Effectors From Uromyces appendiculatus, the Causal Agent of Rust on Common Bean, Can Be Discriminated Based on Suppression of Immune Responses.

Rust fungi are devastating pathogens for several important crop plants. The biotrophic lifestyle of rust fungi requires that they influence their host plants to create a favorable environment for growth and reproduction. Rust fungi secrete a variety of effector proteins that manipulate host target proteins to alter plant metabolism and suppress defense responses. Because of the obligate biotrophic lifestyle of rust fungi, direct evidence for effector function is difficult to obtain, and so suites of experiments utilizing expression in heterologous systems are necessary. Here, we present results from a yeast cell death suppression assay and assays for suppression of PAMP-triggered immunity (PTI) and effector triggered immunity (ETI) based on delivery of effectors through the bacterial type III secretion system. In addition, subcellular localization was tested using transient expression of GFP fusion proteins in Nicotiana benthamiana through Agrobacterium infiltration. We tested 31 representative effector candidates from the devastating common bean rust pathogen Uromyces appendiculatus. These effector candidates were selected based on features of their gene families, most important lineage specificity. We show that several of our effector candidates suppress plant defense. Some of them also belong to families of effector candidates that are present in multiple rust species where their homologs probably also have effector functions. In our analysis of candidate effector mRNA expression, some of those effector candidates that gave positive results in the other assays were not up-regulated during plant infection, indicating that either these proteins have functions at multiple life stages or that strong up-regulation of RNA level in planta may not be as important a criterion for identifying effectors as previously thought. Overall, our pipeline for selecting effector candidates based on sequence features followed by screening assays using heterologous expression systems was successful in discriminating effector candidates. This work lays the foundation for functional characterization of U. appendiculatus effectors, the identification of effector targets, and identification of novel sources for resistance in common bean.

Pucciniastrum minimum is the causal agent of rust on blueberries in New Zealand

The causal agent of rust on blueberries in New Zealand was determined by molecular and morphological analyses as Pucciniastrum minimum rather than Naohidemyces vacciniorum as first reported in 2004.

Severity of rust (Olivea tectonae) in different clones of teak in northern Mato Grosso

The fungus Olivea tectonae , has been increasing attention from different countries of course have teak or commercial plantations with the species, as it causes severe defoliation of plants, contributing to the reduction of production. The objective was to monitor different teak clones, with five months in Sinop / MT, with respect to the fungus O. tectonae , causal agent of rust. The study of disease progress was made between the months of May 2009 to July 2010, evaluating the severity visually in three regions of the plant: upper, middle and lower. We analyzed ten different clones C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 and, after completion of data collection built up the area under the disease progress curve (AUDPC). The results showed that clone C7 was most likely at the top (AAPCD 35,45) and clone C1 was the most resistant (AACPD 22,37). The C9, C8 and C10 clones are statistically equal, more likely in the middle region (AAPCD 6.332,02; 5.873,34; 5.759,75, respectively) and C5 more resistant clone in this region (AACPD 1.872,70). In the lower region the clone C5 was the toughest (AACPD 5.691,06) and the C9 clone was the most likely (AACPD 15.746,73). In the analysis of the entire plant, the clone C5 was tougher (AACPD 27.603.889,00) and C9 clones C8 and C10 were statistically equal, proving to be the most susceptible to rust (AACPD 78.872.378,00; 68.335.115,00 e 65.686.893,00 respectively).

Molecular-genetic approaches to studying wheat leaf rust populations

Population studies of the leaf rust agent Puccinia triticina Erikss. have a long-time history. This review describes the traditional phytopathological and modern molecular methodological approaches used in P. triticina studies. The results of the analysis of P. triticina Russian populations according with virulence and intrapopulation and interpopulation diversity studies of the pathogen by DNA polymorphism are summarized. The advantages and disadvantages of RAPD, AFLP and SSR analyses for studies of P. triticina populations are discussed. The original results of analysis of P. triticina populations using RAPD and SSR markers are presented. Since the middle of 2010, new SNP markers have been developed for coevolution studies in P. triticina populations existed on the common and durum wheats. The possibility and perspective of using a new methodological approach for assessing the degree of phylogenetic relationship between Derbent isolates of P. triticina obtained from Triticum sp. and Aegilops sp. different ploidy are discussed. Prospects for the creation and practical use of new molecular genetic diagnostic systems for monitoring populations, tracking the emergence of new races, their distribution and migration are presented.

Genome size estimates for six rust (Pucciniales) species

Rust fungi (Basidiomycota, Pucciniales), one of the largest groups of phytopathogenic organisms, are characterised by host specialisation, biotrophy, complex life cycles and enlarged genomes. In this work we have used flow cytometry to determine the genome size of six rust species, Melampsora pulcherrima, Puccinia behenis, P. cichorii, P. pimpinellae, P. vincae and Uromyces dianthi, the causal agents of rust on Mercurialis annua, Silene latifolia, Cichorium intybus, Pimpinella villosa, Vinca major and Dianthus caryophyllus, respectively. With results ranging between 182.1 and 566.4 Mbp/1C, this study has contributed to the knowledge of genome sizes in the order Pucciniales, reinforcing this group as the one with the largest average genome size among fungi, with 335.6 Mbp/1C. By comparing genome sizes and their variability across the fungal kingdom, this study has contributed for understanding the patterns of genome size distribution along the fungal phylogeny, suggesting links between biological specificities and genome sizes. In particular, genome sizes of rust fungi vary greatly within genera, but also differ sharply from other non- Pucciniales orders in the Pucciniomycotina, suggesting that genome size variation may be an active element shaping the evolution of rust fungi.

Winter garlic rust (Puccinia spp.) rate under organic and conventional production conditions

Due to low requirements for fertilizers and pesticides, garlic is a valuable crop in organic systems, although production may be hampered by diverse pathogens. In recent years, garlic rust (Puccinia spp.) has been increasingly present in our agro-ecological climate, developing into a significant problem for garlic production. The aim of the study was twofold: i) to monitor winter garlic rust rate in organic and in conventional production, and ii) to monitor genotype sensitivity to the pathogen in both production systems. Trials were conducted in 2012/2013 in Backi Petrovac, Serbia at the Institute of Field and Vegetable Crops in Novi Sad, and included 30 genotypes planted in organic and conventional field, simultaneously. Disease severity was evaluated visually, using a scoring system between zero and five. Overall average infection intensity score in conventional plots was 1.18, and in organic plots 0.79. There was no statistically significant difference between infection intensity in conventional versus organic plots. Nevertheless, reactions of certain genotypes to the causal agents of rust differed across organic and conventional plots ranging from no apparent infection symptoms in organic to severe symptoms in conventional plots.

УСТОЙЧИВОСТЬ ТРИТИКАЛЕ К ОСНОВНЫМ ВОЗБУДИТЕЛЯМ БОЛЕЗНЕЙ, РАСПРОСТРАНЕННЫМ В СЕВЕРО-ЗАПАДНОМ РЕГИОНЕ РОССИЙСКОЙ ФЕДЕРАЦИИ

The modern triticale varieties have high feed advantages, they have a good tolerance to difficult environments and they are resistant to majority of phytopathogens. For the period of 2005-2006 phytosanitary monitoring for the triticale samples of different ecologo-geographic origin with spring (327 samples) and winter (37 samples) type of development from N.I. Vavilov All-Russian Scientific Research Institute of Plant Growing on the resistance to the basic wheat pathogens of Northwest region of the Russian Federation (brown and yellow rust, wheat leaf blotch, powdery mildew) was carried out. In addition, the authors determine the duration of interphase periods, the height of plants, the mass of 1000 grains. The pathogen of powdery mildew does not develop on samples of triticale. The maximal number of triticale samples, introduced from the European part of the former Soviet Union (Ukraine, Belarus) was characterized by absence of defeat symptoms by brown rust and wheat leaf blotch agents. Pathogenesis of the yellow rust agent was not found on the triticale samples, received from Central Asia, Northern Europe, Australia, South America, Asia and Africa. As was revealed, the greatest degree the attribute of triticale origin influenced on wheat leaf blotch pathogenesis, in the least – on brown and yellow rusts pathogenesis. As was revealed, the criterion of a triticale origin influenced on wheat leaf blotch pathogenesis in the greatest degree, and in the least – on brown and yellow rusts. In the greater degree the plants development type affect the wheat leaf blotch pathogenesis on triticale samples of the Russian selection and in smaller on triticale samples, received from European part of Former USSR, Northern Europe, East Europe, Central Europe.

TRITICALE RESISTANCE TO THE MAIN PHYTOPATHOGENIC ORGANISMS OF NORTHWEST REGION OF THE RUSSIAN FEDERATION

The modern triticale varieties have high feed advantages, they have a good tolerance to difficult environments and they are resistant to majority of phy-topathogens. For the period of 2005-2006 phytosanitary monitoring for the triticale samples of different ecologo-geographic origin with spring (327 samples) and winter (37 samples) type of development from N.I. Vavilov All-Russian Scientific Research Institute of Plant Growing on the resistance to the basic wheat patho-gens of Northwest region of the Russian Federation (brown and yellow rust, wheat leaf blotch, powdery mildew) was carried out. In addition, the authors deter-mine the duration of interphase periods, the height of plants, the mass of 1000 grains. The pathogen of powdery mildew does not develop on samples of triticale. The maximal number of triticale samples, introduced from the European part of the former Soviet Union (Ukraine, Belarus) was characterized by absence of de-feat symptoms by brown rust and wheat leaf blotch agents. Pathogenesis of the yellow rust agent was not found on the triticale samples, received from Central Asia, Northern Europe, Australia, South America, Asia and Africa. As was revealed, the greatest degree the attribute of triticale origin influenced on wheat leaf blotch pathogenesis, in the least – on brown and yellow rusts pathogenesis. As was revealed, the criterion of a triticale origin influenced on wheat leaf blotch pathogenesis in the greatest degree, and in the least – on brown and yellow rusts. In the greater degree the plants development type affect the wheat leaf blotch pathogenesis on triticale samples of the Russian selection and in smaller - on triticale samples, received from European part of Former USSR, Northern Europe, East Europe, Central Europe. Keywords: triticale, cereal crop diseases, leaf rust, yellow rust, wheat leaf blotch, powdery mildew.

Development of Electric Rust Preventive Machining Method – Optimization of Water Recycle System

In production site, machining fluid (cutting oil, grinding fluid) is used. It contains several chemicals that are oil, surface active agent, and extreme pressure agent, anti rust agent and so on. Waste fluid disposal which is incineration etc. is necessary and arise huge cost and environmental load. In addition, workers health hazard is concerned for several chemicals while machining. In this investigation, new water machining method system (electric rust preventive machining method system) that uses only water as machining fluid for solving of conventional machining fluid problems is developed. In particularly, this paper mentions optimization of used machining water recycle on purification rate and refined water flow quantity in developed water recycle system. Therefore, high speed adjustment test liquid equipment is developed for stable experimental condition for evaluation. Test liquid turbidity is random for sludge particle and simple filter decreases this fluctuation. However, water recycle system is aimed for constant refined output despite fluctuation of input dirty water, and it is achieved. The optimized refined water flow quantity is 13.3 L/min at 1.0 MPa from viewpoint of purification on iron, turbidity, colour, conductivity and flow rate and purification load for reverse osmosis membrane.

Development of Electric Rust Preventive Machining Method - Improvement of Electric Rust Preventive Chip Sedimentation System

The machining (cutting, grinding etc.) is conducted in manufacturing. Machining fluid (cutting oil, grinding fluid) that consists of oil, surface active agent, and extreme pressure agent, anti rust agent etc. is used. It improves machining performance, but it needs waste fluid disposal that is incineration or coagulative precipitation and so on. It causes huge cost and environmental load. Furthermore, it is afraid of workers health hazard for several chemicals while machining. Therefore, the electric rust preventive machining method system (water machining) is proposed and developed. This method uses only harmless water (tap water etc.) as machining fluid. In this paper, improvement of electric rust preventive chip sedimentation system that is part of water recycle system which is used for machining water purification and re-use. On long time (3 days) preservation of iron chip in water, decreasing of rust and turbidity is examined. Improved electric rust preventive chip sedimentation system is equipped simple circulation filter unit newly and its effectiveness is clarified. When many quantity of iron powder (3kg) likened to actual sludge is sunken in sedimentation water tank, if electric rust prevention and simple circulation filter activated, turbidity and colour would be decreased greatly. Therefore, it is expected that purification load of next part of filters is decreased and life-time of filter and system will be prolonged.