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1
GILLIGAN, C. A. "Comparison of disease progress curves." New Phytologist 115, no. 2 (June 1990): 223–42. http://dx.doi.org/10.1111/j.1469-8137.1990.tb00448.x.
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McRae, K. B. "An Index for Cultivar Resistance Based on Disease Progress Curves." Phytopathology 77, no. 8 (1987): 1181. http://dx.doi.org/10.1094/phyto-77-1181.
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SWEETMORE, A., S. A. SIMONS, and M. KENWARD. "Comparison of disease progress curves for yam anthracnose (Colletotrichum gloeosporioides)." Plant Pathology 43, no. 1 (February 1994): 206–15. http://dx.doi.org/10.1111/j.1365-3059.1994.tb00572.x.
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Knudsen, G. R., C. S. Johnson, and H. W. Spurr. "Use Of a Simulation Model to Explore Fungicide Strategies for Control of Cercospora Leafspot of Peanut1." Peanut Science 15, no. 1 (January 1, 1988): 39–43. http://dx.doi.org/10.3146/i0095-3679-15-1-11.
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Abstract A sub-model describing persistence and efficacy of chlorothalonil fungicide was incorporated into a computer simulation model of Cercospora leafspot of peanut. The resultant model was validated using independent data sets from field trials over a two-year period. Predicted disease progress curves and area under the disease progress curve for different fungicide application schedules and rates were compared with field observations. The model was then used to compare predicted disease severity and area under the disease progress curve (AUDPC) for a calendar spray schedule vs a leafspot advisory program under different weather conditions. Predicted disease severity levels and area under disease progress curves were similar for advisory and calendar spray schedules. Results were insensitive to changes in parameters describing fungicide persistence or efficacy. The model described herein is a good estimator of the combined effects of weather and chlorothalonil treatments on disease progress, effectively ranks treatments or environmental conditions in terms of their effect on leafspot, and provides a basis for comparison of fungicide scheduling strategies. The simulation model predicted AUDPC more accurately than end-of-season disease, and AUDPC is a more reliable indicator of the effect of peanut leafspot disease on yield loss. Simulation experiments will be useful in optimizing fungicide or biocontrol strategies for long-term financial benefit to growers.
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Hau, B. "Mathematical Functions to Describe Disease Progress Curves of Double Sigmoid Pattern." Phytopathology 83, no. 7 (1993): 928. http://dx.doi.org/10.1094/phyto-83-928.
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Godoy, Cláudia V., Lílian Amorim, Armando Bergamin Filho, Herbert P. Silva, Willian J. Silva, and Richard D. Berger. "Temporal progress of southern rust in maize under different environmental conditions." Fitopatologia Brasileira 28, no. 3 (June 2003): 273–78. http://dx.doi.org/10.1590/s0100-41582003000300008.
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The progress of the severity of southern rust in maize (Zea mays) caused by Puccinia polysora was quantified in staggered plantings in different geographical areas in Brazil, from October to May, over two years (1995-1996 and 1996-1997). The logistic model, fitted to the data, better described the disease progress curves than the Gompertz model. Four components of the disease progress curves (maximum disease severity; area under the disease progress curve, AUDPC; area under the disease progress curve around the inflection point, AUDPCi; and epidemic rate) were used to compare the epidemics in different areas and at different times of planting. The AUDPC, AUDPCi, and the epidemic rate were analyzed in relation to the weather (temperature, relative humidity, hours of relative humidity >90%, and rainfall) and recorded during the trials. Disease severity reached levels greater than 30% in Piracicaba and Guaíra in the plantings between December and January. Lower values of AUDPC occurred in later plantings at both locations. The epidemic rate was positively correlated (P < 0.05) with the mean daily temperatures and negatively correlated with hours of relative humidity >90%. The AUDPC was not correlated with any weather variable. The AUDPCi was negatively related to both variables connected to humidity, but not to rain. Long periods (mostly >13 h day-1) of relative humidity >90% (that corresponded to leaf wetness) occurred in Castro. Severity of southern rust in maize has always been low in Castro, thus the negative correlations between disease and the two humidity variables.
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Pscheidt, Jay W., and Stephanie Heckert. "Progression of Kernel Mold on Hazelnut." Plant Disease 105, no. 5 (May 1, 2021): 1320–27. http://dx.doi.org/10.1094/pdis-05-20-1088-re.
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Hazelnut kernel mold, caused by a number of fungal species, has been a chronic problem in Pacific Northwest hazelnut production areas for many years. Two highly susceptible breeding selections and two commercial cultivars were used to investigate kernel mold development over time and possible correlations with rainfall. Nuts were allowed to naturally fall onto orchard soil, regularly collected, cracked open, and evaluated for kernel mold. Disease progress for each selection or cultivar was evaluated each year with both linear and exponential models. The general progression of kernel mold was similar for the two breeding selections and cultivars Ennis and Lewis, where kernel mold increased slowly during the nut dropping period but more rapidly after normal harvest. An exponential model described disease progress better than a linear model for 8 of the 10 significant disease progress curves examined. Although some years had significantly higher estimated rates of disease increase, this parameter was inversely related to the area under the disease progress curve (AUDPC). The incidence of kernel mold did not significantly increase over time for 8 of the 18 disease progress curves examined, including 6 of 8 curves for commercial cultivars. The relationship between initial kernel mold incidence and AUDPC was described well with a simple linear model indicating that initial disease incidence appeared to be a good predictor of AUDPC. The longer nuts remained on the ground, especially after harvest, the higher the incidence of kernel mold. Kernel mold incidence was not significantly correlated with rainfall totals for any period of time from flowering to harvest. Multiple harvests ending shortly after all nuts have fallen should result in lower incidence of kernel mold for growers.
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Pereira, Renata C. M., Maria A. Ferreira, Thaissa P. F. Soares, Mario F. C. M. Andrade, Cézar A. L. Filho, Edson A. Pozza, Maria L. M. Avelar, and Lucas A. Melo. "Temporal Progress of Candeia Rust Caused by Puccinia velata in Clonal Candeia Plantation (Eremanthus erythropappus (DC.) McLeisch)." Forests 11, no. 7 (June 29, 2020): 720. http://dx.doi.org/10.3390/f11070720.
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The temporal progress of candeia rust, caused by the fungus Puccinia velata, was monitored in an experimental field at Lavras municipality, Southern Minas Gerais state, Brazil. A plantation with 17 Eremanthus erythropappus clones was set at the site, and the temporal disease progress was analyzed based on visual assessments of disease severity on leaves. The disease was monitored monthly between September 2016 and August 2017. Progress curves based on disease severity were constructed and empirical models were fitted. The area under the disease progress curve (AUDPC) was calculated, and the means test was applied to select clones resistant to the disease. The Pearson coefficient was used to assess correlations between disease severity and environmental variables. The model that best described disease progress over the assessment period was the Gompertz model. The mean AUDPC values were grouped into four groups of resistance levels according to the Scott–Knott test. There was a negative correlation between air temperature and disease severity. Considering that the disease occurred in all clones and that the climatic conditions of Southern Minas Gerais are favorable to the candeia rust, it is important to adopt measures for the selection of clones resistant to this disease.
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Park, E. W. "Empirical Estimation of the Asymptotes of Disease Progress Curves and the Use of the Richards Generalized Rate Parameters for Describing Disease Progress." Phytopathology 75, no. 7 (1985): 786. http://dx.doi.org/10.1094/phyto-75-786.
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Navas-Cortés, Juan A., Bernhard Hau, and Rafael M. Jiménez-Díaz. "Effect of Sowing Date, Host Cultivar, and Race of Fusarium oxysporum f. sp. ciceris on Development of Fusarium Wilt of Chickpea." Phytopathology® 88, no. 12 (December 1998): 1338–46. http://dx.doi.org/10.1094/phyto.1998.88.12.1338.
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Microplots experiments were carried out at Córdoba, southern Spain, from 1986 to 1989 to determine the effects of sowing date in the management of Fusarium wilt of chickpea as influenced by virulence of the pathogen race and by cultivar susceptibility. A total of 108 epidemics of the disease were described, analyzed, and compared to assess the degree of disease control. The epidemics were characterized by five curve elements: final disease intensity index (DII), standardized area under DII progress curve, time to epidemic onset, time to inflection point (tip), and the DII value at tip, the last two parameters being estimates from the Richards function adjusted by nonlinear regression analysis. The structure of Fusarium wilt epidemics was examined by conducting multivariate principal components and cluster analyses. From these analyses, three factors accounting for 98 to 99% of the total variance characterized the DII progress curves and provided plausible epidemiological interpretations. The first factor included the tip and the time to disease onset and can be interpreted as a positional factor over time. This factor accounted for the largest proportion of the total variance and may, therefore, be considered as the main factor for analysis of Fusarium wilt epidemics. The second factor concerns the standardized area under DII progress curves and the final DII of the epidemics. The third factor identified the uniqueness of the estimated value for the point of inflection of the DII progress curve over time. Our results indicate that for each year of experiment epidemic development was related mainly to the date of sowing. Thus, for chickpea crops in southern Spain, advancing the sowing date from early spring to early winter can slow down the development of Fusarium wilt epidemics, delay the epidemic onset, and minimize the final amount of disease. However, the net effect of this disease management practice may also be influenced, though to a lesser extent, by the susceptibility of the chickpea cultivar and the virulence and inoculum density of the Fusarium oxysporum f. sp. ciceris race.
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Nascimento, Jefferson Fernandes do, João Batista Vida, Dauri José Tessmann, Laércio Zambolim, Rafael Augusto Vieira, and Ricardo Ribeiro de Oliveira. "Progress of Asian soybean rust and airborne urediniospores of Phakopsora pachyrhizi in southern Brazil." Summa Phytopathologica 38, no. 4 (December 2012): 280–87. http://dx.doi.org/10.1590/s0100-54052012000400002.
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Asian soybean rust, caused by the fungus Phakopsora pachyrhizi, was reported at epidemic levels in 2003/2004 and is the main soybean disease in Brazil. The aim of this study was to investigate the spread of Asian soybean rust and to quantify airborne urediniospores in the region of Campo Mourão, Paraná State, Brazil. Three experiments were conducted under field conditions during the 2007/08 and 2008/09 crop seasons. Using the disease gradient method, provided by the application of increasing levels of the fungicide tebuconazole, four Asian soybean rust epidemics at different intensities were obtained in each experiment. To quantify the urediniospores, weathercock-type spore collectors were installed during and between the two crop seasons. Disease progress curves were plotted for each epidemic, and maximum severity was estimated. The curves were fit to the logistic model, which provided higher coefficients of determination and more randomly distributed residuals plotted over time. Analyses of the area under the disease progress curve showed that the largest epidemics occurred in the 2007/2008 crop season and that the progress rates were higher for severity, even among plants protected with the fungicide. The number of urediniospores collected in the air was related to the presence of soybean plants in the cultivated crops. The quantity of urediniospores was also positively correlated to the disease severity and incidence, as well as to cumulative rainfall and favorable days for P. Pachyrhizi infection.
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Reis, Erlei Melo, Cristina Boareto, Anderson Luiz Durante Danelli, and Sandra Maria Zoldan. "Anthesis, the infectious process and disease progress curves for fusarium head blight in wheat." Summa Phytopathologica 42, no. 2 (June 2016): 134–39. http://dx.doi.org/10.1590/0100-5405/2075.
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ABSTRACT Fusarium head blight of wheat (Triticum aestivum), caused by the fungus Gibberella zeae, is a floral infecting disease that causes quantitative and qualitative losses to winter cereals. In Brazil, the sanitary situation of wheat has led to research in order to develop strategies for sustainable production, even under adverse weather conditions. To increase the knowledge of the relationship among the presence of anthesis, the infectious process, the disease progress and the saprophytic fungi present in wheat anthers, studies were conducted in the experimental field of University of Passo Fundo (UPF), using the cultivar Marfim, in the 2011 growing season. The disease incidence in spikes and spikelets was evaluated. The presence of exserted anthers increased the spike exposure time to the inoculum. The final incidence of fusarium head blight, in the field, was dependent on the presence of exserted anthers. The disease followed an aggregation pattern and its evolution increased with time, apparently showing growth according to secondary cycles. The fungi isolated from exserted anthers (Alternaria sp., Fusarium sp., Drechslera spp. and Epicoccum sp.) did not compete for the infection site of fusarium head blight in wheat, not interfering with the incidence of F. graminearum.
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Skelsey, P., G. J. T. Kessel, W. A. H. Rossing, and W. van der Werf. "Parameterization and Evaluation of a Spatiotemporal Model of the Potato Late Blight Pathosystem." Phytopathology® 99, no. 3 (March 2009): 290–300. http://dx.doi.org/10.1094/phyto-99-3-0290.
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A spatiotemporal, integrodifference equation model of the potato late blight pathosystem is described. Formerly, the model was used in a theoretical context to analyze and predict epidemic dynamics in spatially heterogeneous mixtures of host genotypes. The model has now been modified to reflect a research interest in interactions between genotype, environment, landscape, and management. New parameter values describing host–pathogen interactions were determined and new environment–pathogen relationships included. A new analytical equation describing lesion expansion and associated necrosis has also been developed. These changes prompted a need to assess the quality of model predictions. Cultivar–isolate-specific interactions were characterized in the model using three quantitative components of resistance: infection efficiency, lesion growth rate, and sporulation intensity. These were measured on detached potato leaflets in the laboratory. Results of a sensitivity analysis illuminate the effect of different quantitative components of resistance and initial conditions on the shape of disease progress curves. Using the resistance components, the epidemic process of lesion expansion was separated from the epidemic process of lesion propagation providing two reference curves for diagnosing observed epidemics. The spatial component of the model was evaluated graphically in order to determine if realistic rates of focal expansion for potato late blight are produced. In accordance with theory, the radius of a predicted focus increased linearly with time and a constant focal velocity was reached that compared well with published experimental data. Validation data for the temporal model came from 20 late blight epidemics observed in field trials conducted in the Netherlands in 2002 and 2004. The field data and model were compared visually using disease progress curves, and numerically through a comparison of predicted and observed t5 and t50 points (time in days until 5 and 50% disease severity is reached, respectively) and relative areas under the disease progress curve values. Temporal model predictions were in close agreement with observational data and the ability of the model to translate measured resistance components, weather data, and initial conditions into realistic disease progress curves without the need for calibration confirms its utility as a tool in the analysis and diagnosis of epidemics.
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Holb, I. J., B. Heijne, J. C. M. Withagen, J. M. Gáll, and M. J. Jeger. "Analysis of Summer Epidemic Progress of Apple Scab at Different Apple Production Systems in the Netherlands and Hungary." Phytopathology® 95, no. 9 (September 2005): 1001–20. http://dx.doi.org/10.1094/phyto-95-1001.
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Two, 4-year studies on summer epidemic progress of apple scab were conducted at Randwijk, the Netherlands, from 1998 until 2001 and at Eperjeske, Hungary, from 2000 until 2003. Disease assessments were made on scab-susceptible cv. Jonagold. A range of nonlinear growth functions were fitted to a total of 96 disease progress curves (3 treatment classes × 2 plant parts × 2 disease measures × 4 years × 2 locations) of apple scab incidence and severity. The three-parameter logistic model gave the most consistent fit across three treatment classes in the experiment (integrated, organic-sprayed, and organic-unsprayed). Parameters estimated or calculated from the three-parameter logistic function were used to analyze disease progress. These were disease incidence and severity on the day of the first assessment (Ys); final disease incidence or upper asymptote for incidence (Yif) or severity (Ysf); fruit incidence and severity on day 40, after which no new lesions on fruits appeared (Y40); leaf incidence and severity on day 75, at which shoot growth stopped (Y 75); relative (β) and “absolute” (θ) rates of disease progress; inflection point (M); and area under the disease progress curve (AUDPCS) standardized by the duration of the total epidemic. Comparisons among disease progress curves were made by correlation and factor analysis followed by Varimax rotation. There were large differences but high positive correlations among the parameters Ys, Yf, θ, and AUDPCS across the three treatment classes. In the factor analysis, two factors accounted for more than 85% of the total variance for both incidence and severity. Factor 1 gave an overall description of epidemic progress of both scab incidence and severity and included the parameters Yf, Y40, Y75, θ, and AUDPCS. Factor 2 identified a relationship between the relative rate parameter (β) and the inflection point (M) for severity and a relationship between disease incidence and severity. For an integrated or an organic orchard, θ, AUDPCS, and one of Yf or Y75 (because of the link with host phenology) can characterize apple scab epidemics during summer. Based on these findings, improved scab management approaches were provided for integrated and organic apple production systems.
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WERKER, A. R., C. A. GILLIGAN, and D. HORNBY. "Analysis of disease-progress curves for take-all in consecutive crops of winter wheat." Plant Pathology 40, no. 1 (March 1991): 8–24. http://dx.doi.org/10.1111/j.1365-3059.1991.tb02288.x.
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MUKHERJEE, A. K., N. K. MOHAPATRA, A. V. SURIYA RAO, and P. NAYAK. "Effect of nitrogen fertilization on the expression of slow-blasting resistance in rice." Journal of Agricultural Science 143, no. 5 (September 30, 2005): 385–93. http://dx.doi.org/10.1017/s0021859605005551.
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The development of rice blast disease in four slow-blasting (SB) genotypes was compared with that in the fast-blasting (FB) genotype Karuna, under natural field epidemics over a period of 3 years at five levels of nitrogen, in order to determine if the application of high doses of nitrogen influenced the expression of disease progress in the SB types. The treatment effects were compared through estimation of nine parameters viz. (i) lesion number (LN); (ii) area under disease progress curve (AUDPC); (iii) relative area under disease progress curve (RAUDPC); (iv) logistic apparent infection rate (r); (v) Gompertz apparent infection rate (k); (vi) logit line intercept (logit-a); (vii) gompit line intercept (gompit-a); (viii) time required for the disease to reach 0·25 severity in logistic (T25r); and (ix) Gompertz (T25k) models. There was a significant increase in LN, AUDPC, RAUDPC, r and k with increased levels of nitrogen application in all genotypes, but the rate of increase in disease severity was much lower in SB genotypes than the FB one and did not lead to breakdown of resistance in the SB genotypes, since severity level was much below the economic injury level. Among the nine derived parameters for evaluation of resistance LN, AUDPC, RAUDPC, r and k were best. The AUDPC and RAUDPC had lower degrees of error variance compared with the other parameters and hence were considered superior measures for characterization of disease progress curves.
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Fravel, D. R., P. B. Adams, and W. E. Potts. "Use of disease progress curves to study the effects of the biocontrol agentSporidesmium sclerotivorumon lettuce drop." Biocontrol Science and Technology 2, no. 4 (January 1992): 341–48. http://dx.doi.org/10.1080/09583159209355250.
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de Oliveira, Mara Elisa Soares, Fabiano Silva Fernandes, Murilo A. Glória Junior, Alvaro Soares de Oliveira, Reginaldo Gonçalves Mafia, and Maria Alves Ferreira. "Temporal Analysis of Bacterial Leaf Blight in Clonal Eucalyptus Plantations in Brazil." Forests 10, no. 10 (September 25, 2019): 839. http://dx.doi.org/10.3390/f10100839.
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Bacterial leaf blight is an important disease in Eucalyptus spp. plantations since it can cause defoliation, affecting plant development. A better understanding of the disease epidemiology is important for its control. Thus, the aim of this study was to analyze bacterial leaf blight temporal progress in the initial establishment in the field of different eucalyptus clones. It also targeted to correlate the incidence and area under the disease-progress curve (AUDPC), with variables related to growth and meteorological data. Bacterial leaf blight progress curves were analyzed based on incidence and carried out AUDPC calculation. Pearson’s coefficient was used to verify the correlations between bacterial leaf blight incidence and AUDPC with clone initial growth and meteorological factors. Gompertz or Logistic models were the best adjustment to data, according to the assessed clones. A difference in AUDPC was observed between clones regarding bacterial leaf blight incidence during the assessment period. Clones were divided into three groups with different tolerance levels. A negative correlation was observed between bacterial leaf blight incidence, AUDPC, and growth variables of clones. During the assessment period, average air temperature, rainfall, and air relative humidity favored disease incidence. The clones A469, VM01, and 373 were the most tolerant to the disease.
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Rempel, Curtis B., and Robert Hall. "Comparison of disease measures for assessing resistance in canola (Brassica napus) to blackleg (Leptosphaeria maculans)." Canadian Journal of Botany 74, no. 12 (December 1, 1996): 1930–36. http://dx.doi.org/10.1139/b96-230.
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Disease incidence, disease severity, areas under the disease incidence and disease severity progress curves, and maximum and minimum incidence and severity of disease were evaluated as measures of resistance in canola (Brassica napus) to blackleg caused by Leptosphaeria maculans. Seven genotypes of spring canola were tested in Ontario at three locations 60, 81, and 102 days after sowing in 1990 and at two locations 55, 70, 85, and 100 days after sowing in 1991. Disease incidence was expressed as the percentage of sampled plants with basal stem canker, and disease severity was assessed as the percentage discolouration of a cross section of the stem base. Based on ease of measurement, range of values, number of significant differences among genotypes, and constancy of rank of genotypes at different locations, measures of disease severity or disease incidence in mature plants proved to be most useful. No advantage was gained by using area under the disease incidence and disease severity progress curves, or maximum and minimum incidence and severity of disease at the last sampling time. It is recommended that resistance of canola stems to blackleg be evaluated from measures of disease severity or disease incidence in mature plants. Keywords: canola, blackleg, Leptosphaeria maculans, resistance measurements.
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Soto-Estrada, Alejandra, and James E. Adaskaveg. "Temporal and Quantitative Analyses of Stem Lesion Development and Foliar Disease Progression of Peach Rust in California." Phytopathology® 94, no. 1 (January 2004): 52–60. http://dx.doi.org/10.1094/phyto.2004.94.1.52.
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The development of rust epidemics caused by Tranzschelia discolor on leaves and stems of cling peach was studied in California orchards. Sporulating stems lesions were only detected from late March until July in 1997 and 1998. When rust was present in the fall, the quadratic equation Y = -82.51 + 1.97JD - 0.01JD2 using Julian day (JD) described the incidence of sporulating lesions on stems of cv. Andross (R2 = 0.73; P ≤ 0.001) in the following spring season. Late-season rust epidemics occurred in 1996 and 1997. Incidence of rust on leaves of cvs. Andross and Ross was <10% from April through July and 80 to 100% by October/November. In 1998, early-season epidemics developed with disease incidence at 28 to 56% by July/August in two cv. Andross orchards. No disease was observed during the 1999 growing season. Using linear regression analysis, logistic and exponential models best described the development of disease in 1996 and 1997, respectively. In contrast, the monomolecular model best described the disease in 1998. In an analysis of variance comparing disease progress curves on cv. Andross from 1996 to 1998, no significant differences in area under the disease progress curve and ρ were observed, whereas ymax was significantly different (P < 0.001). A repeated measures analysis indicated that in a cv. Andross orchard the year of the disease progress curve, time of sampling, and their interaction were highly significant (P < 0.01). This indicated a distinct difference between early- and late-season epidemics. Earlyseason development of rust on leaves occurred in years with ≥117.3 mm of total precipitation and maximum temperatures of ≤30.2°C in April to June.
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Culbreath, A. K., J. W. Todd, D. W. Gorbet, and J. W. Demski. "Spotted Wilt Apparent Disease Progress in the Component Lines of Southern Runner Cultivar." Peanut Science 20, no. 2 (July 1, 1993): 81–84. http://dx.doi.org/10.3146/i0095-3679-20-2-4.
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Abstract The apparent disease progress of spotted wilt, caused by tomato spotted wilt virus, was monitored in the three component lines of Southern Runner peanut (Arachis hypogaea L.), and in cultivars Southern Runner, Florunner and GK-7 in the field in 1990-1992. In all three years, final incidence and area under the disease progress curves were similar among Southern Runner and all three component lines. Final incidence of spotted wilt in Southern Runner and all component lines was less than for Florunner in all three years. AUDPC values were lower in Southern Runner and two of the three component lines than in Florunner. Incidence and AUDPC of spotted wilt in GK-7 was intermediate between Florunner and Southern Runner and its individual components. Disease increase was linear in all component lines and cultivars. Rate of disease progress was similar among Southern Runner and the three component lines. Disease progressed more slowly in Southern Runner and the component lines than in Florunner.
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Shearer, B. L., C. E. Crane, S. Barrett, and A. Cochrane. "Assessment of threatened flora susceptibility toPhytophthora cinnamomiby analysis of disease progress curves in shadehouse and natural environments." Australasian Plant Pathology 36, no. 6 (2007): 609. http://dx.doi.org/10.1071/ap07074.
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Mukherjee, Arup Kumar, Nalini Kanta Mohapatra, and Parsuram Nayak. "Estimation of area under the disease progress curves in a rice-blast pathosystem from two data points." European Journal of Plant Pathology 127, no. 1 (December 18, 2009): 33–39. http://dx.doi.org/10.1007/s10658-009-9568-2.
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Pohanka, Miroslav, Oto Pavliš, Jiří Pikula, František Treml, and Kamil Kuca. "Modulation of Tularemia Disease Progress by the Bisquaternary Pyridinium Oxime HI-6." Acta Veterinaria Brno 79, no. 3 (2010): 443–48. http://dx.doi.org/10.2754/avb201079030443.
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Cholinesterase reactivator HI-6 is a drug commonly used to treat individuals exposed to nerve agents. Recent experiments proved HI-6 impact on parasympathetic response and impact on the nervus vagus associated cholinergic anti-inflammatory pathway is hypothesized here. The modulation effect of HI-6 was studied on BALB/c mice infected with Francisella tularensis, the bacteria causing tularemia. Cultivation test in vitro confirmed weak bacteriostatic effects of HI-6. Results in experiments revealed intriguing effect differences resulting from HI-6 administration to mice. While the HI-6 dose of 7 mg per animal (pro toto) had no significant effects on infection progress, lower dose of 8 μg of HI-6 pro toto reduced mice mortality caused by tularemia infection compared to control group of mice infected only with F. tularensis (survival curves were compared by the logrank test, chi square = 4.335, df = 1, P = 0.0373). The effect observed in mice exceeded the effect provided in vitro on bacterial cultures. Though the exact molecular mechanism of HI-6 modulation during infection should be investigated, HI-6 is seems to be suitable as immunomodulans.
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SALES, Nathana Izabela Silva, Evelynne Urzêdo LEÃO, Lucas Caius Moreira do Amaral CORREIA, Chrystian de Assis SIQUEIRA, and Gil Rodrigues dos SANTOS. "Temporal progress of teak rust in a tropical area of Tocantins State, Brazil." Acta Amazonica 47, no. 3 (July 2017): 277–80. http://dx.doi.org/10.1590/1809-4392201603212.
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ABSTRACT Rust, caused by Olivea neotectonae, stands out as the main teak disease, causing premature defoliation regardless of the tree’s growth stage. In this study, we aimed to assess the temporal progress of rust in adult teak plants in southern Tocantins State (Brazil). Both rust incidence and severity were evaluated and the disease progress curves were obtained, adjusting to monomolecular, logistic and Gompertz mathematical models. Data from incidence and severity were correlated with climate variables collected by the agrometeorological station located in the study area. Rust incidence reached 100% at 98 days after beginning of the evaluations (DBE). The highest severity (equal or above 75%) was observed at 147 DBE. There was a significant and negative correlation between severity and minimum temperature. The adjustment of the Gompertz model suggests that control measures should be aimed primarily to reduce the rate of disease progress.
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Bailey, D. J., and C. A. Gilligan. "Dynamics of Primary and Secondary Infection in Take-All Epidemics." Phytopathology® 89, no. 1 (January 1999): 84–91. http://dx.doi.org/10.1094/phyto.1999.89.1.84.
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Using a combination of experimentation and mathematical modeling, the effects of initial (particulate) inoculum density on the dynamics of disease resulting from primary and secondary infection of wheat by the take-all fungus, Gaeumannomyces graminis var. tritici, were tested. A relatively high inoculum density generated a disease progress curve that rose monotonically toward an asymptote. Reducing the initial inoculum density resulted in a curve that initially was monotonic, rising to a plateau, but which increased sigmoidally to an asymptotic level of disease thereafter. Changes in the infectivity of particulate inoculum over time were examined in a separate experiment. Using a model that incorporated terms for primary and secondary infection, inoculum decay, and host growth, we showed that both disease progress curves were consistent with consecutive phases dominated, respectively, by primary and secondary infection. We examined the spread of disease from a low particulate inoculum density on seminal and adventitious root systems separately. Although seminal roots were affected by consecutive phases of primary and secondary infection, adventitious roots were affected only by secondary infection. We showed that the characteristic features of disease progress in controlled experiments were consistent with field data from crops of winter wheat. We concluded that there is an initial phase of primary infection by G. graminis var. tritici on winter wheat as seminal roots grow through the soil and encounter inoculum, but the rate of primary infection slows progressively as inoculum decays. After the initial phase, there is an acceleration in the rate of secondary infection on both seminal and adventitious roots that is stimulated by the increase in the availability of infected tissue as a source of inoculum and the availability of susceptible tissue for infection.
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Dillard, H. R., and A. C. Cobb. "Disease Progress of Black Dot on Tomato Roots and Reduction in Incidence with Foliar Applied Fungicides." Plant Disease 81, no. 12 (December 1997): 1439–42. http://dx.doi.org/10.1094/pdis.1997.81.12.1439.
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Progression of black dot caused by Colletotrichum coccodes was determined at regular intervals on roots of processing tomatoes growing in a naturally infested field. In 1993 and 1994, C. coccodes was first isolated from tomato roots 30 and 37 days after transplanting, respectively, which corresponded to the opening of flowers in the first flower clusters. Black dot incidence increased rapidly from the time when large green fruit were present to production of mature red fruit. In both years, C. coccodes was isolated from the roots of 97% of the plants at the postharvest sampling date (162 days after transplanting). Areas under the incidence disease progress curves were not significantly different in the 2 years of study (1993 = 83.5, 1994 = 86.9). Root decay was severe at the postharvest sampling, and sclerotia of C. coccodes were abundant on the roots. C. coccodes was isolated from 38 and 44% of the root segments in 1993 and 1994, respectively. Areas under the disease progress curves for infected root segments were not significantly different in the 2 years of study (1993 = 25.8, 1994 = 33.9). In a separate study, chlorothalonil (2.5 kg/ha) or mancozeb (1.68 kg/ha) was applied at 7-, 10-, or 14-day intervals to tomato plants. Recovery of C. coccodes from root segments at harvest (113 to 118 days after transplanting) was significantly reduced in the chlorothalonil 7- or 10-day and mancozeb 10-day interval treatments in both years. However, the percentage of plants with black dot was not consistently reduced by fungicide applications.
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López-Escudero, F. J., and M. A. Blanco-López. "Relationship Between the Inoculum Density of Verticillium dahliae and the Progress of Verticillium Wilt of Olive." Plant Disease 91, no. 11 (November 2007): 1372–78. http://dx.doi.org/10.1094/pdis-91-11-1372.
Full textAbstract:
An experiment was conducted in microplots which were artificially infested with a defoliating isolate of Verticillium dahliae using seven different treatments of inoculum densities ranging from 0 to 10 microsclerotia per gram of soil (ppg). The experiment was conducted in Andalucía (southern Spain), and the susceptible Spanish olive cv. Picual was used to determine the relationship between pathogen inoculum density and the progress of Verticillium wilt of olive (VWO). The inoculum, produced on a sodium pectate cellophane medium, was found to efficiently infect olive trees. Symptoms first appeared 30 weeks after the trees were transplanted into infested soil. Periods of increasing disease incidence in the following seasons and years were mainly during spring and autumn, particularly in the second year after planting. Olive trees exhibited a high susceptibility to the defoliating pathotype of the pathogen, even at very low inoculum levels; in fact, diseased plants were encountered throughout the experiment regardless of the inoculum density treatment. Inoculum densities greater than 3 ppg in the soil resulted in final disease incidence greater than 50% for the trees after 2.5 years. Therefore, these inoculum densities must be considered very high for olive trees. There were no differences in final disease incidence, mean symptom severity, or area under the disease progress curve between plots infested with 10 or 3.33 ppg, whereas other treatments exhibited lower values for each of these disease parameters. The temporal variations of disease incidence and severity were highly correlated for the higher inoculum density treatments, with r2 values ranging from 0.92 to 0.84 for disease incidence and from 0.93 to 0.88 for severity. However, r2 was slightly lower for the treatments involving lower inoculum densities of the pathogen in microplots. The slopes of the linear regression curves were statistically different for nearly all the inoculum density treatments. Positive correlation was found between the initial inoculum density and final disease incidence values after the study period that was accurately explained by mathematical models. The results suggest that susceptible olive cultivars should not be planted in soils infested with virulent defoliating pathotypes of V. dahliae. Results also clarify that inoculum density levels obtained from field soil analyses can be used for establishing a risk prediction system with a view to controlling VWO in olive tree plantations.
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Nemesia C. San Juan, Bachiller, and Reynaldo G. Abad. "Distribution and progression of stem bleeding disease of coconut (Cocos nucifera L.) in some areas of the Philippines." CORD 20, no. 02 (December 1, 2004): 34. http://dx.doi.org/10.37833/cord.v20i02.386.
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Records of disease occurrence in surveyed provinces show Davao del Sur having the highest disease incidence of stem bleeding caused by Thielaviopsis paradoxa (de Seynes) von Hohnel. Disease incidence in Malayan Yellow Dwarf x West African Tall (MYD x WAT) hybrid at the PCA’s Zamboanga Research Center was relatively lower than the other areas observed. Tall genotypes are less susceptible to the disease as shown in the province of Quezon where the cultivar Laguna Tall is predominantly grown. The incidence of stem bleeding was found to be related with palms age. More incidence of the disease was noted in palms between 11-15 years old.
Study on the spatial distribution of the disease from l991 to l995 show that the disease initially occurred in random foci, and, subsequently infected adjacent palms.
The disease progress curves suggest that stem bleeding follows a sigmoid curve. It follows that the progress of the disease at any given time is a function of the initial inoculums and the number of effective contact points between susceptible host and inoculums per unit time. Analysis of the infection rates using logistic growth model showed that the rate of disease increase ranged from 0.029 to 0.218 per unit per year and 0.227 per unit per year in all the six experimental areas.
Increase in disease incidence is directly related to high amount of rainfall.
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Turechek, William W., Pamela D. Roberts, Philip A. Stansly, Craig G. Webster, Chandrasekar S. Kousik, and Scott Adkins. "Spatial and Temporal Analysis of Squash vein yellowing virus Infections in Watermelon." Plant Disease 98, no. 12 (December 2014): 1671–80. http://dx.doi.org/10.1094/pdis-10-13-1094-re.
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Squash vein yellowing virus (SqVYV) is a whitefly-transmitted ipomovirus infecting watermelon and other cucurbits that was recently introduced to Florida. Effects on watermelon are devastating, with total vine collapse, often near harvest, and fruit rendered unmarketable by brown, discolored flesh. The epidemiology of SqVYV was studied in a 1-ha field of ‘Fiesta’ watermelon over six growing seasons (I to VI) to characterize the spatial patterning of disease and temporal rate of disease progress, as well as its association with Cucurbit leaf crumple virus (CuLCrV) and Cucurbit yellow stunting disorder virus (CYSDV), two additional whitefly-transmitted viruses that often occur with SqVYV. The field was scouted at regular intervals for the length of the season for incidence of virus and number of whiteflies. Incidence of SqVYV reached 100% during seasons I, II, and V and 20% during season III. SqVYV did not occur during seasons IV and VI. SqVYV progressed in a characteristic logistic fashion in seasons I, II, and V but less so in season III. The rate of disease progress was similar for the three seasons with high disease incidence, with an average value of 0.18. A positive correlation between the area under the disease progress curve and whitefly-days was found, where both progress curves were calculated as a function of thermal time (degree days, base 0°C). SqVYV displayed significant but variable levels of aggregation, as indicated by its fit to the β-binomial distribution, the binary power law, and ordinary runs analysis. Association analysis indicated that the viruses were largely transmitted independently. Results of this study provide epidemiological information that will be useful in the development of management strategies for SqVYV-induced vine decline, and provide new information for CuLCrV and CYSDV.
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Andrivon, D., R. Pellé, and D. Ellissèche. "Assessing resistance types and levels to epidemic diseases from the analysis of disease progress curves: Principles and application to potato late blight." American Journal of Potato Research 83, no. 6 (November 2006): 455–61. http://dx.doi.org/10.1007/bf02883506.
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Rowe, Jacob M., and Anthony H. Goldstone. "How I treat acute lymphocytic leukemia in adults." Blood 110, no. 7 (October 1, 2007): 2268–75. http://dx.doi.org/10.1182/blood-2007-05-038950.
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The treatment of newly diagnosed acute lymphocytic leukemia (ALL) in adults remains unsatisfactory. Not withstanding the outstanding progress in curing childhood ALL, only approximately one third of adults younger than 60 years can be cured, and the overall published survival curves have not changed significantly during the past 15 years. Recent therapeutic advances in allogeneic transplantation through the conduct of large collaborative studies, better understanding of the relevance of cytogenetics, improved molecular techniques for the detection of minimal residual disease, and clinical research into novel biologic and targeted therapies have all combined to offer potentially a better hope for an improved outcome in this disease. The current approach in 2007 to the management of this disease is presented by way of a discussion of illustrative cases. In this uncommon and difficult disease, well-structured intergroup studies will remain vital for future progress.
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Li, Yonghao, and David O. TeBeest. "Temporal and Spatial Development of Sorghum Anthracnose in Arkansas." Plant Disease 93, no. 3 (March 2009): 287–92. http://dx.doi.org/10.1094/pdis-93-3-0287.
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Development of sorghum anthracnose in time and space on susceptible (‘BTx623’ and ‘Pioneer 8313’) and resistant (‘Cargill 888Y’) sorghum (Sorghum bicolor) cultivars was investigated in field plots inoculated with a mixture of three strains (T430-SW, Ar54-SW, and ArSS-1SW) of Colletotrichum sublineolum in 2001 and 2002. After slow development during early growth stages, sorghum anthracnose developed rapidly after flowering. The logistic model provided a good statistical fit for disease progress curves for sorghum anthracnose in Arkansas. Compared to susceptible cultivars, the resistant cultivar had significantly lower values for the standard area under the disease progress curve, a lower upper asymptote, and delayed epidemic onset. However, there were no significant differences in infection rate and the time of the inflection points, the times at which the disease proportion equaled values of one-half of upper asymptotes, among the three cultivars. The negative exponential model more closely described disease gradients of sorghum anthracnose than the inverse power law model. There were significant differences in intercepts but not in slopes and half-distance between the resistant and susceptible cultivars. The slopes of disease gradients were significantly lower at 78 days after inoculation (DAI) than at 57 DAI on the three cultivars. The results could provide epidemiological components of sorghum anthracnose to help evaluate sorghum cultivars and breeding lines under field conditions.
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Huang, Y. H., and G. L. Hartman. "Reaction of Selected Soybean Genotypes to Isolates of Fusarium solani f. sp. glycines and Their Culture Filtrates." Plant Disease 82, no. 9 (September 1998): 999–1002. http://dx.doi.org/10.1094/pdis.1998.82.9.999.
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Four soybean plant introductions, PI 520.733, PI 567.374, PI 567.650B, and PI 567.659, and one soybean cultivar, Great Lakes 3202, were inoculated under greenhouse conditions with four isolates of Fusarium solani f. sp. glycines. Foliar disease severity rating was greatest on PI 567.659, followed by Great Lakes 3202, PI 520.733, PI 567.650B, and PI 567.374. There was no significant interaction between isolates and soybean entries for foliar disease severity ratings. Experiments also were conducted to determine if disease development and root colonization differed among entries. Root infection of the five entries did not differ (P = 0.05). Foliar disease progress curves increased faster for PI 567.659 and Great Lakes 3202 than for PI 567.374. The area under the disease progress curve (AUDPC) value for PI 567.374 was the lowest and differed (P = 0.01) from AUDPC values for Great Lakes 3202 and PI 567.659. There were no differences (P = 0.01) in length of taproot lesions, losses in root dry weight, and vascular stem length discoloration among the entries, and there was no correlation (P = 0.05) between these measurements and foliar AUDPC values. Cut seedling stems immersed in culture filtrate developed interveinal chlorosis on leaves of each entry within 2 days. Disease severity on cut seedlings of PI 567.374 was lower (P = 0.01) than on the other entries. There was a positive correlation (r = 0.94, P = 0.05) between AUDPC values of the five entries inoculated with the fungus and the cut seedling test using culture filtrate.
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Copes, Warren E., and Harald Scherm. "Rhizoctonia Web Blight Development on Container-Grown Azalea in Relation to Time and Environmental Factors." Plant Disease 94, no. 7 (July 2010): 891–97. http://dx.doi.org/10.1094/pdis-94-7-0891.
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Rhizoctonia web blight, caused by binucleate Rhizoctonia spp., is an annual problem in the southern United States on container-grown azaleas (Rhododendron spp.) that receive daily irrigation. Disease progress was assessed weekly from mid-May to mid-September on nursery-grown plants at three locations in Mississippi and Alabama in 2006, 2007, and 2008. Disease onset, defined as the appearance of blighted leaves at the exterior canopy of at least one plant, occurred on average on 20 July, and calendar date was a more precise predictor of disease onset than several combined time–weather variables. Disease progress curves exhibited weekly fluctuations around a typically exponential increase in the mean number of symptomatic leaves per plant until early to mid-September, after which web blight severity leveled off or declined due to disease-induced leaf dehiscence and the appearance of new, asymptomatic leaves. Based on the relative increase in the log-transformed number of infected leaves per plant, weekly assessment periods were classified as having slow (≤0%), intermediate (>0 to <10%), or rapid (≥10% increase) disease progress. Three-day moving averages (MA) of various weather variables were calculated, and lagged values (by 5 days) of the MA were used in an attempt to predict disease progress as slow, intermediate, or rapid. Of the periods assessed as having slow disease progress in the 2006–2007 data set (model development data), 90.6% (29 of 32) met at least one of the following heuristically derived criteria for the lagged MA: min. temperature < 20.0°C, max. temperature > 35.0°C, avg. vapor pressure deficit < 2.50 hPa, or day of the year > 240 (28 August). One or more of these same criteria were met in 5 of 16 (31.2%) assessment periods with rapid disease progress, indicating that periods with slow versus rapid disease progression could be distinguished reasonably well based on weather. Results were similar for the 2008 validation data. However, weather variables were not useful in separating periods with either slow or rapid disease progress from those having intermediate progress. Instead, weather variables were most useful when used in a negative-prognosis approach to predict disease progression as being “not rapid” (which includes slow and intermediate periods) or “not slow” (including intermediate and rapid periods). The data set was further analyzed using Classification and Regression Tree (CART) analysis to relate weekly disease progress periods to weather variables. The resulting CART model agreed with the heuristic approach in that temperature variables were more prominent than moisture variables in classifying disease progress periods. With both approaches, satisfactory accuracy was accomplished only with negative-prognoses that classified disease progress periods as not rapid or not slow based on temperature and moisture limits.
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Hundemer, Gregory L., Navdeep Tangri, Manish M. Sood, Tim Ramsay, Ann Bugeja, Pierre A. Brown, Edward G. Clark, Mohan Biyani, Christine A. White, and Ayub Akbari. "Performance of the Kidney Failure Risk Equation by Disease Etiology in Advanced CKD." Clinical Journal of the American Society of Nephrology 15, no. 10 (September 14, 2020): 1424–32. http://dx.doi.org/10.2215/cjn.03940320.
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Background and objectivesThe kidney failure risk equation is a clinical tool commonly used for prediction of progression from CKD to kidney failure. The kidney failure risk equation’s accuracy in advanced CKD and whether this varies by CKD etiology remains unknown. This study examined the kidney failure risk equation’s discrimination and calibration at 2 and 5 years among a large tertiary care population with advanced CKD from heterogeneous etiologies.Design, setting, participants, & measurementsThis retrospective cohort study included 1293 patients with advanced CKD (median eGFR 15 ml/min per 1.73 m2) referred to the Ottawa Hospital Multi-Care Kidney Clinic between 2010 and 2016, with follow-up clinical data available through 2018. Four-variable kidney failure risk equation scores for 2- and 5-year risks of progression to kidney failure (defined as dialysis or kidney transplantation) were calculated upon initial referral and correlated with the subsequent observed kidney failure incidence within these time frames. Receiver operating characteristic curves and calibration plots were used to measure the discrimination and calibration of the kidney failure risk equation both in the overall advanced CKD population and by CKD etiology: diabetic kidney disease, hypertensive nephrosclerosis, GN, polycystic kidney disease, and other. Pairwise comparisons of the receiver operating characteristic curves by CKD etiology were performed to compare kidney failure risk equation discrimination.ResultsThe kidney failure risk equation provided adequate to excellent discrimination in identifying patients with CKD likely to progress to kidney failure at the 2- and 5-year time points both overall (2-year area under the curve, 0.83; 95% confidence interval, 0.81 to 0.85; 5-year area under the curve, 0.81; 95% confidence interval, 0.77 to 0.84) and across CKD etiologies. The kidney failure risk equation displayed adequate calibration at the 2- and 5-year time points both overall and across CKD etiologies (Hosmer–Lemeshow P≥0.05); however, the predicted risks of kidney failure were higher than the observed risks across CKD etiologies with the exception of polycystic kidney disease.ConclusionsThe kidney failure risk equation provides adequate discrimination and calibration in advanced CKD and across CKD etiologies.
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Fernández-Campos, M., C. Góngora-Canul, S. Das, M. R. Kabir, B. Valent, and C. D. Cruz. "Epidemiological Criteria to Support Breeding Tactics Against the Emerging, High-Consequence Wheat Blast Disease." Plant Disease 104, no. 8 (August 2020): 2252–61. http://dx.doi.org/10.1094/pdis-12-19-2672-re.
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Plant disease epidemiology can make a significant contribution for cultivar selection by elucidating the principles of an epidemic under different levels of resistance. For emerging diseases as wheat blast (WB), epidemiological parameters can provide support for better selection of genetic resources. Field experiments were conducted at two locations in Bolivia in 2018–2019 to characterize the temporal dynamics of the disease on 10 cultivars with different levels of reaction to WB. Logistic models best (R2 = 0.70–0.96) fit the disease progress curve in all cultivars followed by Gompertz (R2 = 0.64–0.94), providing additional evidence of a polycyclic disease. Total area under disease progress curve (tAUDPC), final disease severity (Ymax), and logistic apparent infection rates (rL*) were shown to be appropriate epidemiological parameters for describing resistance and cultivar selection. Cultivars that showed a high spike AUDPC (sAUDPC) showed a high leaf AUDPC (lAUDPC). tAUPDC, Ymax, and rL* were positively correlated among them (P < 0.01) and all were negatively correlated with grain weight (P < 0.01). Based on the epidemiological parameters used, cultivars that showed resistance to WB were Urubó, San Pablo, and AN-120, which were previously reported to have effective resistance against the disease under field conditions. The information generated could help breeding programs to make technical decisions about relevant epidemiological parameters to consider prior to cultivar release.
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Simko, Ivan, and Hans-Peter Piepho. "The Area Under the Disease Progress Stairs: Calculation, Advantage, and Application." Phytopathology® 102, no. 4 (April 2012): 381–89. http://dx.doi.org/10.1094/phyto-07-11-0216.
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The area under the disease progress curve (AUDPC) is frequently used to combine multiple observations of disease progress into a single value. However, our analysis shows that this approach severely underestimates the effect of the first and last observation. To get a better estimate of disease progress, we have developed a new formula termed the area under the disease progress stairs (AUDPS). The AUDPS approach improves the estimation of disease progress by giving a weight closer to optimal to the first and last observations. Analysis of real data indicates that AUDPS outperforms AUDPC in most of the tested trials and may be less precise than AUDPC only when assessments in the first or last observations have a comparatively large variance. We propose using AUDPS and its standardized (sAUDPS) and relative (rAUDPS) forms when combining multiple observations from disease progress experiments into a single value.
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Kuang, Liqun, Deyu Zhao, Jiacheng Xing, Zhongyu Chen, Fengguang Xiong, and Xie Han. "Metabolic Brain Network Analysis of FDG-PET in Alzheimer’s Disease Using Kernel-Based Persistent Features." Molecules 24, no. 12 (June 21, 2019): 2301. http://dx.doi.org/10.3390/molecules24122301.
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Recent research of persistent homology in algebraic topology has shown that the altered network organization of human brain provides a promising indicator of many neuropsychiatric disorders and neurodegenerative diseases. However, the current slope-based approach may not accurately characterize changes of persistent features over graph filtration because such curves are not strictly linear. Moreover, our previous integrated persistent feature (IPF) works well on an rs-fMRI cohort while it has not yet been studied on metabolic brain networks. To address these issues, we propose a novel univariate network measurement, kernel-based IPF (KBI), based on the prior IPF, to quantify the difference between IPF curves. In our experiments, we apply the KBI index to study fluorodeoxyglucose positron emission tomography (FDG-PET) imaging data from 140 subjects with Alzheimer’s disease (AD), 280 subjects with mild cognitive impairment (MCI), and 280 healthy normal controls (NC). The results show the disruption of network integration in the progress of AD. Compared to previous persistent homology-based measures, as well as other standard graph-based measures that characterize small-world organization and modular structure, our proposed network index KBI possesses more significant group difference and better classification performance, suggesting that it may be used as an effective preclinical AD imaging biomarker.
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Culbreath, A. K., W. D. Branch, J. P. Beasley, R. S. Tubbs, and C. C. Holbrook. "Peanut Genotype and Seeding Rate Effects on Spotted Wilt." Plant Health Progress 13, no. 1 (January 2012): 23. http://dx.doi.org/10.1094/php-2012-0227-03-rs.
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Establishing high plant populations helps suppress epidemics of spotted wilt, caused by Tomato spotted wilt virus (TSWV), in peanut (Arachis hypogaea L.). However, seed costs make it desirable to minimize seeding rates used. To determine whether new resistant genotypes can allow use of reduced seeding rates, field experiments were conducted at Tifton, GA, in 2008-2009 in which seven genotypes were combined factorially with two seeding rates, 9.8 and 19.7 seed/m of row. Genotypes included three cultivars (Georgia Green, Georgia-01R, and Georgia-02C) and four advanced breeding lines (GA 052524, GA 052527, GA 052529, and C724-19-25). Across years and genotypes, final incidences of spotted wilt and standardized areas under the spotted wilt disease progress curves were lower, and yields were higher in all other cultivars and breeding lines than in the moderately TSWV-resistant cultivar Georgia Green. Final incidence of spotted wilt was lower in GA 052527 and GA 052529 than in any of the cultivar standards, and yields of all four breeding lines were higher than for any of the three cultivars. Across genotypes, final incidence of spotted wilt and standardized areas under the spotted wilt disease progress curves were lower and yield was higher for the 19.8 seed/m treatment than the 9.8 seed/m. Accepted for publication 30 November 2011. Published 27 February 2012.
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Kalnins, Strele, and Lejnieks. "Comparison among Different Scoring Systems in Predicting Procedural Success and Long-Term Outcomes after Percutaneous Coronary Intervention in Patients with Chronic Total Coronary Artery Occlusions." Medicina 55, no. 8 (August 16, 2019): 494. http://dx.doi.org/10.3390/medicina55080494.
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Background and objectives: Different scoring systems are used to stratify patients with chronic total coronary artery occlusions (CTO) according to disease complexity to predict the success of the percutaneous coronary intervention (PCI). Comparison among different CTO scoring systems and long-term outcome for patients with CTO after PCI has not been well established. The objectives of the study were to assess the ability of different disease severity scoring systems to predict, first, procedural success and, second, overall survival in patients with a successful procedure. Materials and Methods: A total of 551 patients who underwent elective CTO PCI in Riga East University hospital from January 2007 to December 2016 were included in the study. Four scoring systems (J CTO, PROGRESS CTO, CL, and CASTLE) were calculated. ROC curves were used to assess the association between scores and procedural success, and the Kaplan–Meier method and Cox regression were used to estimate the association with death from any cause after a successful procedure, Results: 454 of 551cases were successful. With increasing disease complexity, the procedural success rate was significantly reduced in all scoring systems (p < 0.001): Area under the curve was 0.714 for J CTO score, 0.605 for PROGRESS CTO, 0.624 for CL and 0.641 for CASTLE scores. During the median 6.8 years of follow-up time, survival was better in the successful procedure group (p = 0.041). Among patients with procedural success, only PROGRESS and CASTLE scores showed an association with all-cause risk of death. After adjustment for baseline characteristics, patients having high PROGRESS score had almost twice higher risk of death (HR 1.81(95% CI 1.19–2.75)), and those with high and intermediate CASTLE score experienced almost four (HR 3.68(95% CI 1.50–9.05)) and two (HR 2.15, (95% CI 1.42–3.23)) times higher risk of death than the low score patients, respectively. Conclusions: All four CTO scoring systems had moderate ability to predict procedural success. More complex CTO PCI patients, assessed by PROGRESS and CASTLE scores, has worse all-cause survival in six to seven years after a successful procedure; whereas J CTO and CL scores had no association with survival.
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Madden, L. V., G. Hughes, and M. E. Irwin. "Coupling Disease-Progress-Curve and Time-of-Infection Functions for Predicting Yield Loss of Crops." Phytopathology® 90, no. 8 (August 2000): 788–800. http://dx.doi.org/10.1094/phyto.2000.90.8.788.
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A general approach was developed to predict the yield loss of crops in relation to infection by systemic diseases. The approach was based on two premises: (i) disease incidence in a population of plants over time can be described by a nonlinear disease progress model, such as the logistic or monomolecular; and (ii) yield of a plant is a function of time of infection (t) that can be represented by the (negative) exponential or similar model (ζ(t)). Yield loss of a population of plants on a proportional scale (L) can be written as the product of the proportion of the plant population newly infected during a very short time interval (X′(t)dt) and ζ(t), integrated over the time duration of the epidemic. L in the model can be expressed in relation to directly interpretable parameters: maximum per-plant yield loss (α, typically occurring at t = 0); the decline in per-plant loss as time of infection is delayed (γ; units of time-1); and the parameters that characterize disease progress over time, namely, initial disease incidence (X0), rate of disease increase (r; units of time-1), and maximum (or asymptotic) value of disease incidence (K). Based on the model formulation, L ranges from αX0 to αK and increases with increasing X0, r, K, α, and γ-1. The exact effects of these parameters on L were determined with numerical solutions of the model. The model was expanded to predict L when there was spatial heterogeneity in disease incidence among sites within a field and when maximum per-plant yield loss occurred at a time other than the beginning of the epidemic (t > 0). However, the latter two situations had a major impact on L only at high values of r. The modeling approach was demonstrated by analyzing data on soybean yield loss in relation to infection by Soybean mosaic virus, a member of the genus Potyvirus. Based on model solutions, strategies to reduce or minimize yield losses from a given disease can be evaluated.
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Andrade-Piedra, Jorge L., Robert J. Hijmans, Henry S. Juárez, Gregory A. Forbes, Dani Shtienberg, and William E. Fry. "Simulation of Potato Late Blight in the Andes. II: Validation of the LATEBLIGHT Model." Phytopathology® 95, no. 10 (October 2005): 1200–1208. http://dx.doi.org/10.1094/phyto-95-1200.
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LATEBLIGHT, a mathematical model that simulates the effect of weather, host growth and resistance, and fungicide use on asexual development and growth of Phytophthora infestans on potato foliage, was validated for the Andes of Peru. Validation was needed due to recent modifications made to the model, and because the model had not been formally tested outside of New York State. Prior to validation, procedures to estimate the starting time of the epidemic, the amount of initial inoculum, and leaf wetness duration were developed. Observed data for validation were from field trials with three potato cultivars in the Peruvian locations of Comas and Huancayo in the department of Junín, and Oxapampa in the department of Pasco in 1999 and 2000 for a total of 12 epidemics. These data had not been used previously for estimating model parameters. Observed and simulated epidemics were compared graphically using disease progress curves and numerically using the area under the disease progress curve in a confidence interval test, an equivalence test, and an envelope of acceptance test. The level of agreement between observed and simulated epidemics was high, and the model was found to be valid according to subjective and objective performance criteria. The approach of measuring fitness components of potato cultivars infected with isolates of a certain clonal lineage of P. infestans under controlled conditions and then using the experimental results as parameters of LATEBLIGHT proved to be effective. Fungicide treatments were not considered in this study.
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Workneh, F., D. C. Henne, A. C. Childers, L. Paetzold, and C. M. Rush. "Assessments of the Edge Effect in Intensity of Potato Zebra Chip Disease." Plant Disease 96, no. 7 (July 2012): 943–47. http://dx.doi.org/10.1094/pdis-06-11-0480.
Full textAbstract:
Zebra chip is a newly emerging potato disease which imparts dark colorations on fried chips, rendering them unmarketable. The disease is associated with the phloem-limited proteobacterium ‘Candidatus Liberibacter solancearum’, vectored by the potato psyllid Bactericera cockerelli. First reported from Mexico in the mid-1990s, the disease was observed for the first time in Texas in 2000 and is now prevalent in several potato-producing regions of the United States. In this study, we were interested in investigating whether there are edge effects in zebra chip intensity that can be assessed as a “foot print” of the associated insect vector. In 2009, we conducted studies in three fields in the Texas Panhandle in paired plots of 10 by 20 m around the field edges and 100 m infield in which symptomatic plants were counted just before harvest. The number of plot pairs (edge and infield) ranged from 15 to 18 depending on the size of the fields. In a separate study, temporal disease progress was assessed in two fields around the edges of the center-pivot circle in approximately 10-by-450-m areas. In 2010, the paired plot studies were repeated in 10 potato fields in Texas, Kansas, and Nebraska. Zebra chip intensity data from the paired-plot studies for both years were analyzed using the Wilcoxon's signed-rank test, a nonparametric equivalent of the classical (parametric) paired t test. In the 2009 study in all three fields, the edge plots had significantly greater zebra chip intensity than the infield plots (P < 0.05). Edge plots in the 2010 study also had greater zebra chip intensity in all fields and the differences were significant in the majority of fields (P < 0.05). In the diseases progress study in both fields, weekly zebra chip intensity on the edges reached its maximum after the third week of its first detection, and the disease progress curves were best fitted with the second-degree polynomial (quadratic) for both fields. The 2-year study clearly demonstrated that zebra chip intensity in potato fields was greater on the edges than in the infields. This finding has significant implications for psyllid management because greater emphasis in psyllid control strategy can be directed toward the edges for better results.
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Viriyasuthee, Saksirirat, Saepaisan, Gleason, and Jogloy. "Variability of Alternaria Leaf Spot Resistance in Jerusalem Artichoke (Helianthus Tuberosus L.) Accessions Grown in a Humid Tropical Region." Agronomy 9, no. 6 (May 28, 2019): 268. http://dx.doi.org/10.3390/agronomy9060268.
Full textAbstract:
Alternaria leaf spot is an emerging disease of Jerusalem artichoke (Helianthus tuberosus L.) in tropical regions. The lack of known resistant germplasm sources is an important constraint to development of Jerusalem artichoke varieties with resistance to Alternaria leaf spot. The objectives of this study were to identify variability of Jerusalem artichoke genotypes for resistance to Alternaria leaf spot under field conditions and to investigate the relationships among resistance characters, yield, and yield components for selection of resistant varieties. Ninety six accessions of Jerusalem artichoke were evaluated in replicated trials under field conditions in early rainy and late rainy seasons in Khon Kaen, Thailand during 2014. Parameters evaluated included disease incidence, disease score, disease severity index, area under disease progress curve of disease incidence, area under disease progress curve of disease severity index, number of tubers/plants, tuber size, and fresh tuber yield. The genotypes HEL 335, HEL 256, HEL 317, HEL 308, and JA 86 were identified as sources of leaf spot resistance in both seasons. These genotypes can be used as sources of leaf spot resistance for Jerusalem artichoke breeding programs. HEL 293 and HEL 246 showed susceptibility to leaf spot disease in both seasons and should be used as standard susceptible checks.
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Gongora-Canul, C., J. D. Salgado, D. Singh, A. P. Cruz, L. Cotrozzi, J. Couture, M. G. Rivadeneira, et al. "Temporal Dynamics of Wheat Blast Epidemics and Disease Measurements Using Multispectral Imagery." Phytopathology® 110, no. 2 (February 2020): 393–405. http://dx.doi.org/10.1094/phyto-08-19-0297-r.
Full textAbstract:
Wheat blast is a devastating disease caused by the Triticum pathotype of Magnaporthe oryzae. M. oryzae Triticum is capable of infecting leaves and spikes of wheat. Although symptoms of wheat spike blast (WSB) are quite distinct in the field, symptoms on leaves (WLB) are rarely reported because they are usually inconspicuos. Two field experiments were conducted in Bolivia to characterize the change in WLB and WSB intensity over time and determine whether multispectral imagery can be used to accurately assess WSB. Disease progress curves (DPCs) were plotted from WLB and WSB data, and regression models were fitted to describe the nature of WSB epidemics. WLB incidence and severity changed over time; however, the mean WLB severity was inconspicuous before wheat began spike emergence. Overall, both Gompertz and logistic models helped to describe WSB intensity DPCs fitting classic sigmoidal shape curves. Lin’s concordance correlation coefficients were estimated to measure agreement between visual estimates and digital measurements of WSB intensity and to estimate accuracy and precision. Our findings suggest that the change of wheat blast intensity in a susceptible host population over time does not follow a pattern of a monocyclic epidemic. We have also demonstrated that WSB severity can be quantified using a digital approach based on nongreen pixels. Quantification was precise (0.96 < r> 0.83) and accurate (0.92 < ρ > 0.69) at moderately low to high visual WSB severity levels. Additional sensor-based methods must be explored to determine their potential for detection of WLB and WSB at earlier stages.
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Silveira, José R. P., Valmir Duarte, Marcelo G. Moraes, Carlos A. Lopes, José M. Fernandes, Valmor Barni, and João L. N. Maciel. "Epidemiological analysis of clones and cultivars of potato in soil naturally infested with Ralstonia solanacearum biovar 2." Fitopatologia Brasileira 32, no. 3 (June 2007): 181–88. http://dx.doi.org/10.1590/s0100-41582007000300001.
Full textAbstract:
The objectives of this study were to evaluate the progress of Ralstonia solanacearum bacterial potato wilt biovar 2 (race 3) in 14 potato (Solanum tuberosum L.) cultivars or clones, the resistance of potato clone MB 03 (selected in Brasília, Brazil) to race 1 of R. solanacearum, and the occurrence of the pathogen in tubers harvested from asymptomatic potato plants. During the spring (September to the end of November in the southern hemisphere) of 1999 and 2000, 14 cultivars or clones were grown in a field naturally infested with R. solanacearum biovar 2, in Caxias do Sul, RS. The number of wilted potato plants was recorded each week and a disease progress curve plotted, the resistance of the potato genotypes to bacterial wilt being evaluated by determining the area under the curve. Various models were evaluated to fit the curves, with the logistic model being the best fit. At the end of each growing season tubers produced by asymptomatic plants were harvested and stored until budding and then tested for the presence of R. solanacearum. Cultivar Cruza 148 and clone MB 03 were the most resistant but both showed tubers with latent infections. The epidemiological implications of the incidence of R. solanacearum biovar 2 (race 3) in potato crops, as well as the resistance of certain genotypes that may harbor latent infections, are important aspects to be considered in the integrated management of bacterial wilt.
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Du, Ruoyun. "Research progress of EMT in Cancer Metastasis." E3S Web of Conferences 245 (2021): 03049. http://dx.doi.org/10.1051/e3sconf/202124503049.
Full textAbstract:
Cancer is still a deadly disease that haunts people. Once there is a malignant tumor, patients need to receive a series of expensive, complex and painful treatments. Even so, cancer still causes high mortality, for its ability to easily metastasizing to other organs, without effective cures for any kind of cancer so far. Therefore, researchers have been trying to explore its mechanism and find ways to inhibit its development and discover new cure from various aspects. The latest research found that Epithelial-Mesenchymal Transitions (EMT) may be related to cancer, especially in the metastasis. It can be a breakthrough finding that render cancer a curable disease. In this paper, we systematically introduce the definition, classification, mechanism, influencing factors of EMT and its relationship with cancer metastasis and provide new angles and ideas for further exploring all levels of signal pathways and cancer treatment.
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Narouei-Khandan, Hossein A., Shankar K. Shakya, Karen A. Garrett, Erica M. Goss, Nicholas S. Dufault, Jorge L. Andrade-Piedra, Senthold Asseng, Daniel Wallach, and Ariena H. C. van Bruggen. "BLIGHTSIM: A New Potato Late Blight Model Simulating the Response of Phytophthora infestans to Diurnal Temperature and Humidity Fluctuations in Relation to Climate Change." Pathogens 9, no. 8 (August 15, 2020): 659. http://dx.doi.org/10.3390/pathogens9080659.
Full textAbstract:
Temperature response curves under diurnal oscillating temperatures differ from those under constant conditions for all stages of the Phytophthora infestans infection cycle on potatoes. We developed a mechanistic model (BLIGHTSIM) with an hourly time step to simulate late blight under fluctuating environmental conditions and predict late blight epidemics in potato fields. BLIGHTSIM is a modified susceptible (S), latent (L), infectious (I) and removed (R) compartmental model with hourly temperature and relative humidity as driving variables. The model was calibrated with growth chamber data covering one infection cycle and validated with field data from Ecuador. The model provided a good fit to all data sets evaluated. There was a significant interaction between average temperature and amplitude in their effects on the area under the disease progress curve (AUDPC) as predicted from growth chamber data on a single infection cycle. BLIGHTSIM can be incorporated in a potato growth model to study effects of diurnal temperature range on late blight impact under climate change scenarios.
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Gangwar, Gokil Prasad. "Effect of bioagent formulations on progress of bacterial leaf blight disease of rice under field conditions." Journal of Applied and Natural Science 5, no. 2 (December 1, 2013): 388–93. http://dx.doi.org/10.31018/jans.v5i2.338.
Full textAbstract:
In the present study, effectiveness of different fungal (Trichoderma harzianum) and bacterial (Pseudomonas fluorescens) bioagent formulations in reducing progress of the bacterial leaf blight disease of rice under field conditions was studied and compared with chemical treatment and untreated check. The results exhibited that after 23 to 30 days after first application, bioagent formulations were more effective then chemical treatment in reducing progress of disease. Bioagent formulations exhibited long lasting effect in reducing progress of disease during Kharif, 2006 and 2007. Application of bioagent formulations resulted in significant reduction (60.5 – 142.8%) in area under disease progress curve (AUDPC) as compared to check during Kharif, 2006 and 2007. Significant increase in grain yield (14.3 - 21.5 %) was observed with the application of bioagent formulations as compared to check during Kharif, 2006 and 2007.