Witches' Broom disease of Lucerne. II. Field studies on factors influencing symptom expression, disease incidence, and mortality rate

1957 ◽  
Vol 8 (2) ◽  
pp. 148 ◽  
Author(s):  
K Helms
Keyword(s):  
Disease Incidence ◽  
Late Summer ◽  
Local Environment ◽  
Field Studies ◽  
Day Length ◽  
Symptom Expression ◽  
River Terraces ◽  
Factors Influencing ◽  
Incidence And Mortality ◽  
Dry Conditions

Field surveys and ratings of individual lucerne plants (Medicago sativa L.) for severity of symptom expression in the Lachlan and Murrumbidgee Valleys, N.S.W., showed that each year there was a seasonal variation in observed incidence of the disease. This was due to masking of symptoms of diseased plants in the spring. Shoots from plants with masked symptoms contained virus. Maximum symptom expression developed in the late summer and early autumn. Rainfall and temperature (for which day length and light intensity are possible alternatives) appeared to be factors influencing both time and intensity of symptom expression; during the growing season severe symptoms were associated with hot dry conditions and mild symptoms with high rainfalls. Green flowers were associated with the disease in midsummer in some but not all infected plants. Disease incidence and rate of infection were influenced by local environment; more diseased plants and more mortalities of diseased plants occurred on river terraces than on river flats. Disease incidence and rate of infection were greater in old stands and in young thin stands than in young dense stands. Witches' broom was an important factor associated with mortality of plants in 10-year-old lucerne stands in the Lachlan Valley. The minimum observed life of infected plants was less than 2 months. The maximum was 33 months in the field and 54 months in the greenhouse. The economic importance of the disease in Australia is discussed.

scholarly journals Correlations between environmental salinity levels, blood biochemistry parameters, and steroid hormones in wild juvenile American alligators (Alligator mississippiensis)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Patricia C. Faulkner ◽  
Ruth M. Elsey ◽  
David Hala ◽  
Lene H. Petersen
Keyword(s):  
Late Summer ◽  
Storm Surges ◽  
Freshwater Wetlands ◽  
Alligator Mississippiensis ◽  
Environmental Salinity ◽  
Significant Seasonal Variation ◽  
Freshwater Habitats ◽  
Dry Conditions ◽  
American Alligators ◽  
One Year

AbstractAmerican alligators (Alligator mississippiensis) inhabit freshwater wetlands that are vulnerable to salinization caused by anthropogenic alterations to freshwater flow, in addition to storm surges, sea level rise, and droughts. Salinization of coastal freshwater habitats is a growing concern in a changing climate due to increased frequency and intensity of storm surges and drought conditions. This study opportunistically sampled juvenile male and female wild alligators in various salinities each month excluding November, December, and January for one year at Rockefeller Wildlife Refuge in coastal Louisiana. Blood plasma biochemistry parameters including electrolyte levels were subsequently measured. In addition, levels of various renin–angiotensin–aldosterone system hormones, glucocorticoids, androgens, estrogens, and progestogens were analyzed using liquid chromatography and tandem mass spectrometry. Only males were sampled in hyperosmotic environments (> 10‰) during dry conditions in late summer 2018. In juvenile males, plasma Na+, Cl−, and the progestogen 17α,20β-dihydroxypregnenone were significantly and positively correlated with environmental salinity. However, variation in glucocorticoids, androgens, and estrogens were not associated with hypersaline water while sex steroids showed significant seasonal variation. This study demonstrated significant correlation of environmental salinity with electrolyte levels and a sex steroid in wild juvenile alligators, and to our knowledge represents the first measurement of 17α,20β-dihydroxypregnenone in alligators.

scholarly journals Spatial Distribution of Green Mold Foci in 30 Commercial Mushroom Crops

Plant Disease ◽  
1999 ◽  
Vol 83 (1) ◽  
pp. 71-76 ◽  
Author(s):  
D. J. Royse ◽  
K. Boomer ◽  
Y. Du ◽  
M. Handcock ◽  
P. S. Coles ◽  
...  
Keyword(s):  
Cultural Practices ◽  
Disease Incidence ◽  
Spatial Distributions ◽  
Trichoderma Spp ◽  
Nutrient Supplementation ◽  
Green Mold ◽  
Factors Influencing ◽  
Airborne Contamination ◽  
Epidemic Development ◽  
Surface Covering

Statistical analyses were performed on spatial distributions of mushroom green mold foci caused by Trichoderma spp. in 30 standard Pennsylvania doubles (743 m2 production surface) selected at random from over 900 total crops mapped. Mapped production houses were divided into four tiers of six beds each with 16 sections per bed (total = 384 sections per double). Each section contained approximately 2 m2. Green mold foci were mapped according to presence or absence in each section as they became visible during the course of the mushroom production. There was a trend toward higher disease incidence at the ends of the doubles, although this was not consistent from level to level. Spatial analysis revealed that green mold foci were more likely to occur in neighboring sections along the beds rather than above, below, or across from each other. Cultural practices that were associated with movement along the beds, i.e., nutrient supplementation, spawning, bed tamping, surface covering, etc., were considered the most likely factors influencing the incidence of green mold in spawned compost. Airborne contamination was considered a less likely source of inocula contributing to epidemic development. Sanitation practices that reduce spore loads along the beds are expected to provide the greatest degree of green mold control.

SPROUTING AND DEVELOPMENT OF YELLOW NUT SEDGE TUBERS

1977 ◽  
Vol 57 (2) ◽  
pp. 509-514 ◽  
Author(s):  
G. H. FRIESEN ◽  
A. S. HAMILL
Keyword(s):  
Root Growth ◽  
Day Length ◽  
Tuber Initiation ◽  
Soil Types ◽  
Cyperus Esculentus ◽  
Southern Ontario ◽  
Tuber Production ◽  
Dry Conditions ◽  
Top 40 ◽  
Long Photoperiod

Tubers of yellow nut sedge (Cyperus esculentus L.) were collected from four farm fields representing three soil types in southern Ontario in November of 1974 or 1975. These fields contained from 760 to 8,484 tubers/m2 in the top 40 cm of soil. Tubers extracted from these soils failed to sprout following 6 wk of storage under dry conditions, but sprouting approached 100% if previously stored under cool, moist conditions. Cool temperatures during dry storage for 90 wk reduced subsequent sprouting. Tubers sprouted as well in the greenhouse as in petri plates in a germination chamber. Root growth averaged 2 cm/day in glass-lined root boxes and tuber initiation commenced 90 days after planting. Tuber production was greatest under a short day length of 12 h or less, while shoot and root growth was stimulated by a long photoperiod.

scholarly journals Meningococcal disease epidemiology in Australia 10 years after implementation of a national conjugate meningococcal C immunization programme

2016 ◽  
Vol 144 (11) ◽  
pp. 2382-2391 ◽  
Author(s):  
G. L. LAWRENCE ◽  
H. WANG ◽  
M. LAHRA ◽  
R. BOOY ◽  
P. B. McINTYRE
Keyword(s):  
Disease Surveillance ◽  
Vaccine Coverage ◽  
Disease Incidence ◽  
Age Groups ◽  
Disease Epidemiology ◽  
Immunization Programme ◽  
Published Evidence ◽  
Incidence And Mortality ◽  
Catch Up ◽  
Vaccine Failures

SUMMARYAustralia implemented conjugate meningococcal C immunization in 2003 with a single scheduled dose at age 12 months and catch-up for individuals aged 2–19 years. Several countries have recently added one or more booster doses to their programmes to maintain disease control. Australian disease surveillance and vaccine coverage data were used to assess longer term vaccine coverage and impact on invasive serogroup C disease incidence and mortality, and review vaccine failures. Coverage was 93% in 1-year-olds and 70% for catch-up cohorts. In 10 years, after adjusting for changes in diagnostic practices, population invasive serogroup C incidence declined 96% (95% confidence interval 94–98) to 0·4 and 0·6 cases/million in vaccinated and unvaccinated cohorts, respectively. Only three serogroup C deaths occurred in 2010–2012vs.68 in 2000–2002. Four (<1/million doses) confirmed vaccine failures were identified in 10 years with no increasing trend. Despite published evidence of waning antibody over time, an ongoing single dose of meningococcal C conjugate vaccine in the second year of life following widespread catch-up has resulted in near elimination of serogroup C disease in all age groups without evidence of vaccine failures in the first decade since introduction. Concurrently, serogroup B incidence declined independently by 55%.

scholarly journals Disease Prevalence, Disease Incidence, and Mortality in the United States and in England

Demography ◽  
2010 ◽  
Vol 47 (S) ◽  
pp. S211-S231 ◽  
Author(s):  
James Banks ◽  
Alastair Muriel ◽  
James P. Smith
Keyword(s):  
United States ◽  
Disease Incidence ◽  
The United States ◽  
Disease Prevalence ◽  
Incidence And Mortality

scholarly journals Impact of insecticide resistance in Anopheles arabiensis on malaria incidence and prevalence in Sudan and the costs of mitigation

2017 ◽  
Vol 114 (52) ◽  
pp. E11267-E11275 ◽  
Author(s):  
Hmooda Toto Kafy ◽  
Bashir Adam Ismail ◽  
Abraham Peter Mnzava ◽  
Jonathan Lines ◽  
Mogahid Shiekh Eldin Abdin ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Pyrethroid Resistance ◽  
Malaria Incidence ◽  
Disease Incidence ◽  
Indoor Residual Spraying ◽  
Sub Saharan Africa ◽  
Malaria Vectors ◽  
Incidence And Mortality ◽  
Additional Protection ◽  
The Impact

Insecticide-based interventions have contributed to ∼78% of the reduction in the malaria burden in sub-Saharan Africa since 2000. Insecticide resistance in malaria vectors could presage a catastrophic rebound in disease incidence and mortality. A major impediment to the implementation of insecticide resistance management strategies is that evidence of the impact of resistance on malaria disease burden is limited. A cluster randomized trial was conducted in Sudan with pyrethroid-resistant and carbamate-susceptible malaria vectors. Clusters were randomly allocated to receive either long-lasting insecticidal nets (LLINs) alone or LLINs in combination with indoor residual spraying (IRS) with a pyrethroid (deltamethrin) insecticide in the first year and a carbamate (bendiocarb) insecticide in the two subsequent years. Malaria incidence was monitored for 3 y through active case detection in cohorts of children aged 1 to <10 y. When deltamethrin was used for IRS, incidence rates in the LLIN + IRS arm and the LLIN-only arm were similar, with the IRS providing no additional protection [incidence rate ratio (IRR) = 1.0 (95% confidence interval [CI]: 0.36–3.0; P = 0.96)]. When bendiocarb was used for IRS, there was some evidence of additional protection [interaction IRR = 0.55 (95% CI: 0.40–0.76; P < 0.001)]. In conclusion, pyrethroid resistance may have had an impact on pyrethroid-based IRS. The study was not designed to assess whether resistance had an impact on LLINs. These data alone should not be used as the basis for any policy change in vector control interventions.

Simulation of the Cooking Organic Aerosol Concentration Variability in an Urban Area

2021 ◽  
Author(s):  
Evangelia Siouti ◽  
Ksakousti Skyllakou ◽  
Ioannis Kioutsioukis ◽  
Giancarlo Ciarelli ◽  
Spyros N. Pandis
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Temporal Distribution ◽  
Late Summer ◽  
Field Studies ◽  
Organic Aerosol ◽  
Basis Set ◽  
Cooking Times ◽  
The City ◽  
Lunch Time

&lt;p&gt;Cooking operations can be an important fine PM source for urban areas. Cooking emissions are a source of pollution that has been often ignored and are not included or are seriously underestimated in urban emission inventories. However, several field studies in cities all over Europe suggest that cooking organic aerosol (COA) can be an important component of the total organic PM. In this study we propose and evaluate a methodology for the simulation of the COA concentration and its variability in space and time in an urban area. The city of Patras, the third biggest in Greece is used for this first application for a typical late summer period. The spatial distribution of COA emissions is based on the exact location of restaurants and grills, while the emissions on the meat consumption in Greece. We estimated COA emissions of 150 kg d&lt;sup&gt;-1&lt;/sup&gt; that corresponds to 0.6 g d&lt;sup&gt;-1&lt;/sup&gt; per person. The temporal distribution of COA was based on the known cooking times and the results of the past field studies in the area. Half of the daily COA is emitted during dinner time (21:00-0:00 LT), while approximately 25% during lunch time (13:00-16:00 LT). The COA is simulated using the Volatility Basis Set with a volatility distribution measured in the laboratory and is treated as semivolatile and reactive. The maximum average COA concentration during the simulation period is predicted to be 1.3 &amp;#956;g m&lt;sup&gt;-3&lt;/sup&gt; in a mainly pedestrian area with a high density of restaurants. Peak hourly COA concentrations in this area exceed 10 &amp;#956;g m&lt;sup&gt;-3&lt;/sup&gt; during several nights. The local production of secondary COA is predicted to be slow and it represents just a few percent of the total COA.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

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