FACTORS AFFECTING THE DISTRIBUTION, INCIDENCE AND SPREAD OF FUSARIUM WILT OF COTTON IN TANZANIA

2002 ◽  
Vol 38 (1) ◽  
pp. 13-27 ◽  
Author(s):  
R. J. Hillocks ◽  
T. H. M. Kibani
Keyword(s):  
Fusarium Wilt ◽  
Disease Incidence ◽  
Economic Liberalization ◽  
Disease Spread ◽  
Root Knot Nematode ◽  
Agricultural Export ◽  
Factors Affecting ◽  
Source Of Infection ◽  
Seed Distribution ◽  
Phytosanitary Measures

Cotton (Gossypium hirsutum) is the main agricultural export commodity from Tanzania. The most significant disease of the crop is fusarium wilt caused by Fusarium oxysporum f.sp. vasinfectum. Phytosanitary measures instituted at the cotton ginneries to prevent the distribution, for planting, of seed infected with the wilt fungus have become difficult to apply since economic liberalization and the entry of the private sector into cotton ginning and lint marketing. Surveys of cotton fields, ginneries and cotton buying posts were conducted in order to determine the factors affecting disease incidence and spread. In affected fields, disease incidence was generally less than 5%. Where it was greater than this, wilt symptoms were associated with root damage caused by the root-knot nematode (Meloidogyne incognita). At a number of ginneries, herdsmen were allowed to remove seed husks that accumulate at the ginneries as a byproduct of oil extraction. The husks are used as cattle feed and this was identified as a potential source of disease spread. At the buying posts visited, there was no system for separating cotton varieties or for identifying seed cotton purchased from villages infected with fusarium wilt. As a result, seed subsequently distributed for planting is likely to be a source of infection for the spread of this disease. The implications of economic liberalization in the cotton sector are discussed with respect to seed distribution and management of fusarium wilt.

Understanding Economic and Health Factors Impacting the Spread of COVID-19 Disease (Preprint)

2020 ◽  
Author(s):  
Aleksandr Farseev ◽  
Yu-Yi Chu-Farseeva ◽  
Yang Qi ◽  
Daron Benjamin Loo
Keyword(s):  
Public Health ◽  
Quantitative Research ◽  
Health Indicators ◽  
Initial Study ◽  
Disease Spread ◽  
Factors Affecting ◽  
Country Level ◽  
Development Scenarios ◽  
Health Factors ◽  
Country Clusters

UNSTRUCTURED The rapid spread of the Coronavirus 2019 disease (COVID-19) had drastically impacted life all over the world. While some economies are actively recovering from this pestilence, others are experiencing fast and consistent disease spread, compelling governments to impose social distancing measures that have put a halt on routines, especially in densely-populated areas. Aiming at bringing more light on key economic and public health factors affecting the disease spread, this initial study utilizes a quantitative statistical analysis based on the most recent publicly-available COVID-19 datasets. The study had shown and explained multiple significant relationships between the COVID-19 data and other country-level statistics. We have also identified and statistically profiled four major country-level clusters with relation to different aspects of COVID-19 development and country-level economic and health indicators. Specifically, this study has identified potential COVID-19 under-reporting traits as well as various economic factors that impact COVID-19 Diagnosis, Reporting, and Treatment. Based on the country clusters, we have also described the four disease development scenarios, which are tightly knit to country-level economic and public health factors. Finally, we have highlighted the potential limitation of reporting and measuring COVID-19 and provided recommendations on further in-depth quantitative research.

Biological control of Fusarium wilt of cucumber with nonpathogenic isolates of Fusarium oxysporum

1987 ◽  
Vol 33 (5) ◽  
pp. 349-353 ◽  
Author(s):  
T. C. Paulitz ◽  
C. S. Park ◽  
R. Baker
Keyword(s):  
Biological Control ◽  
Fusarium Oxysporum ◽  
Infection Rate ◽  
Fusarium Wilt ◽  
Disease Incidence ◽  
Infection Rates ◽  
Control Activity ◽  
Significant Difference ◽  
Cucumber Roots ◽  
Linear Regressions

Nonpathogenic isolates of Fusarium oxysporum were obtained from surface-disinfested, symptomless cucumber roots grown in two raw (nonautoclaved) soils. These isolates were screened for pathogenicity and biological control activity against Fusarium wilt of cucumber in raw soil infested with Fusarium oxysporum f. sp. cucumerinum (F.o.c.). The influence of three isolates effective in inducing suppressiveness and three ineffective isolates on disease incidence over time was tested. The effective isolates reduced the infection rate (R), based on linear regressions of data transformed to loge (1/1 – y). Effective isolate C5 was added to raw soil infested with various inoculum densities of F.o.c. In treatments without C5, the increase in inoculum densities of F.o.c. decreased the incubation period of wilt disease, but there was no significant difference in infection rate among the inoculum density treatments. Isolate C5 reduced the infection rate at all inoculum densities of F.o.c. Various inoculum densities of C5 were added to raw soils infested with 1000 cfu/g of F.o.c. In the first trial, infection rates were reduced only in the treatment with 10 000 cfu/g of C5; in the second trial, infection rates were reduced in treatments with 10 000 and 30 000 cfu/g of C5.

STUDIES ON THE SEEDLING DISEASE OF BARLEY CAUSED BY HELMINTHOSPORIUM SATIVUM P.K. & B.

1956 ◽  
Vol 34 (4) ◽  
pp. 653-673 ◽  
Author(s):  
R. A. Ludwig ◽  
R. V. Clark ◽  
J. B. Julien ◽  
D. B. Robinson
Keyword(s):  
Disease Incidence ◽  
Infested Soil ◽  
Disease Development ◽  
Toxic Activity ◽  
Factors Affecting ◽  
Seedling Disease ◽  
Nutrient Salt ◽  
Helminthosporium Sativum ◽  
Treatment Comparisons

A standard sand – cornmeal – nutrient salt medium, for use in the production of artificial inoculum of Helminthosporium sativum, is described. This inoculum induces uniform plant disease development when thoroughly incorporated with the planting soil. The results presented clearly demonstrate the necessity of using a series of infestation levels in studies of factors affecting disease development in artificially infested soil. It is shown that considerable reliance can be placed on treatment comparisons within an experiment but that comparisons between experiments are much less accurate. The role of a toxin (or toxins) in disease development in barley seedlings has been demonstrated. The toxic activity was found to be distinct from that frequently encountered on addition of organic matter to soil. Results obtained suggest that toxin adsorption by the soil may play an important role in reducing disease incidence and severity.

Sources of resistance to Fusarium wilt and root-knot nematode in indigenous chickpea germplasm

2012 ◽  
Vol 10 (3) ◽  
pp. 258-260 ◽  
Author(s):  
Mohar Singh ◽  
Z. Khan ◽  
Krishna Kumar ◽  
M. Dutta ◽  
Anju Pathania ◽  
...  
Keyword(s):  
Fusarium Wilt ◽  
Rating Scale ◽  
Resistance Breeding ◽  
Practical Method ◽  
Root Knot Nematode ◽  
Sources Of Resistance ◽  
Chickpea Wilt ◽  
Breeding Programmes ◽  
Race 1 ◽  
Moderately Resistant

Fusarium wilt caused by Fusarium oxysporum, Schlecht. emend. Snyd. & Hans. f. sp. ciceri is prevalent in most chickpea-growing countries and is a major devastating disease. Host plant resistance is the most practical method of disease management. Indigenous chickpea germplasm reveals a heterogeneous genetic make-up and the response of resistance to wilt is an unexplored potential source for disease resistance. There are 70 indigenous germplasm lines selected on the basis of their agronomic performance and diverse areas of collections in the country. Of these, four accessions had a highly resistant score of 1 and six had a score of 3 using a 1–9 rating scale, indicating their level of resistance to Fusarium wilt (race 4). Other germplasm accessions of chickpea were found to be moderately resistant to highly susceptible disease reaction. Likewise, the same set of germplasm was also screened for Meloidogyne incognita (race 1) using pot culture under controlled condition. Only one accession was found to be resistant to this pest. These resistant gene sources can be utilised effectively for race-specific chickpea wilt and root-knot resistance breeding programmes.

scholarly journals Performance Evaluation of Chickpea Varieties under Rainfed Condition of Dharmapuri District, Tamil Nadu, India

2020 ◽  
pp. 65-70
Author(s):  
M. Sangeetha ◽  
K. Indhumathi ◽  
P. S. Shanmugam
Keyword(s):  
Fusarium Wilt ◽  
Abiotic Factors ◽  
Disease Incidence ◽  
Wilt Disease ◽  
Cost Ratio ◽  
Net Income ◽  
Rainfed Condition ◽  
Benefit Cost Ratio ◽  
Fusarium Wilt Disease ◽  
Benefit Cost

Chickpea is an important pulse crop grown during rabi season in black soil areas of Dharmapuri District. Among the various biotic and abiotic factors, the drought stress and fusarium wilt disease incidence are the major problems that reduces the chickpea yield to a greater extent. To overcome the above problems, the varieties viz., JAKI 9218 and GBM 2 were studied in comparison with farmers practice i.e., CO 4 for identification of suitable drought and disease tolerant high yielding variety for prevailing rainfed condition. The results revealed that JAKI 9218 and GBM 2 were found promising under rainfed condition and recorded the grain yield of 1008 and 933 kg/ha as compared to 808 kg/ha in CO 4. The variety JAKI 9218 proved to be superior with a yield increase of 24.7 per cent over CO 4 and 8.04 per cent over GBM 2. The pod borer and fusarium wilt disease incidence were lower in the variety JAKI 9218. The highest net income of Rs. 22158 /- and benefit cost ratio of 2.16 was realized in JAKI 9218 and the lowest net income of Rs. 13958 /- and benefit cost ratio of 1.77 was realized in farmers practice i.e., CO 4. It is concluded from the study that the chickpea variety JAKI 9218 can be recommended for large scale cultivation under rainfed condition of Dharmapuri district for realizing higher return by the farmers.

scholarly journals EPIDEMIOLOGICAL AND EPIZOOTIC ASPECT OF LEPTOSPIROSIS EVOLUTION IN TERNOPIL REGION

2016 ◽  
Author(s):  
N. A. Vasylieva ◽  
Yu. A. Kravchuk
Keyword(s):  
Infectious Diseases ◽  
Disease Incidence ◽  
Human Infection ◽  
Farm Animals ◽  
Natural Conditions ◽  
Natural Reservoir ◽  
Source Of Infection ◽  
Regional Laboratory ◽  
Dark Ground ◽  
Different Sources

<p>Background. Ternopil region is endemic on leptospirosis. Its natural conditions (slightly alkaline or alkaline<br />soils, air temperature, sufficient rainfall) contribute to the existence of major natural reservoir of the pathogen –<br />mouse-like rodents. In the region, different serovariants of leptospira are exuded by rodents and farm<br />animals.<br />Objective. The materials of the Department of Highly Infectious Diseases of Ternopil Regional Laboratory<br />Centre of the State Sanitation and Epidemiological Service of Ukraine, Ternopil Regional Laboratory of Veterinary<br />Medicine, Clinic of Infectious Diseases of TSMU were studied.<br />Leptospiras were detected by dark ground microscopy (DFM) of blood of patients, trapped rodents and examined<br />farm animals.<br />Results. The circulating of pathogens between different sources (rodents, animals) and annual �����������disease incidence<br />evidences that new leptospira serovar are carried onto endemic area mostly by farm animals; humans<br />are infected from them through the environment sometimes in 3-5 years intervals; the further diffusion to the<br />new areas of this pathogen serovars in all kinds of the examined mouse-like rodents is noticed.<br />It is established that farm animals and rodents are competing reservoirs. To predict the future epidemiological<br />situation of leptospirosis among the humans and to improve its diagnosis the constant monitoring of the<br />population, infection and leptospira carriage among mouse-like rodent and farm animals and expanding of the<br />panel of diagnostic leptospira strains including new pathogen variants in animals is necessary.<br />Conclusions. The development of additional reservoirs in animals, with circulating of other pathogen<br />serovars among them, such as mouse-like rodents, which were previously absent in the main natural reservoir,<br />cause the change of etiological structure in human leptospirosis at the endemic areas. The range of human<br />leptospirosis pathogens and its further spreading among all kinds of rodents increased during our research. The<br />results of detection of leptospirosis pathogens among the various contingents which were studied evidence that<br />the farm animals and rodents are competing reservoirs that cause human infection through environment.<br />KEY WORDS: leptospirosis, disease incidence, source of infection, rodents, farm animals.</p>

Supplemental fumigant placement improves root-knot and Fusarium wilt management for tomatoes produced on a raised bed, plasti-culture system in Florida’s Myakka fine sand.

Plant Disease ◽  
2021 ◽  
Author(s):  
Caroline E. Land ◽  
Gary E. Vallad ◽  
Johan Desaeger ◽  
Edzard van Santen ◽  
Joseph Noling ◽  
...  
Keyword(s):  
Fusarium Wilt ◽  
Methyl Bromide ◽  
Culture System ◽  
Fine Sand ◽  
Field Application ◽  
Parasitic Nematodes ◽  
Root Knot Nematode ◽  
Fresh Market ◽  
Control Activity ◽  
Raised Bed

Fresh-market tomatoes are produced on a raised-bed, plasti-culture system that relies heavily on soil applied, pre-plant fumigants for the management of soil borne pathogens, nematodes and weeds. Since the transition from methyl bromide to alternative fumigants, growers have experienced a resurgence of several soil borne pests and pathogens, including root-knot nematode caused by Meloidogyne spp. and Fusarium wilt caused by Fusarium oxysporum f.sp. lycopersici Race 3 (FOL). This resurgence is attributed to the inability of the alternative fumigants to effectively disperse through the soil in the same manner as methyl bromide. Two supplemental fumigation strategies, the application of chloropicrin below bed edges (supplemental PIC) and broadcast, deep shank applications of 1,3-dichloropropene (deep shank 1,3-D), were evaluated in conjunction with standard raised-bed applications of Pic-Clor 60, Pic-Clor 80, and Pic 100 covered with either a virtually impermeable film (VIF) or totally impermeable film (TIF). Large plot replicated studies were conducted in two separate commercial tomato fields with a history of production losses caused by root-knot nematode and Fusarium wilt. Deep shank 1,3-D applications significantly reduced the recovery of root-knot and total parasitic nematodes across field sites prior to the preparation of raised beds. Both supplemental PIC and deep shank 1,3-D reduced root-knot galling and Fusarium wilt incidence; although, the latter supplemental treatment statistically had the greatest impact. Neither the fumigant applied within raised beds nor plastic film had a significant effect on root-knot galling or Fusarium wilt. Although both supplemental fumigation strategies had a significant effect on pest and disease pressure, neither statistically improved tomato yields based on small sub-plot harvests. Controlled lab experiments confirmed the fungicidal activity of 1,3-dichloropropene against FOL, with LD75, LD90, LD95, and LD99 corresponding to estimated field application rates of 56.1, 93.5, 121.6, 184.7 L/ha, respectively. Results demonstrate how fumigant placement can improve pest and disease control activity with current fumigant alternatives to methyl bromide; and further support the broader pesticidal activity of some chemical fumigants.

Tracking Epidemics

War Epidemics ◽  
2004 ◽  
Author(s):  
Matthew Smallman-Raynor ◽  
Andrew Cliff
Keyword(s):  
Inductive Reasoning ◽  
Added Value ◽  
Disease Spread ◽  
Epidemic Disease ◽  
Time Dynamics ◽  
Source Of Infection ◽  
German Army ◽  
Military Campaigns ◽  
Social Demographic ◽  
Medical Interest

In studies of past, present, and likely future disease distributions, the ‘added value’ provided by the geographer lies in three main areas: detecting spatial concentrations of disease; isolating the processes (environmental, social, demographic, and pathogenic) which cause these disease hotspots; and in enhancing our understanding of the space–time dynamics of disease spread. This is as true of war-related epidemics as of any others. Within geography, there is a long-standing tradition of mapping disease. In this early history, the incidence maps of yellow fever produced in 1798 are often given pride of place (Robinson, 1982). These were, however, pre-dated by maps of topics as diverse as hospital capacities and the distribution of dressing-stations on a battlefield, through to maps of pestilential swamps and other hostile medical environments. But, so far as most epidemiological reports were concerned, such maps were usually incidental. The breakthrough in disease mapping occurred in the middle of the nineteenth century with the cholera map produced by Dr John Snow to accompany the second edition of his prize-winning essay On the Mode of Communication of Cholera (1855a). What set Snow’s work apart was not the cartography (dot maps, which were a well-established cartographic device, to show the geographical distribution of individual cholera deaths), but his inductive reasoning from the map. By showing what he termed the ‘topography of the outbreak’, Snow was able to draw inferences about the central source of infection. The use of mapping as an important device for suggesting hypotheses of medical interest may be traced through to the present day. For war and disease, the classic example is the Seuchen Atlas. This atlas of epidemic disease (Zeiss, 1942–5; Anderson, 1947) was conceived by the German army as an adjunct to war, enhancing its ability to mount military campaigns. The atlas was produced as separate sheets over the years 1942–5. Its distribution was confined to military institutes and to those German university institutes involved in training medical students. The scope of the atlas was not global but confined largely to those areas where the Army High Command expected to be fighting.

scholarly journals Analysis of Patterns of Pineapple Mealybug Wilt Disease in Sri Lanka

Plant Disease ◽  
1998 ◽  
Vol 82 (8) ◽  
pp. 885-890 ◽  
Author(s):  
G. Hughes ◽  
S. Samita
Keyword(s):  
Sri Lanka ◽  
Probability Distributions ◽  
Disease Incidence ◽  
Wilt Disease ◽  
Statistical Probability ◽  
Factors Affecting ◽  
Mealybug Wilt ◽  
Field Experimentation ◽  
Pineapple Mealybug Wilt ◽  
Made In

Mealybug wilt disease of pineapple has a complicated etiology, which is not yet fully understood. As a result, assessments of the disease in the field, such as those that are made in the context of evaluation of disease control methods, are usually based on symptomatology. Field assessments, based on symptoms of mealybug wilt disease, were made in the Kurunegala and Gampaha districts of Sri Lanka. These data were fitted to statistical probability distributions as a method of summarizing the spatial pattern of disease incidence. Most plots showed aggregated patterns of diseased plants, but there were some exceptions. Summarizing patterns of disease incidence by means of fitting statistical probability distributions provides a basis for significance testing in cases where factors affecting disease incidence are the subject of field experimentation. Some examples of this methodology are given.

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