scholarly journals Ramularia leaf spot and Boll rot are affected differently by organic and inorganic nitrogen fertilization in cotton plants

2021 ◽  
Author(s):  
Oscar Palma-Zambrano ◽  
Freddy Zambrano-Gavilanes ◽  
Diego Portalanza ◽  
Felipe R. Rafael Garcés Fiallos
Keyword(s):  
Nitrogen Fertilization ◽  
Leaf Spot ◽  
Logistic Model ◽  
Poultry Manure ◽  
Factor B ◽  
Seed Cake ◽  
Ramularia Leaf Spot ◽  
Cotton Plants ◽  
Boll Rot ◽  
Epidemiological Parameters

Abstract Background: In this work, the interaction among nitrogen fertilization using bovine manure, poultry manure, Jatropha curcas seed cake and urea, and the diseases Ramularia leaf spot (RLS) and Boll rot (BR), caused by Ramulariopsis pseudoglycines and Diplodia gossypina, respectively, on cotton plants (Gossypium hirsutum L.), was studied under field conditions. The intensity (incidence and severity in percentage) of RLS and the incidence (%) of BR were evaluated six times, starting in the reproductive stage B1 (first visible flower bud). A randomized complete block experimental design with a 4x4 factorial arrangement (fertilizers x dose), totaling 16 treatments were used. The disease progress was analyzed with the nonlinear Logistic and Gomperts models, obtaining the initial disease's epidemiological parameters (Y0) and progress rate (r). Results: Cotton plants fertilized with 100 kg N ha-1 of J. curcas seed cake and poultry manure with 100 and 200 kg N ha-1 showed an incidence between 16 and 21% of RLS. In contrast, plants fertilized with bovine manure presented the highest incidence of ramularia leaf spot (33%). Regarding factor B (dose), cotton plants fertilized with 50 kg N ha-1, showed a higher percentage of BR incidence, being different from those fertilized with the other doses. In the analysis of the interaction corresponding to the BR incidence, no response pattern was found in the doses for each fertilizer. No correlation was observed between the three health variables analyzed, finding probabilities between 0.002 and 0.892. In the temporal progress of RLS incidence, it was shown that fertilization with J. curcas seedcake and poultry manure was lower than the rest. In severity, the plants were fertilized by J. curcas seedcake concerning the rest. The progression curve of RLS severity temporarily increased similarly, observing that plants fertilized with higher doses reached a lower final proportion of the disease.Regarding the modeling of epidemics using the nonlinear Logistic and Gompertz models, the first model better represented the RLS, except for factor B, where none of the curves was significant. In the Logistic model, a lower amount of initial disease was found (Y0) of RLS, both in incidence (0.259) as in severity (0.081), in plants fertilized with J. curcas seed cake and poultry manure, compared to the rest. For the case of BR incidence, none of the nonlinear models used could be represented.Conclusions: Plants fertilized with 50 kg N ha-1, presented an incidence twice higher than those obtained with other fertilizers. The Logistic model better fits RLS, but no model was adapted to BR. Only the RLS epidemiological parameters were affected differently in this experiment compared to BR disease.

Ramularia leaf spot: an emergent disease of cotton in Brazil

2019 ◽  
Vol 44 (6) ◽  
pp. 473-482 ◽  
Author(s):  
Juliano Cesar da Silva ◽  
Wagner Bettiol ◽  
Nelson Dias Suassuna
Keyword(s):  
Leaf Spot ◽  
Ramularia Leaf Spot

scholarly journals A trade off between mlo resistance to powdery mildew and increased susceptibility of barley to a newly important disease, Ramularia leaf spot

2014 ◽  
Vol 65 (4) ◽  
pp. 1025-1037 ◽  
Author(s):  
Graham R. D. McGrann ◽  
Anna Stavrinides ◽  
Joanne Russell ◽  
Margaret M. Corbitt ◽  
Allan Booth ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Leaf Spot ◽  
Trade Off ◽  
Ramularia Leaf Spot ◽  
Important Disease ◽  
Increased Susceptibility

scholarly journals Nitrogen and Flowering Dogwood. I. Impact of Nitrogen Fertilization Rate on the Occurrence of Spot Anthracnose, Powdery Mildew, and Cercospora Leaf Spot and Their Effect on Tree Growth

2008 ◽  
Vol 26 (4) ◽  
pp. 197-203
Author(s):  
A.K. Hagan ◽  
J.R. Akridge ◽  
K.L. Bowen
Keyword(s):  
Powdery Mildew ◽  
Nitrogen Fertilization ◽  
Leaf Spot ◽  
Tree Height ◽  
Fertilization Rate ◽  
Spot Intensity ◽  
Cercospora Leaf Spot ◽  
Trunk Diameter ◽  
Flowering Dogwood ◽  
N Rates

Abstract Impact of nitrogen (N) rate on spot anthracnose, powdery mildew, and Cercospora leaf spot as well as their impact on the growth of field-grown ‘Cloud 9’ and ‘Cherokee Chief’ flowering dogwood was assessed in 2003, 2004, and 2005. From 2001 to 2005, ammonium nitrate was applied at 4.1, 8.3, 16.5, 33.0 and 66.0 g N·m−2 (37.5, 75, 150, 300, 600 lb N·A−1). Heritage 50W fungicide was applied to one ‘Cherokee Chief’ and ‘Cloud 9’ flowering dogwood in each plot, while the second was untreated. Powdery mildew and Cercospora leaf spot were impacted by N rate more than spot anthracnose. In two of three years, powdery mildew intensified, particularly on the non-treated trees, as N rates increased. Cercospora leaf spot intensity (AUDPCI) and defoliation (AUDPCD) on the fungicide-treated and non-treated trees was influenced by N-rate in two of three and one of three years, respectively. Regardless of fungicide treatment, Cercospora leaf spot incited leaf spotting and defoliation was often lower at the two highest than the two lowest N rates. A reduction in the bract and leaf spot phases of spot anthracnose at the highest N rate was noted in 2004. While spot anthracnose was negatively correlated with trunk diameter in all three years and tree height in 2003 and 2004, Cercospora leaf spot intensity and defoliation were negatively correlated with tree height and trunk diameter in all three and two of three years, respectively. Powdery mildew had no impact on tree height or trunk diameter. Heritage 50W not only controlled spot anthracnose and powdery mildew but also slowed Cercospora leaf spot development sufficiently to enhance leaf retention and fall color.

Ramularia leaf spot in barley

2021 ◽  
pp. 681-706
Author(s):  
Neil Havis ◽  
Keyword(s):  
Life Cycle ◽  
Leaf Spot ◽  
Fungicide Resistance ◽  
Complex Life Cycle ◽  
Rate Of Development ◽  
Major Disease ◽  
Ramularia Leaf Spot ◽  
The World ◽  
Causal Pathogen ◽  
And Control

Ramularia leaf spot is an emerging pathogen across barley growing regions of the world. It's rise from minor to major disease has been rapid over the last twenty years. The causal pathogen, Ramularia collo-cygni is poorly understood but it has been shown to have a complex life cycle and the ability to exist on many hosts in an endophytic state. The rate of development of fungicide resistance in the fungus is also extremely fast and many of the major single site fungicides are no longer effective in many countries. With multisite fungicides having their approval or reconsidered and no consistent varietal resistance available, control of the disease is increasing challenging. This chapter reviews the latest research into Ramularia biology and control and highlights the areas where recent advances have been made.

scholarly journals The effect of nitrogen fertilization on the incidence of olive fruit fly, olive leaf spot and olive anthracnose in two olive cultivars grown in rainfed conditions

2019 ◽  
Vol 256 ◽  
pp. 108658
Author(s):  
M. Ângelo Rodrigues ◽  
Valentim Coelho ◽  
Margarida Arrobas ◽  
Eugénia Gouveia ◽  
Soraia Raimundo ◽  
...  
Keyword(s):  
Nitrogen Fertilization ◽  
Leaf Spot ◽  
Fruit Fly ◽  
Olive Fruit Fly ◽  
Olive Leaf ◽  
Olive Fruit ◽  
Rainfed Conditions ◽  
Olive Cultivars

scholarly journals First Report of Ramularia Leaf Spot Caused by Ramularia collo-cygni on Leaves and Seeds of Barley in Estonia

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 997-997 ◽  
Author(s):  
P. Sooväli ◽  
M. Tikhonova ◽  
P. Matušinsky
Keyword(s):  
Leaf Spot ◽  
Growth Stage ◽  
Positive Control ◽  
Pathogenicity Test ◽  
Koch’S Postulates ◽  
Ramularia Leaf Spot ◽  
Initial Symptoms ◽  
Two Samples ◽  
Agricultural Regions ◽  
Koch's Postulates

Ramularia leaf spot (RLS) is a disease of barley (Hordeum vulgare) caused by the fungus Ramularia collo-cygni Sutton & Waller (Rcc). Rcc causes necrotic lesions, premature senescence of leaves, and yield reduction. Under Estonian conditions, there are usually no leaf spots on the upper leaves of barley prior to flowering. In 2009, 2010, and 2012, symptoms similar to those of RLS were observed on leaves of spring and winter barley in several Estonian agricultural regions. Approximately 30% of the plants in affected fields were symptomatic. Symptoms were not observed in 2011, which was a dry and hot year. Initial symptoms were small brown spots, beginning on the upper leaves (flag leaf, F-1 leaf) at the flowering growth stage (4). Later, the spots spread to the sheaths, stems, and awns and became necrotic. The lateral margins of the spots were delimited by the leaf veins and spots are surrounded by a chlorotic halo. During summer 2012, two samples of 15 F-1 leaves were collected from spring barley cv. Maali and line SJ111609 from the Estonian Crop Research Institute in eastern Estonia in late July at growth stage 71 (4). In addition, six grain samples, containing 200 seeds each of the cv. Maali, were collected from different agricultural regions in Estonia, along with one grain sample of SJ111609 from Jõgeva. All samples were collected from untreated plots and leaves were observed under a dissecting microscope, revealing white clusters of conidiophores in rows on the undersides of the leaves. Conidia and conidiophores were scraped aseptically from the leaf surface using a sterile needle under a dissecting microscope and transferred to potato dextrose agar (PDA) containing ampicillin sodium salt (50 mg l−1). Plates were incubated at 18°C in the dark for 20 days until fungal mycelia were produced. The fungus was initially identified as Rcc on the basis of morphological characteristics (3). Colorless, 0- to 3-septate conidiophores were 15 to 17 × 2 to 5 μm, with a strongly curved end. Conidia were 7 to 11 × 3 to 6 μm, solitary, subglobose, single-celled, and of a darkish color. To confirm the presence of Rcc, DNA was extracted from the original barley leaf material, milled seeds, and positive control mycelia of Rcc grown on PDA using DNeasy Plant Mini Kit (Qiagen Gmbh, D-40724 Hilden, Germany) following manufacturer's guides. Rcc specific primers RC3 and RC5 (1) were used. A positive control consisting of 1 ng of purified Rcc DNA was included in the PCR. Standard PCR was conducted in a SEE AMP Seegene cycler. PCR were carried out in 20 μl volumes, containing 2 μl of DNA, 10 μl PCR mix, 0.4 μl each of forward and reverse Rcc primers, and 7.2 μl H2O. Qualitative detection analyzed by standard PCR with primers RC3 and RC5 revealed the presence of Rcc in symptomatic leaves and seeds. To complete Koch's postulates, a pathogenicity test was performed. Twenty-five barley seedlings were grown under controlled conditions (15°C/48 h dark, 16 h light/8 h dark, 70% RH) and spray-inoculated with a suspension of Rcc mycelium fragments as described by Macepeace et al. (2). The pathogen was re-isolated from leaves with necrotic lesions similar to those observed in the field, thus fulfilling Koch's postulates. To our knowledge, this is the first confirmed report of Ramularia leaf spot caused by Ramularia collo-cygni on barley in Estonia. References: (1) P. Frei et al. J. Phytopathol. 155:281, 2007. (2) J. C. Makepeace et al. Plant Pathol. 57:991, 2008. (3) B. C. Sutton and J. M. Waller. Trans. Brit. Mycol. Soc. 90:55, 1988. (4) J. C. Zadoks et al. Weed Res. 14:415, 1974.

scholarly journals SEVERITY OF RAMULARIA LEAF SPOT AND SEED COTTON YIELD IN DIFFERENT SOWING TIMES

2016 ◽  
Vol 29 (3) ◽  
pp. 603-610 ◽  
Author(s):  
JOÃO PAULO ASCARI ◽  
DEJÂNIA VIEIRA DE ARAÚJO ◽  
LEONARDO DIOGO EHLE DIAS ◽  
GIOVANI JUNIOR BAGATINI ◽  
INÊS ROEDER NOGUEIRA MENDES
Keyword(s):  
Disease Control ◽  
Leaf Spot ◽  
Cotton Yield ◽  
Yield Losses ◽  
Seed Cotton ◽  
Sowing Time ◽  
Fungicide Application ◽  
Progress Curve ◽  
Ramularia Leaf Spot ◽  
Diagrammatic Scale

ABSTRACT The ramularia leaf spot (RLS) disease causes cotton yield losses. Choosing a less susceptible cultivar and a sowing time that are less favorable to the pathogen contribute to the management of this disease. The objective of this work was to evaluate the severity of ramularia leaf spot on cotton cultivars sowed in two different times. The experiment was conducted in a triple factorial design (4x3x2), consisted of four cultivars, the three thirds of the plant and two sowing times, with four replications. Each plot was divided in two twin plots, one with fungicide application (with disease control) and the other without fungicide application (without disease control). The severity assessments were performed every seven days, considering each third of the plant with a diagrammatic scale. Yield was evaluated in each plot. There was a significant interaction between sowing times and the thirds of the plant in the plots without disease control for RLS severity, with the highest values of area under the disease progress curve (AUDPC) in the first sowing time (ST1) and in the lower third of the plant. The FMT705 cultivar had the highest and FM951LL the lowest value of AUDPC. The AUDPC of these cultivars were no statistically different in the second sowing time (ST2), but they had higher AUDPC values in the lower third. Highest yields were found with ST1 in plots with disease control, with no differences between the cultivars, however, lower yields were found in plots without disease control.

Directional Spread of Septoria Leaf Spot in Tomato Rows

Plant Disease ◽  
1997 ◽  
Vol 81 (3) ◽  
pp. 272-276 ◽  
Author(s):  
S. K. Parker ◽  
F. W. Nutter ◽  
M. L. Gleason
Keyword(s):  
Disease Severity ◽  
Leaf Spot ◽  
Logistic Model ◽  
Disease Spread ◽  
Infection Rates ◽  
Fresh Market ◽  
Tomato Plants ◽  
Septoria Leaf Spot

Disease severity of Septoria leaf spot in rows of fresh-market tomato plants that were not staked was assessed in 1992 and 1993 following inoculation of the center plant in each row. Both temporal disease increase and spatial disease gradients were best described by the logistic model. Apparent infection rates for Septoria leaf spot epidemics averaged 0.282 day-1 (SE = 0.015, r2 = 0.96, P < 0.0001) in 1992 and 0.260 day-1 (SE = 0.011, r2 = 0.96, P < 0.0001) in 1993. Apparent infection rates remained relatively constant at increasing distances from initial foci. Estimated values for disease gradient slopes 3 to 5 weeks after inoculation ranged from -0.26 to -1.05 m-1. Velocities of disease spread ranged from 0.3 to 1.3 m/day. Results of analysis of disease severity data for these 2 years suggest that Septoria leaf spot epidemics can develop at rapid rates, but steep disease gradients limit the velocity of spread.

Sign in / Sign up

Export Citation Format

Share Document