scholarly journals Episodic Dynamics of Tar Spot of Annual Lespedeza Within and Among Years

Plant Disease ◽  
1997 ◽  
Vol 81 (5) ◽  
pp. 535-540 ◽  
Author(s):  
J. D. Mihail ◽  
R. L. McGraw ◽  
P. E. Verslues ◽  
S. J. Taylor
Keyword(s):  
Disease Severity ◽  
Temporal Dynamics ◽  
Disease Incidence ◽  
Spatial Dynamics ◽  
Silty Clay ◽  
Disease Dynamics ◽  
Silty Clay Loam ◽  
Row Crops ◽  
Tar Spot ◽  
Temporal And Spatial

The temporal and spatial dynamics of six tar spot epidemics were examined at two sites in mid-Missouri during 1990 to 1992. The sites, 48 km apart, differed in topography (flat versus slope), soil texture (silt loam versus silty-clay loam), and cropping history (orchard versus row crops). Temporal dynamics of disease incidence differed more among years than between sites. During 1990, temporal dynamics of the two epidemics followed a classic monotonic increase, whereas disease increase was episodic for the four epidemics observed during 1991 and 1992. Disease increase was associated with shading of the plant canopy or with the presence of dodder. Disease increase was related inversely to intercepted photosynthetically active radiation. Taken together, these observations suggest that factors that increase shading in the lespedeza canopy also increase tar spot incidence. For only two of the six epidemics was there a significant relationship between disease incidence (proportion of leaflets diseased) and disease severity (proportion of leaflet area diseased), with disease severity rarely exceeding 10%. These observations suggest that relatively low tar spot incidence may result in significant leaf losses, which would reduce lespedeza hay quality and yield. Further, this study demonstrates the importance of experimental repetition in both space and time to fully appreciate the range of disease dynamics for a single pathosystem.

scholarly journals Spatial and Temporal Dynamics of Mal Secco Disease Spread in Lemon Orchards in Israel

2020 ◽  
Vol 110 (4) ◽  
pp. 863-872
Author(s):  
Miriam Ben-Hamo ◽  
David Ezra ◽  
Helena Krasnov ◽  
Lior Blank
Keyword(s):  
Disease Severity ◽  
Temporal Dynamics ◽  
Disease Incidence ◽  
Disease Spread ◽  
Tree Structures ◽  
Spatial And Temporal Dynamics ◽  
Geographical Regions ◽  
Orchard Management ◽  
Severity Of The Disease ◽  
Mal Secco

Mal Secco is a severe disease of citrus in which the fungus Plenodomus tracheiphilus (formerly Phoma tracheiphila) penetrates the vascular system of the host. In this study, we characterized the spatial dynamics of the disease in seven lemon orchards. A representative block of trees from each orchard was evaluated monthly during 3 consecutive years. In addition, scouts assessed disease severity in 75 orchards from three different geographical regions and tested for association between disease severity and measures of orchard management, environmental factors, cultural practices, and cultivar type. We assessed disease incidence and characteristics of spatial patterns using Ripley’s K function and fitted logistic regression models for different neighboring tree structures followed by model selection methods to provide insight into the spatial and temporal dynamics of disease progress. We found different rates of disease spread in different orchards, which are most likely the result of differences in orchard management practices or less likely the result of differences in climatic conditions. There was an indication that agricultural tools contribute to spread of the disease within rows of trees. The results confirm that the lemon cultivar Interdonato is less susceptible compared with other citrus cultivars, and they suggest that the density of urban terrain surrounding each orchard is positively correlated with the severity of the disease. In contrast to our expectations, no correlation was found between the density of lemon orchards surrounding an orchard and the severity of the disease within it, which corroborates previous findings regarding the limited distribution of the disease.

Effects of Incorporating or Burning Straw, and of Different Cultivation Systems, on Winter Wheat Grown on Two Soil Types, 1985–91

1995 ◽  
Vol 124 (2) ◽  
pp. 173-194 ◽  
Author(s):  
R. D. Prew ◽  
J. E. Ashby ◽  
E. T. G. Bacon ◽  
D. G. Christian ◽  
R. J. Gutteridge ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Sandy Loam ◽  
Disease Incidence ◽  
Soil Types ◽  
Silty Clay ◽  
Clay Loam ◽  
Silty Clay Loam ◽  
Cultivation Systems ◽  
Sharp Eyespot ◽  
Take All

SUMMARYDisposal methods for straw from continuous winter wheat were tested on two soil types, a flinty silty clay loam and a sandy loam, over 7 years (1985–91). The methods tested were burnt or chopped straw in full factorial combination with four cultivation methods (tined to 10 cm, tined to 10 cm then to 20 cm; ploughed to 20 cm; tined to 10 cm then ploughed to 20 cm). Measurements were taken to determine the effects on crop establishment and growth, pest and disease incidence, and the consequent effects on yield. Another experiment (1985–91) on the flinty silty clay loam site, investigated the interactions between straw treatments (burnt, baled or chopped in plots that were all shallow cultivated to 10 cm) and five other factors; namely, time of cultivation, insecticides, molluscicides, fungicides and autumn nitrogen. All the straw x cultivation systems allowed satisfactory crops to be established but repeated incorporation of straw using shallow, non-inversion cultivations resulted in very severe grass-weed problems. Early crop growth, as measured by above-ground dry matter production, was frequently decreased by straw residues, but the effect rarely persisted beyond anthesis. Pests were not a problem and their numbers were not greatly affected either by straw or cultivation treatments, apart from yellow cereal fly which, especially on the heavier soil, was decreased by treatments which left much straw debris on the soil surface. Incorporating straw also caused no serious increases in the incidence of diseases. Indeed, averaged over all sites and years, eyespot and sharp eyespot were both slightly but significantly less severe where straw was incorporated than where it was burnt. Eyespot, and even more consistently sharp eyespot, were often more severe after ploughing than after shallow, non-inversion cultivations. Effects on take-all were complex but straw residues had much smaller effects than cultivations. Initially the disease increased most rapidly in the shallow cultivated plots but these also tended to go into the decline phase more quickly so that in the fourth year (fifth cereal crop) take-all was greater in the ploughed than in the shallow cultivated plots. On average, yields did not differ greatly with straw or cultivation systems, although there were clear effects of take-all in those years when the disease was most severe. In the last 2 years, yields were limited by the presence of grass weeds in the plots testing chopped straw incorporated by tining to 10 cm.

scholarly journals Methodological Proposal for the Study of Temporal and Spatial Dynamics during the Late Period between the Middle Ebro and the Pyrenees

Information ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 366 ◽  
Author(s):  
Leticia Tobalina Pulido
Keyword(s):  
Spatial Databases ◽  
Temporal Dynamics ◽  
Methodological Approach ◽  
Spatial Dynamics ◽  
Descriptive Statistics ◽  
Late Period ◽  
Rural Settlements ◽  
Spatial And Temporal Dynamics ◽  
Temporal And Spatial ◽  
Space Occupation

The article I present here deals with the methodological approach carried out in my PhD in which I analyzed the spatial and temporal dynamics of late rural settlements during five centuries in the southern Pyrenees area, using geographic information systems, spatial databases, and descriptive statistics to establish models of space occupation and try to determine how these vary over the different centuries.

scholarly journals Temporal and spatial dynamics in the apple flower microbiome in the presence of the phytopathogen Erwinia amylovora

2020 ◽  
Author(s):  
Zhouqi Cui ◽  
Regan B. Huntley ◽  
Quan Zeng ◽  
Blaire Steven
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Temporal Dynamics ◽  
Spatial Dynamics ◽  
Potential Interaction ◽  
Specific Gene ◽  
Large Populations ◽  
Single Flower ◽  
Temporal And Spatial ◽  
Blight Disease

AbstractPlant microbiomes have important roles in plant health and productivity. However, despite flowers being directly linked to reproductive outcomes, little is known about the microbiomes of flowers and their potential interaction with pathogen infection. Here, we investigated the temporal dynamics and spatial traits of the apple stigma microbiome when challenged with a phytopathogen Erwinia amylovora, the causal agent of fire blight disease. We profiled the microbiome from the stigmas of a single flower, greatly increasing the resolution at which we can characterize shifts in the composition of the microbiome. Individual flowers harbored unique microbiomes at the OTU level. However, taxonomic analysis of community succession showed a population gradually dominated by bacteria within the families Enterobacteriaceae and Pseudomonadaceae. Flowers inoculated E. amylovora established large populations of the phytopathogen, with pathogen specific gene counts of >3.0 × 107 in 90% of the flowers. Yet, only 42% of inoculated flowers later developed fire blight symptoms. This reveals pathogen amount on the stigma is not sufficient to predict disease outcome. Our data demonstrate that apple flowers represent an excellent model in which to characterize how plant microbiomes establish, develop, and interact with biological processes such as disease progression in an experimentally tractable plant organ.

scholarly journals Biodiversity and Spatial-Temporal Dynamics of Margalefidinium Species in Jiaozhou Bay, China

2021 ◽  
Vol 18 (21) ◽  
pp. 11637
Author(s):  
Shuya Liu ◽  
Mengjia Zhang ◽  
Yongfang Zhao ◽  
Nansheng Chen
Keyword(s):  
Temporal Dynamics ◽  
Harmful Algal Bloom ◽  
Jiaozhou Bay ◽  
Spatial Dynamics ◽  
High Genetic Diversity ◽  
Sequence Variations ◽  
Main Driver ◽  
Temporal And Spatial ◽  
Shed Light ◽  
Rule Out

Many Margalefidinium species are cosmopolitan harmful algal bloom (HAB) species that have caused huge economic and ecological damage. Despite extensive research on Margalefidinium species, the biodiversity and spatial-temporal dynamics of these species remain obscure. Jiaozhou Bay is an ideal area for HAB research, being one of the earliest marine survey areas in China. In this study, we carried out the first metabarcoding study on the temporal and spatial dynamics of Margalefidinium species using the 18S rDNA V4 region as the molecular marker and samples collected monthly at 12 sampling sites in Jiaozhou Bay in 2019. Two harmful Margalefidinium species (M. polykrikoides and M. fulvescens) were identified with potentially high genetic diversity (although we cannot rule out the possibility of intra-genome sequence variations). Both M. polykrikoides and M. fulvescens demonstrated strong temporal preference with a sharp peak of abundance in early autumn (September), but without showing strong location preference in Jiaozhou Bay. Our results revealed that temperature might be the main driver for their temporal dynamics. Knowledge of biodiversity and spatial-temporal dynamics of the Margalefidinium species may shed light on the understanding of mechanisms underlying strongly biased occurrences of Margalefidinium blooms recorded globally.

scholarly journals Bus ridership and its determinants in Beijing: A spatial econometric perspective

2022 ◽  
Author(s):  
Jiaoe Wang ◽  
Yanan Li ◽  
Jingjuan Jiao ◽  
Haitao Jin ◽  
Fangye Du
Keyword(s):  
Spatial Autocorrelation ◽  
Temporal Dynamics ◽  
Spatial Dynamics ◽  
Central Business District ◽  
Analytical Framework ◽  
Residential Areas ◽  
Basic Study ◽  
Factors Affecting ◽  
Temporal And Spatial ◽  
Business District

AbstractUnderstanding the temporal and spatial dynamics and determinants of public transport ridership play an important role in urban planning. Previous studies have focused on exploring the determinants at the station level using global models, or a local model, geographically weighted regression (GWR), which cannot reveal spatial autocorrelation at the global level. This study explores the factors affecting bus ridership considering spatial autocorrelation using the spatial Durbin model (SDM). Taking the community in Beijing as the basic study unit, this study aims to explore the temporal and spatial dynamics of bus ridership and identify its key determinants considering neighboring effects. The results show the following: (1) The temporal dynamics are quite distinct on weekdays and weekends as well as at different time slots of the day. (2) The spatial patterns of bus ridership varied across different time slots, and the hot areas are mainly located near the central business district (CBD), transport hubs, and residential areas. (3) Key determinants of bus ridership varied across weekends and weekdays and varied at different time slots per day. (4) The spatial neighboring effects had been verified. This study provides a common analytical framework for analyzing the spatiotemporal dynamics and determinants of bus ridership at the community level.

scholarly journals An Integrated Approach for Spatio-Temporal Cholera Disease Hotspot Relation Mining for Public Health Management in Punjab, Pakistan

2020 ◽  
Vol 17 (11) ◽  
pp. 3763
Author(s):  
Fatima Khalique ◽  
Shoab Ahmed Khan ◽  
Wasi Haider Butt ◽  
Irum Matloob
Keyword(s):  
Public Health ◽  
Temporal Dynamics ◽  
Complex Dynamics ◽  
Health Management ◽  
Disease Incidence ◽  
Integrated Approach ◽  
Geographic Area ◽  
Disease Dynamics ◽  
Spatio Temporal ◽  
Public Health Management

Public health management can generate actionable results when diseases are studied in context with other candidate factors contributing to disease dynamics. In order to fully understand the interdependent relationships of multiple geospatial features involved in disease dynamics, it is important to construct an effective representation model that is able to reveal the relationship patterns and trends. The purpose of this work is to combine disease incidence spatio-temporal data with other features of interest in a mutlivariate spatio-temporal model for investigating characteristic disease and feature patterns over identified hotspots. We present an integrated approach in the form of a disease management model for analyzing spatio-temporal dynamics of disease in connection with other determinants. Our approach aligns spatio-temporal profiles of disease with other driving factors in public health context to identify hotspots and patterns of disease and features of interest in the identified locations. We evaluate our model against cholera disease outbreaks from 2015–2019 in Punjab province of Pakistan. The experimental results showed that the presented model effectively address the complex dynamics of disease incidences in the presence of other features of interest over a geographic area representing populations and sub populations during a given time. The presented methodology provides an effective mechanism for identifying disease hotspots in multiple dimensions and relation between the hotspots for cost-effective and optimal resource allocation as well as a sound reference for further predictive and forecasting analysis.

Effect The Treatments of Biofertilizer and Mineral Fertilizer on Content of N P K of Soil Cultivated With Crop Corn (Zea Mays L).

2019 ◽  
Vol 9 (2) ◽  
pp. 247-256
Author(s):  
Mohammed Aajmi Salman ◽  
Jawad A. Kamal Al-Shibani
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Mineral Fertilizer ◽  
Silty Clay ◽  
Clay Loam ◽  
Potassium Fertilizer ◽  
Clay Loam Soil ◽  
Silty Clay Loam ◽  
Fall Season ◽  
Loam Soil

Beneficial microorganisms play a key role in the availability of ions minerals in the soil and use Randomized Complete Block Desing ( R.C.B.D ). The objective of this paper to the study effect of the of biofertilizer and miniral treatments on availability of NPK for crop corn zea mays L.Two types of biofertilizer are Bacterial Bacillus subtilis and Fungal Trichoderma harianum. Three levels of potassium fertilizer are (2.9533, 0.4000 and 2.9533). A field experiment in fall season of 2018 Has been conducted in silty clay loam soil. The experimental Results indicated that Bacillus and Trichoderma inoculation separately or together Have made a significant effect to increase in the availability of N P K in the soil compare to other treatments. The grain yield is where (2.9533, 0.4000 and 2.9533) of bacterial and fungal bio-fertilizer and potassium fertilizers respectively as compared to the control.

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