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BACKGROUND: Glyphosate is a widely used broad-spectrum herbicide. Recent studies in glyphosate-resistant (GR) crops have shown that, in addition to its herbicidal activity, glyphosate exhibits activity against fungi, thereby providing disease control benefits. In GR wheat, glyphosate has shown both preventive and curative activities against Puccinia striiformis f. sp. tritici (Erikss) CO Johnston and Puccinia triticina Erikss, which cause stripe and leaf rusts respectively. RESULTS: Laboratory studies confirmed earlier observations that glyphosate has activity against Phakopsora pachyrhizi Syd & P Syd which causes Asian soybean rust (ASR) in GR soybeans. The results showed that glyphosate at rates between 0.84 and 1.68 kg ha(-1) delayed the onset of ASR in GR soybeans. However, field trials conducted in Argentina and Brazil under natural infestations showed variable ASR control from application of glyphosate in GR soybeans. Further field studies are ongoing to define the activity of glyphosate against ASR. CONCLUSIONS: These results demonstrate the disease control activities of glyphosate against rust diseases in GR wheat and GR soybeans. 相似文献
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Belinelli Eduardo Oliveira Fantin Lucas Henrique Canteri Marcelo Giovanetti Braga Karla Cirilo Eliandro Rodrigues Romeiro Neyva Maria Lopes Natti Paulo Laerte 《European journal of plant pathology / European Foundation for Plant Pathology》2022,163(4):979-990
European Journal of Plant Pathology - Phakopsora pachyrhizi is a biotrophic fungus that needs living plant tissue in order to survive. The fungus causes Asian rust on soybean and costs billions of... 相似文献
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Yuichi Yamaoka 《Journal of General Plant Pathology》2014,80(5):375-388
Rust fungi are obligate plant parasites belonging to the order Pucciniales; they comprise about 7,800 species throughout the world. Some species seriously damage crops, vegetables, fruits and trees. Of these species, wheat stem rust (Puccinia graminis f. sp. tritici), Asian soybean rust (Phakopsora pachyrhizi) and myrtle rust (Puccinia psidii) have recently become major concerns worldwide, and this review, discusses recent rust disease outbreaks of Asian soybean rust and myrtle rust. Both rusts have very wide host ranges. Asian soybean rust has spread from its original region of distribution (eastern Asia) to many areas of soybean cultivation around the world. Myrtle rust is a new disease in areas where host plants were first introduced and has spread to other parts of the world including the areas where the host plants are indigenous. New diseases of economically important plants can occur by host shifts from wild host plants or host jumps from phylogenetically unrelated plant species. Recent advances in molecular phylogenetic studies have contributed to a revision of rust taxonomy. Molecular phylogenetic analyses, together with precise morphological observations and inoculation experiments, have identified taxonomic groups among populations that are morphologically very similar. Systematic, ecological and other basic biological studies of rust fungi in both cultivated and wild host plants are very important for developing methods to control rust diseases. Recent changes in the International Code of Botanical Nomenclature will surely affect the systematics of rust fungi. 相似文献
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André Costa da Silva Paulo Estev?o de Souza José Eduardo Brasil Pereira Pinto Bruno Marques da Silva Douglas Carvalho Amaral Eudes de Arruda Carvalho 《European journal of plant pathology / European Foundation for Plant Pathology》2012,134(4):865-871
The objective of the work was to evaluate the effect of essential oils as a preventive treatment to control Asian soybean rust. Initially the fungitoxic effect of the essential oils of Hyptis marrubioides, Aloysia gratissima and Cordia verbenacea was tested on the urediniospores of Phakopsora pachyrhizi, through in vitro tests. The in vivo test was set up in a greenhouse, using cultivar MGBR-46. The treatments consisted of the three oils at different concentrations, a fungicide based on pyraclostrobin + epoxyconazole and a control. To verify the potential of the essential oils in preventive treatment, inoculation was conducted at 0, 6, 12 and 24?h intervals, after application of the treatments. All treatments inhibited 100% of Phakopsora pachyrhizi germination. In the in vivo test, it was observed that all of the oils were efficient in controlling soybean rust, by preventive treatment, mainly at the higher concentrations. Efficiency of the oils was reduced with the increase of the interval between the application of the treatments and the onset of the pathogen. The essential oils, at the tested dosages, were not as efficient as the pyraclostrobin + epoxyconazole based fungicide. 相似文献
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嘧菌酯是防治大豆锈病的重要杀菌剂,明确嘧菌酯在大豆上的残留规律是一项亟待开展的课题。本研究采用超高效液相色谱-串联质谱 (UPLC-MS/MS) 技术,建立了大豆种植体系中茎、叶、籽粒及土壤中嘧菌酯的残留分析方法,定量限达0.005 mg/kg。在田间试验点基础上,明确了安徽、山东和吉林3个试验点嘧菌酯在大豆上的沉积与降解规律,发现250 g/L嘧菌酯悬浮剂在施用后主要沉积在大豆叶片中,沉积量由北向南呈逐渐降低趋势,嘧菌酯在上部茎叶中降解速率较快,地区间无明显差异;比较了不同剂量嘧菌酯与大豆锈病防效之间的关系,同时给出了残留量,得到了嘧菌酯的最低有效防控剂量为225 g/hm2。本研究成果对指导嘧菌酯在大豆生产中的科学使用以及对大豆上农药减量实践具有重要意义。 相似文献
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The origin and genetic diversity of the causal agent of Asian soybean rust,Phakopsora pachyrhizi,in South America 
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下载免费PDF全文 V. R. Jorge M. R. Silva E. A. Guillin M. C. M. Freire I. Schuster A. M. R. Almeida L. O. Oliveira 《Plant pathology》2015,64(3):729-737
A sequence‐based approach was used to investigate molecular genetic variations in Phakopsora pachyrhizi, an obligate biotrophic pathogen that causes Asian soybean rust. In Argentina, the samples came from uredinium‐bearing leaves taken from 11 soybean fields; in Brazil, the samples comprised urediniospores from leaves of 10 soybean genotypes that had been grown in three experimental stations during two growing seasons. PCR‐based cloning techniques were used to generate DNA sequences for two gene regions and alignments were supplemented with data from GenBank. A total of 575 sequences for the internal transcribed spacer region (18 ribotypes) and 160 partial sequences for a housekeeping gene encoding ADP‐ribosylation factor (10 haplotypes) were obtained. Ribotype accumulation curves predicted that about 20 bacterial clones would recover 5–6 ribotypes (c. 70–80% of the total molecular variation) per locality. The samples from the three experimental stations in Brazil displayed most (14 out of 16) ribotypes found worldwide; the lack of genetic structure and differentiation at a diverse geographic scale suggests that both local and distant sources provide airborne inoculum during disease establishment. Soybean genotypes with resistance genes for the Asian soybean rust did not decrease the molecular genetic variation of fungal populations. 相似文献
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ABSTRACT Although Asian soybean rust occurs in a broad range of environmental conditions, the most explosive and severe epidemics have been reported in seasons with warm temperature and abundant moisture. Associations between weather and epidemics have been reported previously, but attempts to identify the major factors and model these relationships with field data have been limited to specific locations. Using data from 2002-03 to 2004-05 from 34 field experiments at 21 locations in Brazil that represented all major soybean production areas, we attempted to identify weather variables using a 1-month time window following disease detection to develop simple models to predict final disease severity. Four linear models were identified, and these models explained 85 to 93% of variation in disease severity. Temperature variables had lower correlation with disease severity compared with rainfall, and had minimal predictive value for final disease severity. A curvilinear relationship was observed between 1 month of accumulated rainfall and final disease severity, and a quadratic response model using this variable had the lowest prediction error. Linear response models using only rainfall or number of rainy days in the 1-month period tended to overestimate disease for severity <30%. The study highlights the importance of rainfall in influencing soybean rust epidemics in Brazil, as well as its potential use to provide quantitative risk assessments and seasonal forecasts for soybean rust, especially for regions where temperature is not a limiting factor for disease development. 相似文献
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Molecular mapping of Asian soybean rust resistance in soybean landraces PI 594767A,PI 587905 and PI 416764 下载免费PDF全文
下载免费PDF全文 M. M. Hossain H. Akamatsu M. Morishita T. Mori Y. Yamaoka K. Suenaga R. M. Soares A. N. Bogado A. J. G. Ivancovich N. Yamanaka 《Plant pathology》2015,64(1):147-156
Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, is one of the most serious diseases of soybean. The soybean landraces PI 594767A, PI 587905 and PI 416764 previously showed high levels of resistance to a wide range of ASR fungus, while the genetic basis of the resistance has yet to be understood. In this study, the ASR resistance loci were mapped using three independent mapping populations, POP‐1, POP‐2 and POP‐3 derived from crosses BRS184 × PI 594767A, BRS184 × PI 587905 and BRS184 × PI 416764, respectively. In each population, the resistance to ASR segregated as a single gene, but the resistance was dominant in PI 594767A and PI 587905 and incompletely dominant in PI 416764. The resistance genes from both PI 594767A and PI 587905 were mapped on chromosome 18 corresponding to the same location as known resistance locus Rpp1. Quantitative trait locus (QTL) analysis performed on POP‐3 identified the putative ASR resistance locus in PI 416764 on the defined region of chromosome 6 where Rpp3 was located. The QTLs detected by the mapping explained about 67–72% of the phenotypic variation in POP‐3. Cluster analysis based on disease reactions to 64 ASR populations demonstrated the presence of at least two types of functional resistant Rpp1 alleles: strong and weak allele(s), e.g. soybean accession PI 594767A and PI 587905 carry the strong resistant Rpp1 allele(s). Introducing or pyramiding strong Rpp1 allele(s) in elite soybean cultivars is expected to be useful against the South American rust population. 相似文献
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Although considerable information exists regarding the importance of moisture in the development of soybean rust, little is known about the influence of temperature. The purpose of our study was to determine whether temperature might be a significant limiting factor in the development of soybean rust in the southeastern United States. Soybean plants infected with Phakopsora pachyrhizi were incubated in temperature-controlled growth chambers simulating day and night diurnal temperature patterns representative of the southeastern United States during the growing season. At 3-day intervals beginning 12 days after inoculation, urediniospores were collected from each plant and counted. The highest numbers of urediniospores were produced when day temperatures peaked at 21 or 25°C and night temperatures dipped to 8 or 12°C. When day temperatures peaked at 29, 33, or 37°C for a minimum of 1 h/day, urediniospore production was reduced to 36, 19, and 0%, respectively, compared with urediniospore production at the optimum diurnal temperature conditions. Essentially, no lesions developed when the daily temperature high was 37°C or above. Temperature data obtained from the National Climatic Data Center showed that temperature highs during July and August in several southeastern states were too high for significant urediniospore production on 55 to 77% of days. The inhibition of temperature highs on soybean rust development in southeastern states not only limits disease locally but also has implications pertaining to spread of soybean rust into and development of disease in the major soybean-producing regions of the Midwestern and northern states. We concluded from our results that temperature highs common to southeastern states are a factor in the delay or absence of soybean rust in much of the United States. 相似文献
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Abstract Greenhouse and field experiments were conducted to study the preference of two scarabaeid beetles, Anomala cupripes Hope and A. expansa Bates, for soybean plants at various growth stages and the potential use of a trap cultivar to control these pests. Insects preferred to feed on 6–9‐week‐old plants compared to younger ones. This may be due to more foliage on the older plants, which is a source of food and a shelter for the insect from direct sunlight. Planting a cultivar with more foliage as a trap cultivar between rows of the agronomic cultivar attracted the beetles and reduced the infestation of the agronomic cultivar. The optimum distance to plant such a trap cultivar between rows of agronomic cultivar needs to be determined for each location. 相似文献
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ABSTRACT Soybean rust, Phakopsora pachyrhizi, has been considered a threat to the production of the U.S. soybean, Glycine max. During the past decade, this disease gradually spread to Africa, South America, and recently to the United States. Previous soybean rust risk assessments with an assumption of availability of spores early in a season showed that weather conditions (dew and temperature) during a growing season, in general, are suitable for disease development in U.S. soybean-growing regions. Predicting the time of rust appearance in a field is critical to determining the destructive potential of rusts, including soybean rust. In this study, comparative epidemiology was used to assess likely rust incipient time in four locations within the U.S. Soybean Belt from south to north: Baton Rouge, LA; Charlotte, NC; Indianapolis, IN; and Minneapolis, MN. Temperature effects on the infection cycle of five rusts occurring in the Midwest were evaluated using a general disease model. The likely incipient times were examined with the modeling results. Among the rusts studied, early-appearing rusts had suitable conditions for development earlier in a season. However, a lag period of several weeks to more than 3 months was found from the time when conditions are suitable for a rust to develop or when hosts are available to the time when the rust was detected in fields. Length of the lag period differed among the rust species examined. If nature of long-distance dispersal is not significantly different among the rusts, implications of our study to the expected seasonal soybean rust incipience in fields lead to two possible scenarios: (i) average appearance time of soybean rust across the Soybean Belt should be somewhere between appearance times of common corn rust and southern corn rust, and (ii) with late appearance of the disease, late-planted soybean in the south has greater risk. 相似文献
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防控大豆病害的农药登记现状及发展对策 总被引：1，自引：0，他引：1
在分析大豆生产和病害危害的基础上,对我国大豆生产中防控病害的农药登记现状进行了统计分析。目前我国大豆上登记的杀菌剂有效成分12个,产品64个,分别占61个总有效成分数量的19.67%,306个总产品数量的20.92%;其中福美双、多菌灵和克百威不同配比的混配产品在2002年前占登记杀菌剂产品的82%以上;登记的靶标病害包括大豆根腐病、紫斑病、孢囊线虫病、锈病和病毒病等5种,占国内已经报道的33种病害总数的15.15%。目前丁硫克百威、毒死蜱和阿维菌素等替代高毒的克百威与福美双、多菌灵混配的种衣剂产品登记发展较快;甲氧基丙烯酸酯类杀菌剂嘧菌酯和三唑类杀菌剂戊唑醇、苯醚甲环唑和丙环唑先后取得登记,对防控大豆锈病等具有较好效果。建议加速具有针对性、超前性的杀菌剂新有效成分及新产品的研究开发,推进"小范围使用登记",促进我国大豆病害防控的可持续发展。 相似文献
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Junia Vianna Corrêa da Silva Fernando César Juliatti João Renato Vaz da Silva Fernanda Carvalho Barros 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(3):409-418
Soybean rust is caused by an obligate parasite (Phakopsora pachyrhizi) which has spread in Brazil in each new season since 2001 and, despite the efforts to control the disease, losses have occurred
every year. Its control demands several tactics amongst which chemical control with fungicides is the main method and remains
indispensable. Control strategies such as the use of cultivars with partial resistance are desirable, but are not yet commercially
available. The present study analyzed the existing differences in the reactions of short, medium and long cycle soybean cultivars
against Asian rust and their responses to fungicide sprays. The experiment was conducted at Uberlandia-MG, Brazil, under field
conditions from December 2007 to May 2008, in the Syngenta Seeds Experimental Station. The high pressure of the disease in
the experiment simulated the natural pressure that the disease often reaches in Brazil. The studied variables were: visual
severity (percentage of infected leaf area), percentage defoliation and productivity (kg ha−1). Disease severity was expressed as AUDPC (area under disease progress curve). Variance analysis and comparison of means
by the Tukey test (5% significance) were done for all variables studied. Significant differences were observed between cultivar
effects and chemical control programs. The results obtained here indicate that the cultivars M-Soy 8199RR and Emgopa 315RR
were less susceptible to disease, and that a control program termed “monitoring” (in which the appearance of new pustules
of the pathogen were monitored to make the decision at each fungicide spray) was the most effective. 相似文献
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Kendrick MD Harris DK Ha BK Hyten DL Cregan PB Frederick RD Boerma HR Pedley KF 《Phytopathology》2011,101(5):535-543
ABSTRACT Asian soybean rust (ASR) is an economically significant disease caused by the fungus Phakopsora pachyrhizi. The soybean genes Rpp3 and Rpp?(Hyuuga) confer resistance to specific isolates of the pathogen. Both genes map to chromosome 6 (Gm06) (linkage group [LG] C2). We recently identified 12 additional soybean accessions that harbor ASR resistance mapping to Gm06, within 5 centimorgans of Rpp3 and Rpp?(Hyuuga). To further characterize genotypes with resistance on Gm06, we used a set of eight P. pachyrhizi isolates collected from geographically diverse areas to inoculate plants and evaluate them for differential phenotypic responses. Three isolates elicited different responses from soybean accessions PI 462312 (Ankur) (Rpp3) and PI 506764 (Hyuuga) (Rpp?[Hyuuga]). In all, 11 of the new accessions yielded responses identical to either PI 462312 or Hyuuga and 1 of the new accessions, PI 417089B (Kuro daizu), differed from all others. Additional screening of Hyuuga-derived recombinant inbred lines indicated that Hyuuga carries two resistance genes, one at the Rpp3 locus on Gm06 and a second, unlinked ASR resistance gene mapping to Gm03 (LG-N) near Rpp5. These findings reveal a natural case of gene pyramiding for ASR resistance in Hyuuga and underscore the importance of utilizing multiple isolates of P. pachyrhizi when screening for ASR resistance. 相似文献
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Simulation of apparent infection rate to predict severity of soybean rust using a fuzzy logic system
ABSTRACT Few biologically based models to assess the risk of soybean rust have been developed because of difficulty in estimating variables related to infection rate of the disease. A fuzzy logic system, however, can estimate apparent infection rate by combining meteorological variables and biological criteria pertinent to soybean rust severity. In this study, a fuzzy logic apparent infection rate (FLAIR) model was developed to simulate severity of soybean rust and validated using data from field experiments on two soybean cultivars, TK 5 and G 8587. The FLAIR model estimated daily apparent infection rate of soybean rust and simulated disease severity based on population dynamics. In weekly simulation, the FLAIR model explained >85% of variation in disease severity. In simulation of an entire epidemic period, the FLAIR model was able to predict disease severity accurately once initial values of disease severity were predicted accurately. Our results suggest that a model could be developed to determine apparent infection rate and an initial value of disease severity in advance using forecasted weather data, which would provide accurate prediction of severity of soybean rust before the start of a season. 相似文献
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For over 30 years, it has been known that Phakopsora pachyrhizi is unusual in that it penetrates from urediniospores directly through the leaf cuticle without entering stomates. This unusual mode of penetration suggests that disease resistance mechanisms might exist for soybean rust that do not exist for most rust diseases. As a result, we decided to conduct a histological study using transmission electron microscopy to further elucidate the mechanisms of penetration and early establishment of P. pachyrhizi in soybean leaves. Based on our study, it was concluded that P. pachyrhizi utilizes primarily mechanical force, perhaps with the aid of digestive enzymes, to penetrate the cuticle on the leaf surface. However, the lack of deformation lines in micrographs indicated that digestive enzymes, without mechanical force, are used by the penetration hypha to penetrate the outer and inner epidermal cell walls. Digestive enzymes, again indicated by the lack of deformation lines, are used by haustorial mother cells to breach the walls of mesophyll cells to form haustoria. The possibility exists for eventual determination of the precise roles of pressure and digestive enzymes in the development of soybean rust and elucidation of some of the determinants of resistance and susceptibility to this important plant disease. 相似文献