Progression of root rot on processing carrots due toSclerotium rolfsiiand the relationship of disease incidence to inoculum density

1986 ◽  
Vol 8 (3) ◽  
pp. 297-304 ◽  
Author(s):  
Zamir K. Punja
Keyword(s):  
Root Rot ◽  
Disease Incidence ◽  
Inoculum Density ◽  
Relationship Of ◽  
The Relationship

Cylindrocladium root rot in Ontario bare-root nurseries: estimate of spruce seedling losses

1988 ◽  
Vol 18 (11) ◽  
pp. 1493-1496 ◽  
Author(s):  
J. Juzwik ◽  
C. Honhart ◽  
N. Chong
Keyword(s):  
Visual Field ◽  
Root Rot ◽  
Disease Incidence ◽  
White Spruce ◽  
Visual Assessment ◽  
Inoculum Density ◽  
Field Assessment ◽  
Causal Fungus ◽  
Bare Root ◽  
Apparently Healthy

Estimates of cylindrocladium root rot losses in three black and three white spruce compartments at five Ontario bare-root nurseries were determined through visual field assessment and seedling isolation. The causal fungus, Cylindrocladiumfloridanum Sob. & C.P. Seym., was isolated from 10–77% of the symptomatic and 0–28% of the apparently healthy seedlings in each compartment. In five compartments, estimates of mean incidence based on seedling isolations and visual assessment, were higher than those based on visual assessment alone. The percentage of living spruce (apparently healthy or symptomatic) estimated to be infected in each compartment was 0.1–32.7%. No fungus isolations were attempted from dead seedlings. Mortality in the plots in the six compartments was 0.02–17.7%. The correlation between the level of Cylindrocladium incidence and the inoculum density was significant (p < 0.01) in two compartments. The use of inoculum density to predict disease incidence warrants further investigation.

Relationship of Rhizoctonia solani inoculum density to incidence of hypocotyl rot and damping-off in dry beans

1989 ◽  
Vol 35 (12) ◽  
pp. 1132-1140 ◽  
Author(s):  
A. J. L. Phillips
Keyword(s):  
Phaseolus Vulgaris ◽  
Linear Regression ◽  
Rhizoctonia Solani ◽  
Disease Incidence ◽  
Inoculum Density ◽  
Damping Off ◽  
Dry Beans ◽  
Site Model ◽  
Relationship Of

The effect of inoculum density on preemergence disease incidence was described by linear regression. Variations in virulence among 10 isolates formed a continuum. The effect of inoculum density on hypocotyl disease incidence was described by a limiting site model and variations in virulence among the isolates also formed a continuum. The ability of an isolate to cause preemergence disease was not necessarily related to its ability to cause hypocotyl disease. Both saprophytic colonization and preemergence infection arose from propagules in the spermosphere, while depending on the isolate, infection of hypocotyls was from propagules in either the rhizosphere or the rhizoplane. The observed number of hypocotyl lesions was greater than that estimated from the percentage of plants infected. This effect was more pronounced when seeds were sown at 4 than at 1 cm depth.Key words: beans, epidemiology, Phaseolus vulgaris, Rhizoctonia solani.

scholarly journals A Pictorial Disease Severity Key and the Relationship Between Severity and Incidence for Black Root Rot of Pansy Caused by Thielaviopsis basicola

Plant Disease ◽  
2008 ◽  
Vol 92 (10) ◽  
pp. 1394-1399 ◽  
Author(s):  
Warren E. Copes ◽  
Katherine L. Stevenson
Keyword(s):  
Disease Severity ◽  
Root Rot ◽  
Disease Incidence ◽  
Predictive Ability ◽  
Reliable Estimate ◽  
Regression Equations ◽  
Thielaviopsis Basicola ◽  
Black Root Rot ◽  
Fertility Treatments ◽  
The Relationship

A pictorial key was developed and the relationship between disease severity (S) and incidence (I) was examined to aid in the assessment of black root rot of pansy caused by Thielaviopsis basicola. The key consisted of photographs of root segments that represented nine disease severity levels ranging from 1 to 91%. Pansies that had received different fertility treatments, as part of seven separate experiments, were inoculated with T. basicola. Four weeks after inoculation, roots were washed, and incidence and severity of black root rot were visually assessed using a grid-line-intersect method. Disease incidence ranged from 1.3 to 100%, and severity ranged from 0.1 to 21.4% per plant. Four different mathematical models were compared to quantitatively describe the I-S relationship for the combined data from all seven experiments. Although all models provided an adequate fit, the model that is analogous to the Kono-Sugino equation provided the most reliable estimate of severity over the entire range of disease incidence values. The predictive ability and accuracy of this model across data sets was verified by jackknife and cross-validation techniques. We concluded that incidence of black root rot in pansy can be assessed more objectively and with greater precision than disease severity and can be used to provide reliable estimates of disease severity based on derived regression equations that quantify the I-S relationship for black root rot.

scholarly journals Inoculum Density-Disease Development Relationship in Verticillium Wilt of Artichoke Caused by Verticillium dahliae

Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1131-1136 ◽  
Author(s):  
M. Berbegal ◽  
A. Ortega ◽  
J. García-Jiménez ◽  
J. Armengol
Keyword(s):  
Population Dynamics ◽  
Verticillium Dahliae ◽  
Symptom Severity ◽  
Disease Incidence ◽  
Growing Season ◽  
Inoculum Density ◽  
Disease Development ◽  
Growing Seasons ◽  
Negative Exponential ◽  
The Relationship

The relationship between inoculum density of Verticillium dahliae in soil and disease development was studied in 10 commercial artichoke fields. Inoculum density of V. dahliae varied between 2.2 and 34.2 microsclerotia (ms) g–1 of soil near planting. Artichoke plants were monitored for disease at the beginning and the end of each growing season. There was a significant correlation, which was best described by negative exponential models, between inoculum density and disease incidence, symptom severity, and recovery of the pathogen from the plants. Inoculum densities ranging from 5 to 9 ms g–1 of soil were associated with a mean percentage of infected plants of about 50%. Additionally, three fields were monitored in two consecutive growing seasons to evaluate the population dynamics of V. dahliae microsclerotia in soil and disease development. Numbers of microsclerotia per gram of soil decreased significantly by the end of the first growing season but slightly increased at the end of the second growing season. In these fields, symptom severity was greatest during the second growing season when high percentages of infected plants also were recorded.

scholarly journals HUBUNGAN SANITASI RUMAH DENGAN KEJADIAN PENYAKIT TUBERKULOSIS (TB) DI KECAMATAN KUTA

2017 ◽  
Vol 11 (1) ◽  
pp. 55
Author(s):  
I Made Mudana ◽  
Nyoman Adiputra ◽  
I.B.G. Pujaastawa
Keyword(s):  
Disease Incidence ◽  
Control Group ◽  
Case Group ◽  
Residential Density ◽  
Independent Variables ◽  
Regression Test ◽  
House Floor ◽  
Relationship Of ◽  
The Relationship ◽  
Logistic Regression Test

RELATIONSHIP HOUSING SANITATION WITH TUBERCULOSIS DISEASES (TB) INCIDENCE IN KUTA DISTRICTOne of the endemic infectious diseases occured in the community is tuberculosis (TB). The World Health Organization (WHO) estimated about one third of the world's population has been infected by the bacteria mycobacterium tuberculosis. Badung regency as one of the districts in the province of Bali also having cases of tuberculosis. From the report Badung Health Agency in 2015 was recorded 275 TB patients. From 6 districts in Badung district, subdistrict of Kuta occupy the highest number of cases recorded 100 patients. tuberculosis is closely related to homes sanitation that do not meet health requirements. The purpose of this study was to determine the relationship of home sanitation with disease incidence of tuberculosis in the district of Kuta. Based on the type of research is observational analytic, design research is a case control studies linking ie risk factors. (Home sanitation) with TB disease events, by comparing the case group and the control group. The population in this study are patients with TB BTA (+) were treated working area Puskesmas Kuta I and Puskesmas Kuta II sanitation as well as his home. The number of samples in this study was 60 consisting of the case group and the control group. How sampling is the total population of TB patients in the last 3 months of 2015 as well as sanitary home. Data collected from interviews, observations and measurements and then analyzed using chi square and followed by multiple logistic regression test. From the statistic test bivariate home sanitation  with tuberculosis disease incidence 6 variables showed that: (1) lighting p = 0,00 (p< 0,05) OR = 21, (2) humidity p = 0,00 (p< 0,05) OR = 21,36 , (3) ventilation p = 0,00 (p< 0,05)OR = 11, (4) the walls of the house p = 0,00 (p< 0,05) OR = 8,64, (5) density residential home p = 0,00 (p<0,05) OR = 16,43 and (6) house floor p = 0,22 (p>0,05) OR = 2,143. To determine the relationship of all independent variables simultaneously multivariate analysis with multiple logistic regression test. Based on the results obtained that there are three independent variables significantly related (p<0,05) with the dependent variable is the humidity (OR = 19,158, 95% CI 3,171 –115,751), ventilation (OR = 6,408, 95% CI = 1,199 to 34,236), residential density (OR = 13,342, 95% CI = 2,261 – 78,733). Probability of people who occupy the house with sanitation (Humidity, Ventilation and Residential density) in the district of Kuta to contract tuberculosis (TB) is 97,08%. Based on these results, we can conclude that from the test bivariate (6 variables) are: lighting, humidity, ventilation, walls of houses, residential density and house floor associated with the incidence of tuberculosis in the district of Kuta. While the advice may be given to: (1). people who live in the district of Kuta in order to build or occupy a dwelling house to take into account the standard of sanitation and healthy home. (2). Government / agencies in order to provide guidance to the public in order to build houses of spatial attention and care homes that meet health requirements so that people who lived in the house to feel safe, comfortable, and avoid the disease especially those stemming from poor sanitation home.

Effects of laminated root rot (Phellinusweirii) on Douglas-fir foliar chemistry

1996 ◽  
Vol 26 (8) ◽  
pp. 1440-1445 ◽  
Author(s):  
A.J. Thomson ◽  
D.G. Goodenough ◽  
H.J. Barclay ◽  
Y.J. Lee ◽  
R.N. Sturrock
Keyword(s):  
Chlorophyll A ◽  
Root Rot ◽  
Statistical Significance ◽  
Douglas Fir ◽  
Foliar Chemistry ◽  
Chlorophyll A And B ◽  
Foliage Chemistry ◽  
Relationship Of ◽  
The Relationship ◽  
Made In

To determine the effects of laminated root rot (Phellinusweirii) on Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) foliar chemistry, chlorophyll a and b, N, P, K, Ca, Mg, Mn, Fe, and foliage moisture were measured in new and old foliage from 20- to 80-year-old coastal Douglas-fir. Measurements were made in June and September of 1993 and June of 1994. Chlorophyll a and b, Ca, Fe, Mg, and Mn were higher in old foliage in both June and September, while moisture, N, and K were higher in the new foliage. The relationship of P to foliage age changed with time. Reductions in foliage moisture, chlorophyll a, and N were consistently associated with P. weirii infection in all plots, but the normal high variability in foliage chemistry made demonstration of statistical significance difficult. Within-tree variability in foliar chemistry was much higher in June than in September, especially in the new foliage.

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