Pseudomonas cichorii (bacterial blight of endive).

2021 ◽  
Author(s):  
Ebrahim Osdaghi
Keyword(s):  
Environmental Conditions ◽  
Leaf Spot ◽  
Bacterial Blight ◽  
Severe Disease ◽  
Disease Outbreaks ◽  
Severe Damage ◽  
Pseudomonas Cichorii

Abstract Under environmental conditions favourable to the pathogen, diseases incited by P. cichorii cause severe damage to the host and can result in outbreaks. Outbreaks in the nursery or in the field during warm winters in Florida, USA, can lead to widespread disease affecting thousands of plants (Jones et al., 1983; Chase and Brunk, 1984; Uddin and McCarter, 1996). Diseases caused by P. cichorii can appear sporadically over a number of years then cause severe outbreaks such as the outbreak of 'varnish spot of lettuce' in California (Grogan et al. 1977) and 'brown stem of celery' in Florida, USA (Pernezny et al., 1994). Severe disease outbreaks on lettuce leading to losses of up to 100% have been reported in California (Grogan et al., 1977), Italy (Bazzi and Mazzucchi, 1979) and Portugal (Ferreira-Pinto and Oliveira, 1993). In Italy and France, P. cichorii is a recurring problem on endive and lettuce (Allex and Rat 1990; D'Ascenzo et al., 1997). In Florida, brown stem of chrysanthemum only occurs about every 5 to 6 years whereas leaf spot occurs annually (Pernezny et al., 1994).

scholarly journals Pseudomonas cichorii (bacterial blight of endive).

2021 ◽  
Author(s):  
Ebrahim Osdaghi
Keyword(s):  
Environmental Conditions ◽  
Leaf Spot ◽  
Bacterial Blight ◽  
Severe Disease ◽  
Disease Outbreaks ◽  
Severe Damage ◽  
Pseudomonas Cichorii

Abstract Under environmental conditions favourable to the pathogen, diseases incited by P. cichorii cause severe damage to the host and can result in outbreaks. Outbreaks in the nursery or in the field during warm winters in Florida, USA, can lead to widespread disease affecting thousands of plants (Jones et al., 1983; Chase and Brunk, 1984; Uddin and McCarter, 1996). Diseases caused by P. cichorii can appear sporadically over a number of years then cause severe outbreaks such as the outbreak of 'varnish spot of lettuce' in California (Grogan et al. 1977) and 'brown stem of celery' in Florida, USA (Pernezny et al., 1994). Severe disease outbreaks on lettuce leading to losses of up to 100% have been reported in California (Grogan et al., 1977), Italy (Bazzi and Mazzucchi, 1979) and Portugal (Ferreira-Pinto and Oliveira, 1993). In Italy and France, P. cichorii is a recurring problem on endive and lettuce (Allex and Rat 1990; D'Ascenzo et al., 1997). In Florida, brown stem of chrysanthemum only occurs about every 5 to 6 years whereas leaf spot occurs annually (Pernezny et al., 1994).

scholarly journals Epidemiology and management of bacterial leaf spot on watermelon caused byPseudomonas syringae

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1222-1229 ◽  
Author(s):  
E. A. Newberry ◽  
L. Ritchie ◽  
B. Babu ◽  
T. Sanchez ◽  
K. A. Beckham ◽  
...  
Keyword(s):  
Disease Severity ◽  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Negative Relationship ◽  
Disease Outbreaks ◽  
Field Trials ◽  
Multiple Regression Model ◽  
Bacterial Leaf Spot ◽  
Progress Curve ◽  
Cool Conditions

Bacterial leaf spot of watermelon caused by Pseudomonas syringae has been an emerging disease in the southeastern United States in recent years. Disease outbreaks in Florida were widespread from 2013 to 2014 and resulted in foliar blighting at the early stages of the crop and transplant losses. We conducted a series of field trials at two locations over the course of two years to examine the chemical control options that may be effective in management of this disease, and to investigate the environmental conditions conducive for bacterial leaf spot development. Weekly applications of acibenzolar-S-methyl (ASM) foliar, ASM drip, or copper hydroxide mixed with ethylene bis-dithiocarbamate were effective in reducing the standardized area under the disease progress curve (P < 0.05). Pearson’s correlation test demonstrated a negative relationship between the average weekly temperature and disease severity (–0.77, P = 0.0002). When incorporated into a multiple regression model with the square root transformed average weekly rainfall, these two variables accounted for 71% of the variability observed in the weekly disease severity (P < 0.0001). This information should be considered when choosing the planting date for watermelon seedlings as the cool conditions often encountered early in the spring season are conducive for bacterial leaf spot development.

scholarly journals Identification and pathogenicity of Pseudomonas cichorii associated with a bacterial blight of gerbera in the Federal District

2016 ◽  
Vol 34 (2) ◽  
pp. 244-248 ◽  
Author(s):  
Eder Marques ◽  
Rafaela CF Borges ◽  
Carlos H Uesugi
Keyword(s):  
Bacterial Blight ◽  
Federal District ◽  
Cut Flower ◽  
16S Rdna Gene ◽  
Pseudomonas Cichorii ◽  
Partial Sequencing ◽  
Fluorescent Pigment ◽  
High Tunnels ◽  
Pathogenicity Tests ◽  
Distrito Federal

ABSTRACT: In 2013, leaf samples of gerbera plants showing symptoms of bacterial blight were collected in cut-flower high tunnels, in the settlement of núcleo rural alexandre gusmão, located in brazlândia, distrito federal, brazil. seven isolates obtained were subjected to phenotypic and molecular characterization, including pathogenicity tests, lopat, and partial sequencing of the 16s rdna gene. all isolates were gram-negative, aerobic, oxidase-positive, produced fluorescent pigment, induced hypersensitivity in tobacco leaves, used sorbitol and glutamate and were pathogenic to 24 different plant species. results of these tests and analysis of the sequences of rdna showed 100% identity with pseudomonas cichorii. to our knowledge, this is the first report of p. cichorii in gerbera in the federal district.

Quantifying the Effects of Fungicides and Tillage on Cercospora sojina Severity and Yield of Soybean

2018 ◽  
Vol 19 (3) ◽  
pp. 226-232
Author(s):  
Alemu Mengistu ◽  
Heather M. Kelly ◽  
Prakash R. Arelli ◽  
Nacer Bellaloui ◽  
Binbin Lin
Keyword(s):  
Disease Severity ◽  
Environmental Conditions ◽  
Leaf Spot ◽  
Cercospora Sojina ◽  
University Of Tennessee ◽  
No Till ◽  
Untreated Check ◽  
Severity Of The Disease ◽  
Research And Education ◽  
The University

A field study was conducted in 2014 through 2016 at the University of Tennessee Research and Education Center, Milan, TN, to determine fungicide effects on frogeye leaf spot (FLS) caused by Cercospora sojina and to determine disease severity and yield under no-till and tillage. Each plot was visually rated for FLS severity based on the percent leaf area covered from 0 to 100%. The result showed that tillage did not affect severity of the disease or yield. However, there were significant effects from fungicide, year-to-year effects, and fungicide × year interactions. Among the three years, disease severity in 2016 was greater than in 2014 and 2015. Among the six fungicides, Topsin, Topguard, Quadris TOP SBX, and Priaxor significantly (P ≤ 0.05) reduced maximum disease severity in 2016. All fungicide applications improved yield relative to the untreated check. Topsin and Quadris TOP SBX, however, had consistently the highest percent yield increases. These results suggest that not all fungicides that reduced FLS severity equally protected yield, indicating that yield and environmental conditions need to be considered when making appropriate fungicide recommendations in tilled and no-till systems.

Relative host resistance to Alternaria leaf spot in canola and mustard varieties is defined by Alternaria species

2020 ◽  
Vol 71 (7) ◽  
pp. 689
Author(s):  
Hebba F. D. Al-Lami ◽  
Ming Pei You ◽  
Martin J. Barbetti
Keyword(s):  
Host Resistance ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Severe Disease ◽  
Indian Mustard ◽  
Moderate Level ◽  
Alternaria Leaf Spot ◽  
Ethiopian Mustard ◽  
Alternaria Species ◽  
Collapse Index

Both Alternaria japonica and A. brassicae cause severe Alternaria leaf spot on canola (Brassica napus) and mustard (B. juncea). We tested 103 Brassicaceae varieties including 93 Australian canola, nine Indian mustard, and a single variety of Ethiopian mustard (B. carinata) under greenhouse conditions to identify host resistance to Alternaria leaf spot caused by A. japonica and A. brassicae in terms of disease incidence (percentage leaf disease incidence, %LDI), disease severity (percentage leaf area diseased, %LAD) and defoliation (percentage leaf collapse index, %LCI). Against A. japonica, across the three parameters, B. napus Surpass 404 CL was the most resistant (%LDI 7.5, %LAD 5.0, %LCI 0). Varieties Hyola 635 CC, Oscar, AG-Outback and Rottnest, with %LDI 15.6–19.4 and %LAD 12.5–15.6, also showed strong resistance, and with %LCI 10. Varieties 47C02, ATR-Signal and Clancy of B. napus showed a moderate level of resistance across %LDI (21.2–25.6) and %LAD (15.0–20.6), along with a low level of defoliation (%LCI 10). Varieties 46C03, 46C72, ATR-Cobbler and Granite TT of B. napus also showed a moderate level of resistance, with %LDI 23.1–28.7, %LAD 18.1–20.6 and %LCI 11.2–14.4. The significance of this resistance against A. japonica is highlighted by the severe disease on B. napus Thunder TT (%LDI 78.8, %LAD 72.5, %LCI 47.5). Against A. brassicae, all varieties showed susceptibility; however, B. napus ATR-Grace was the least susceptible in relation to disease incidence (%LDI 41.2) and severity (%LAD 36.2), and B. napus Hyola 450 TT the most susceptible (%LDI 90.0, %LAD 82.5). Variety Hurricane of B. napus was the least susceptible in terms of consequent defoliation (%LCI 11.2) and B. napus CBTM Tribune the most susceptible (%LCI 81.2). The B. carinata variety BCA 1 (ATC 95065) and all test B. juncea varieties showed susceptibility to both pathogens. These findings demonstrate high levels of resistance across Australian canola varieties against A. japonica that can be directly deployed where A. japonica is important and can be utilised by breeders for improving resistance in future varieties. By contrast, susceptibility across Australian canola and mustard varieties to A. brassicae is concerning, highlighting a need to locate suitable resistances and, until effective host resistance can be located, to develop and deploy cultural and chemical options.

scholarly journals Verticillium Wilt in Oilseed Rape—the Microbiome is Crucial for Disease Outbreaks as Well as for Efficient Suppression

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 866 ◽  
Author(s):  
Daria Rybakova ◽  
Mariann Wikström ◽  
Fia Birch-Jensen ◽  
Joeke Postma ◽  
Ralf Udo Ehlers ◽  
...  
Keyword(s):  
Verticillium Wilt ◽  
Severe Disease ◽  
Disease Outbreaks ◽  
Field Trials ◽  
Growth Conditions ◽  
Assessment Method ◽  
Serratia Plymuthica ◽  
Hierarchical Selection

Microbiome management is a promising way to suppress verticillium wilt, a severe disease in Brassica caused by Verticillium longisporum. In order to improve current biocontrol strategies, we compared bacterial Verticillium antagonists in different assays using a hierarchical selection and evaluation scheme, and we integrated outcomes of our previous studies. The result was strongly dependent on the assessment method chosen (in vitro, in vivo, in situ), on the growth conditions of the plants and their genotype. The most promising biocontrol candidate identified was a Brassica endophyte Serratia plymuthica F20. Positive results were confirmed in field trials and by microscopically visualizing the three-way interaction. Applying antagonists in seed treatment contributes to an exceptionally low ecological footprint, supporting efficient economic and ecological solutions to controlling verticillium wilt. Indigenous microbiome, especially soil and seed microbiome, has been identified as key to understanding disease outbreaks and suppression. We suggest that verticillium wilt is a microbiome-driven disease caused by a reduction in microbial diversity within seeds and in the soil surrounding them. We strongly recommend integrating microbiome data in the development of new biocontrol and breeding strategies and combining both strategies with the aim of designing healthy microbiomes, thus making plants more resilient toward soil-borne pathogens.

scholarly journals Effective Biomass Reduction of the Invasive Weed Species Banana Poka by Septoria Leaf Spot

Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Eduardo E. Trujillo ◽  
Chris Kadooka ◽  
Victor Tanimoto ◽  
Steve Bergfeld ◽  
Glenn Shishido ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Severe Disease ◽  
Disease Spread ◽  
Leaf Spot Disease ◽  
Native Forest ◽  
Invasive Weed ◽  
Disease Epidemics ◽  
Biomass Reduction ◽  
Septoria Leaf Spot

Inoculations of Septoria passiflorae for biological control of banana poka (Passiflora tripartita var. tripartita) at different forest sites in Hawaii, Kauai, and Maui resulted in successful establishment of the Septoria leaf spot disease at all sites during 1996. Semi-annual monitoring of sites in 1997 revealed low disease incidence and no disease spread to adjacent non-inoculated plants. Site inspections in March 1998 revealed light disease epidemics causing visible defoliation at inoculated sites on Kauai and Maui. Banana poka biomass reduction at sites with light epidemics of the disease in Kauai and Maui were estimated to be less than 10% in 1998, whereas in 1999 biomass reduction ranged from 50 to 95%. Five of 11 inoculation sites in 1996 on the island of Hawaii showed no disease. These five sites on Kaloko had frequent acid rainfall averaging 3.2 pH, which inhibited spore germination and infection. Six sites, free of acid rain, three at Hilo Forest Reserve and three at Puuwaawaa Wildlife Sanctuary, had severe disease epidemics by 1998, and vine defoliation was >90%. Widespread epidemics of the disease occurred in 1999, resulting in estimated 80 to 95% biomass reductions in more than 2,000 hectares of native forest infested with banana poka.

scholarly journals A Risk Assessment Model for Bacterial Leaf Spot of Pepper (Capsicum annuum), Caused by Xanthomonas euvesicatoria, Based on Concentrations of Macronutrients, Micronutrients, and Micronutrient Ratios

2017 ◽  
Vol 107 (11) ◽  
pp. 1331-1338
Author(s):  
B. Dutta ◽  
D. B. Langston ◽  
X. Luo ◽  
S. Carlson ◽  
J. Kichler ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Leaf Spot ◽  
Management Strategy ◽  
Integrated Management ◽  
Assessment Model ◽  
Bacterial Leaf Spot ◽  
Phytopathogenic Bacterium ◽  
Pathogenesis Related ◽  
Xanthomonas Euvesicatoria ◽  
Predicted Values

The phytopathogenic bacterium Xanthomonas euvesicatoria causes bacterial leaf spot (BLS) of pepper and has a worldwide distribution. BLS is difficult to control and an integrated management strategy that incorporates crop rotation, use of clean seed and clean plants, weed control, resistant varieties, applications of bactericides, biocontrol agents, and systemic acquired resistance (SAR) inducers is generally recommended. However, even with that arsenal of weapons, BLS can still be responsible for severe losses under favorable environmental conditions. Thus, additional tools need to be added to an overall integrated management strategy to combat BLS. In this article, we developed several models from 2012 to 2014 that were based on how macronutrients, micronutrients, and micronutrient ratios affect BLS severity. Factors used to select a model for validation included highly significant P values, high adjusted R2 values, low variance inflation factor values (<5), root mean square error, Mallow’s Cp, and high Akaike’s information criterion correction values. In addition, salicylic acid (SA) concentrations and relative expression of nonexpresser pathogenesis-related gene1 (NPR1) and pathogenesis-related protein 1 (PR1) in pepper tissues were also considered in model selection. A model (ECGA1) consisting of concentrations of copper, manganese, potassium, and the iron/zinc ratio as independent variables was used for validation in three different commercial pepper fields in Georgia: Colquitt County and Worth County in 2015 and Tift County in 2016. When area under the disease progress curve (AUDPC) values for two field sites (Colquitt and Worth Counties) in 2015 were pulled together and plotted against ECGA1-predicted values for both sites, the resulting relationship was highly significant (P = 0.0001) with an R2 value of 0.92. A significant relationship between observed AUDPC versus predicted values was also observed in Tift County in 2016 (P < 0.001; adjusted R2 = 0.98). Relative gene expression of both NPR1 and PR1 genes was significantly (P < 0.01) higher in pepper grown in predicted low-risk sites compared with pepper from high-risk sites in Colquitt, Worth, and Tift Counties. Although BLS severity will fluctuate depending on environmental conditions, the data indicate that the level of risk at a particular location may be influenced by how macronutrient and micronutrient concentrations affect plant disease resistance genes in the SAR pathway.

scholarly journals Mejoramiento genético para tolerancia a altas temperaturas y resistencia a mosaico dorado en frijol común.

2006 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Juan Carlos Rosas ◽  
Aracely Castro ◽  
James S. Beaver ◽  
Carlos A. Pérez ◽  
Adrián Morales ◽  
...  
Keyword(s):  
Costa Rica ◽  
El Salvador ◽  
Heat Tolerance ◽  
Leaf Spot ◽  
Bacterial Blight ◽  
Angular Leaf Spot ◽  
Irrigation District ◽  
Agronomic Performance ◽  
Common Bacterial Blight ◽  
Commercial Value

In 1994-95, sources of heat tolerance were identified in common beans after screened several germplasm and advanced lines nurseries in Choluteca and Nacaome (≤ 50 masl), in the southern region of Honduras. The best heat tolerant genotypes were validated under greenhouse controlled conditions (35/27 °C day/night) in Geneva, New York. Afterward, crosses were made to develop small-red bean lines with heat tolerance and resistance to BGMV and other limiting factors. The F2- F5 segregant populations were evaluated for multiple traits including BGMV, common bacterial blight, angular leaf spot, rust, low fertility conditions, and selected for agronomic performance and commercial value. In 1998, 217 F6 and F7 advanced lines were evaluated in the irrigation district Lempa-Acahuapa (20 masl), in the Pacific region of El Salvador for heat tolerance and BGMV. The same nurseries were evaluated in Liberia, in the Northwest region of Costa Rica, for tolerance to high temperatures; and at Zamorano, Honduras for resistance to common bacterial blight, angular leaf spot and rust. A group of lines were identified having superior yield and adaptation than commercial checks, under high temperature conditions in El Salvador and Costa Rica. Some of these lines were also resistant to BGMV in El Salvador, and moderate resistant to web blight in Costa Rica, and they had excellent agronomic performance and good commercial value.

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