Anthracnose risk establishment based on age-related susceptibility of grape leaves, flowers and berries to infection by Elsinoë ampelina

Plant Disease ◽  
2021 ◽  
Author(s):  
Odile Carisse ◽  
Audrey Levasseur ◽  
Caroline Provost
Keyword(s):  
Disease Incidence ◽  
Leaf Age ◽  
Seasonal Development ◽  
Degree Days ◽  
Phenological Stages ◽  
Age Related ◽  
Full Flowering ◽  
Exponential Decay Model ◽  
Young Leaves ◽  
Elsinoe Ampelina

Anthracnose is an important disease of grapevines caused by the fungus Elsinoë ampelina. In recent years, there have been regular outbreaks in humid grape-growing regions around the world. Young leaves and berries are reported to be highly susceptible to E. ampelina, but detailed and seasonal development of age-related susceptibility remains unclear. Experiments were conducted under greenhouse and vineyard conditions by inoculating 1 to-19-day-old leaves, flowers and berries at different phenological stages of three grapevine cultivars (Vandal-Cliche, Marquette and Vidal). Leaf susceptibility was highest when inoculated at 1-2 days old, and inoculated leaves were moderately susceptible at 3-6 days old and almost resistant when older than 6 days. The influence of leaf age on anthracnose relative severity was adequately described by an exponential decay model. The susceptibility of the inflorescences was high when inoculated from their initiation to the full flowering (50% fall of the caps), and the inflorescences/flowers were moderately susceptible until veraison, after which the berries were practically resistant. The flower/berry susceptibility as a function of degree-days accumulated since April 1 was modeled using a sigmoid model. Based on this model, 50% disease incidence is reached when 656, 543 and 550 degree days are accumulated for the cultivars Vandal-Cliche, Marquette and Vidal, respectively. These results suggest that the risk of anthracnose development is high from bud-break to fruit set, and on newly-emerged leaves either early in the season or following pruning. More knowledge on anthracnose epidemiology is needed, but these results could be used to improve timing of fungicide applications and pruning activities.

scholarly journals Modeling Leaf Age-Related Susceptibility and Rust Eruption Dynamics in Peanut

2000 ◽  
Vol 27 (1) ◽  
pp. 7-10 ◽  
Author(s):  
Z. Z. Wang ◽  
K. H. Lin
Keyword(s):  
Leaf Age ◽  
Relative Number ◽  
Eruption Dynamics ◽  
Infection Frequency ◽  
Degree Days ◽  
Age Related ◽  
Relationship Of ◽  
The Relationship ◽  
Field Inoculum ◽  
Over Time

Abstract To improve simulation of epidemics of peanut rust, information on the effects of leaf age and pustule eruption dynamics is needed. An analysis was made of the change of leaf susceptibility of rust with leaf aging using plants exposed to field inoculum. The youngest leaf was most susceptible to rust infection. As leaves aged, susceptibility decreased quickly. The relationship of infection frequency (Y, relative number of pustules) to leaf age (X, leaf position downward on the main stem) was described by a mathematical model Y = 2.17X(-0.83). The dynamics of pustule eruption also was studied using artificial inoculation. Analysis showed that after inoculation, pustule eruption over time was distributed in a logistic pattern. Rust eruption began at 130 and reach a peek at 250 rust degree days—that is, between 7 and 15 d after inoculation. Mathematical models of leaf age-related susceptibility and rust eruption dynamics will be incorporated into simulation model of rust epidemics.

scholarly journals Epidemiology of Grape Anthracnose: Factors Associated with Defoliation of Grape Leaves Infected by Elsinoë ampelina

Plant Disease ◽  
2013 ◽  
Vol 97 (2) ◽  
pp. 222-230 ◽  
Author(s):  
Odile Carisse ◽  
Vincent Morissette-Thomas
Keyword(s):  
Leaf Area ◽  
Leaf Age ◽  
Severe Infection ◽  
Related Factors ◽  
Time To Death ◽  
Factors Associated ◽  
Failure Modeling ◽  
Leaf Emergence ◽  
Young Leaves ◽  
Elsinoe Ampelina

Anthracnose is a serious disease that affects several grape cultivars. Infected leaves drop prematurely, and severe epidemics result in poor or no yield. Because the factors associated with grape defoliation in vineyards with a history of anthracnose were not well known, this study was undertaken to investigate the relationship between weather-, disease-, and host-related factors and survival of leaves. From 2006 to 2008, weather, anthracnose severity, and leaf emergence were monitored in an unsprayed experimental vineyard naturally infested with Elsinoë ampelina. Each year, two to three times weekly, the number of leaves and the proportion of leaf area diseased (PLAD) were monitored on 10 vines and 2 shoots per vine, for a total of 785 leaves. Survival analysis was used to investigate the factors influencing defoliation and to model time-to-death of grape leaves. Estimated median survival time was 117 to 121 days. Based on Kaplan-Meier estimates of survival probabilities, season type, PLAD per leaf and PLAD per shoot at first assessment, duration and amount of rain at first infection, severity of infection and leaf age at first infection and at first severe infection significantly influenced leaf survival. Based on accelerated time failure modeling, using the Weibull distribution, the most significant variables were PLAD per leaf and PLAD per shoot at first assessment, leaf age at first infection, and duration of rain. Each additional percent increase in PLAD per leaf, in PLAD per shoot, or in rainy days accelerated the time-to-death of grape leaves by 2.84, 1.02, and 0.66%, respectively, whereas for each additional day of leaf age at time of first infection, there was a 2.88% deceleration of the time to death. Results suggested that to avoid premature leaf drop, disease severity should be maintained below 25% leaf area diseased, which can be achieved by sanitation measures designed to reduce inoculum levels and by applying fungicide early in the season to prevent infection of young leaves.

scholarly journals The Epidemiology of Powdery Mildew on Concord Grapes

2001 ◽  
Vol 91 (10) ◽  
pp. 948-955 ◽  
Author(s):  
David M. Gadoury ◽  
Robert C. Seem ◽  
Andrea Ficke ◽  
Wayne F. Wilcox
Keyword(s):  
Powdery Mildew ◽  
Fruit Set ◽  
Disease Incidence ◽  
The United States ◽  
Seasonal Development ◽  
Peak Period ◽  
Late Season ◽  
Stage Of Development ◽  
Concord Grapes ◽  
Moderately Resistant

Vitis labruscana ‘Concord’ is a grape cultivar widely grown in the United States for processing into juice and other grape products. Concord grapes are sporadically but sometimes severely damaged by the grape powdery mildew pathogen, Uncinula necator. Although the foliage is often reported to be moderately resistant to powdery mildew, severe fruit infection occurs in some years. We observed the seasonal development of powdery mildew on leaves, rachises, and berries of unsprayed Concord grapevines. Inoculations of flower and fruit clusters revealed a brief period of berry susceptibility and a protracted period of rachis susceptibility. The rachis remained highly susceptible to infection, and the severity of rachis infection increased throughout the growing season until the rachis formed a periderm shortly before harvest. In contrast, berries were nearly immune to infection within 2 weeks after fruit set. Rachis and berry infections were detected before the disease was observed on foliage, and the incidence of rachis and berry infection often exceeded disease incidence observed on foliage until after fruit acquired substantial ontogenic resistance. Excellent control of fruit infection, and adequate control of leaf infection, was achieved by two fungicide applications targeted at the peak period of fruit susceptibility. Although Concord is thought to be moderately resistant to powdery mildew, the rachis is highly susceptible, and may be the avenue by which prebloom infections make their way onto the developing fruit. Late-season infection of the rachis neither spread to the fruit, nor did it cause fruit to drop prematurely, and may be of little economic consequence on fruit destined for processing. Although fruit of V. vinifera cultivars have been reported to remain susceptible to infection until berry sugar levels reach 8 to 15%, Concord fruit become nearly immune to infection nearly 6 weeks before this stage of development. Because powdery mildew does not become conspicuous on foliage until late summer, it is generally regarded as a late-season problem on Concord grapes, and previous management programs have reflected this belief. However, the greatest contribution to control of fruit infection is due to fungicides applied during the peak period of fruit susceptibility, from bloom until shortly after fruit set, long before the disease is observed on foliage.

Changing Trends in Age and Sex Distributions of Lyme Disease—United States, 1992-2016

2021 ◽  
pp. 003335492110267
Author(s):  
Kiersten J. Kugeler ◽  
Paul S. Mead ◽  
Amy M. Schwartz ◽  
Alison F. Hinckley
Keyword(s):  
United States ◽  
Lyme Disease ◽  
Disease Incidence ◽  
Age Distribution ◽  
Relative Size ◽  
The United States ◽  
Male Predominance ◽  
Age Related ◽  
Over Time ◽  
Age And Sex

Lyme disease is the most common vector-borne disease in the United States and is characterized by a bimodal age distribution and male predominance. We examined trends in reported cases during a 25-year period to describe changes in the populations most affected by Lyme disease in the United States. We examined demographic characteristics of people with confirmed cases of Lyme disease reported to the Centers for Disease Control and Prevention during 1992-2016 through the National Notifiable Diseases Surveillance System. We grouped cases into 5-year periods (1992-1996, 1997-2001, 2002-2006, 2007-2011, 2012-2016). We calculated the average annual incidence by age and sex and used incidence rate ratios (IRRs) to describe changes in Lyme disease incidence by age and sex over time. We converted patient age at time of illness into patient birth year to ascertain disease patterns according to birth cohorts. The incidence of Lyme disease in the United States doubled from 1992-1996 to 2012-2016 (IRR = 1.74; 95% CI, 1.70-1.78) and increased disproportionately among males; IRRs were 39%-89% higher among males than among females for most age groups. During the study period, children aged 5-9 years were most frequently and consistently affected. In contrast, the average age of adults with Lyme disease increased over time; of all adults, people born during 1950-1964 were the most affected by Lyme disease. Our findings suggest that age-related behaviors and susceptibilities may drive infections among children, and the shifting peak among adults likely reflects a probability proportional to the relative size of the baby boom population. These findings can inform targeted and efficient public health education and intervention efforts.

scholarly journals Basal temperature and thermal sum in phenological phases of nectarine and peach cultivars

2011 ◽  
Vol 46 (12) ◽  
pp. 1588-1596 ◽  
Author(s):  
Adilson Pacheco de Souza ◽  
Sarita Leonel ◽  
Andréa Carvalho da Silva
Keyword(s):  
Degree Days ◽  
Phenological Stages ◽  
Phase Duration ◽  
Open Flower ◽  
Thermal Sum ◽  
Phenological Phases

The objective of this work was to evaluate basal temperature, thermal sum at different phenological stages, phenological phase duration, yield and seasonality of one nectarine and 14 peach cultivars, between 2006 and 2009. The considered phenological phases were: pruning-sprouting; sprouting-flowering, from swollen bud to open flower; flowering-fruiting, from petal fall to medium-sized fruit; and ripening. Minimum basal temperatures (Tb) obtained were: pruning-sprouting, 8°C, irrespective of the cultivars; sprouting-flowering, 10°C, except for 'Cascata 968', which required 8°C Tb; flowering-fruiting, 12°C, except for 'Oro Azteca', which required 14°C Tb; ripening, 14°C, except for 'Sunblaze', 'Diamante Mejorado' and 'Precocinho' with 12°C Tb. For most cultivars, the maximum basal temperatures were 30, 34, 34 and 28ºC for phases pruning-sprouting, sprouting-flowering, flowering-fruiting and ripening, respectively. 'Turmalina', 'Marli' and 'Tropic Beauty' showed average yields of 3,945.0, 3,969.3 and 3,954.0 kg ha-1, respectively, in 2009, while the nectarine 'Sunblaze' showed around 3,900 kg ha-1 in 2008 and 2009. The cultivars differed for their total cycle and for the accumulated thermal sums which varied, respectively, from 245 days and 1,881.4 degree-days for 'Oro Azteca', to144 days and 1,455.7 degree-days for 'Precocinho'.

scholarly journals Meteorological conditions, ozone concentration and leaf age affect gas exchange in Psidium guajava ‛Palumaʼ

Hoehnea ◽  
2017 ◽  
Vol 44 (2) ◽  
pp. 236-245 ◽  
Author(s):  
Juliana Moreno Pina ◽  
Sérgio Tadeu Meirelles ◽  
Regina Maria de Moraes
Keyword(s):  
Gas Exchange ◽  
Ozone Concentration ◽  
Leaf Age ◽  
Psidium Guajava ◽  
Meteorological Conditions ◽  
Gas Exchanges ◽  
Mature Leaves ◽  
Young Leaves ◽  
Entire Experiment ◽  
The City

ABSTRACT This study aimed to investigate the importance of leaf age, meteorological conditions and ozone concentration (O3) on gas exchange of Psidium guajava ‛Paluma'. Saplings were grown and exposed in standard conditions in the city of São Paulo, in six periods of three months with weekly measurements in young and mature leaves. Gas exchanges were higher in young leaves for almost the entire experiment. Mature leaves showed greater reduction in gas exchange. The multivariate analysis of biotic and abiotic variables indicated that vapor pressure deficit (VPD), O3 concentration and radiation were the main variables associated with gas exchange decrease in young leaves. In mature leaves the influence of VPD is lower, but the temperature importance is higher. Moreover, the opposition between assimilation and O3 is more evident in mature leaves, indicating their greater sensitivity to O3.

scholarly journals Distribution and pathogenicity of Pseudomonas cichorii (Swingle) Stapp in coffee in Puerto Rico

1969 ◽  
Vol 87 (3-4) ◽  
pp. 123-135 ◽  
Author(s):  
Luis Sánchez ◽  
Mildred Zapata ◽  
Rocío del P. Rodríguez ◽  
James S. Beaver
Keyword(s):  
Puerto Rico ◽  
Leaf Age ◽  
Coffea Canephora ◽  
Resistance Mechanisms ◽  
Pseudomonas Cichorii ◽  
Inoculation Methods ◽  
Young Leaves ◽  
Resistant Genotypes ◽  
Coffee Species

Seventeen pathogenic strains of Pseudomonas cichorii were isolated from leaf samples of coffee (Coffea arabica) collected from nurseries in eight municipalities of Puerto Rico. Two different inoculation methods were evaluated under in vitro conditions: inoculation of plant-attached old and young leaves grown under greenhouse conditions, and plant-detached young coffee leaves grown under field conditions. Pseudomonas cichorii was more virulent in older leaves, thus indicating that resistance mechanisms differ according to leaf age. Both inoculation methods were reliable in identifying resistant genotypes. Three commercial varieties of coffee (Borbón, Pacas and Caturra) were susceptible to bacterial leaf blight, whereas coffee species Coffea liberica var. Excelsa and Coffea canephora var. Robusta were resistant.

scholarly journals Six-year incidence of visually significant age-related cataract: the Chennai eye disease incidence study

2015 ◽  
Vol 44 (2) ◽  
pp. 114-120 ◽  
Author(s):  
Manish Panday ◽  
Ronnie George ◽  
Rashima Asokan ◽  
Satyamangalam Ve Ramesh ◽  
Lokapavani Velumuri ◽  
...  
Keyword(s):  
Incidence Study ◽  
Disease Incidence ◽  
Eye Disease ◽  
Age Related

Photosynthetic response of geranium to elevated CO2 as affected by leaf age and time of CO2 exposure

1991 ◽  
Vol 69 (11) ◽  
pp. 2482-2488 ◽  
Author(s):  
D. W. Kelly ◽  
P. R. Hicklenton ◽  
E. G. Reekie
Keyword(s):  
Stomatal Density ◽  
Leaf Age ◽  
Net Photosynthesis ◽  
Leaf Thickness ◽  
Middle Aged ◽  
Future Studies ◽  
Structural Modifications ◽  
Young Leaves ◽  
Developmental Characteristics ◽  
Density Results

Geranium plants were grown from seed in chambers maintained at 350 or 1000 μL∙L−1 CO2. Phtopsynthesis as affected by leaf age and by leaf position was determined. Elevated CO2 enhanced photosynthesis to the greatest extent in middle-aged leaves; very young leaves exhibited little enhancement, and net photosynthesis in the oldest leaves was depressed by elevated CO2. Temporary increases in net photosynthesis (relative to leaves developed at high CO2) resulted when young leaves grown at 350 μL∙L−1 CO2 were switched to 1000 μL∙L−1 CO2. Leaves switched later in development exhibited permanent enhancement. Middle-aged leaves exhibited a temporary depression followed by permanent enhancement. Leaves developed at high CO2 and switched to low CO2 did not exhibit any photosynthetic depression relative to plants grown continuously at low CO2. Similarly, leaves developed at low CO2, switched to high CO2 for various lengths of time, and returned to low CO2 showed no photosynthetic depression. Leaves developed at low CO2 and switched to high CO2 exhibited increases in specific leaf weight and leaf thickness. The increase in leaf thickness was proportional to length of time spent at high CO2. High CO2 depressed the rate at which stomata developed but did not affect final stomatal density. Results suggest that photosynthesis at low CO2 was limited by CO2 regardless of developmental environment, whereas photosynthesis at high CO2 was limited by the developmental characteristics of the leaf. Further, both biochemical and structural modifications appear to be involved in this response. Because of the very different responses of young versus old leaves, future studies should be careful to consider leaf age in assessing response to elevated CO2. Key words: carbon dioxide, elevated CO2, photosynthesis, geranium.

scholarly journals Differential responses between mature and young leaves of sunflower plants to oxidative stress caused by water deficit

2010 ◽  
Vol 40 (6) ◽  
pp. 1290-1294 ◽  
Author(s):  
Inês Cechin ◽  
Natália Corniani ◽  
Terezinha de Fátima Fumis ◽  
Ana Catarina Cataneo
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Intercellular Co2 Concentration ◽  
Leaf Age ◽  
Co2 Concentration ◽  
Mature Leaves ◽  
Young Leaves ◽  
Mda Content ◽  
Gas Exchange Characteristics

The effects of water stress and rehydration on leaf gas exchange characteristics along with changes in lipid peroxidation and pirogalol peroxidase (PG-POD) were studied in mature and in young leaves of sunflower (Helianthus annuus L.), which were grown in a greenhouse. Water stress reduced photosynthesis (Pn), stomatal conductance (g s), and transpiration (E) in both young and mature leaves. However, the amplitude of the reduction was dependent on leaf age. The intercellular CO2 concentration (Ci) was increased in mature leaves but it was not altered in young leaves. Instantaneous water use efficiency (WUE) in mature stressed leaves was reduced when compared to control leaves while in young stressed leaves it was maintained to the same level as the control. After 24h of rehydration, most of the parameters related to gas exchange recovered to the same level as the unstressed plants except gs and E in mature leaves. Water stress did not activated PG-POD independently of leaf age. However, after rehydration the enzyme activity was increased in mature leaves and remained to the same as the control in young leaves. Malondialdehyde (MDA) content was increased by water stress in both mature and young leaves. The results suggest that young leaves are more susceptible to water stress in terms of gas exchange characteristics than mature leaves although both went through oxidative estresse.

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