scholarly journals Difference between isolates from brown eye spot and black spot lesions in coffee plants

2019 ◽  
Vol 54 ◽  
Author(s):  
Deila Magna dos Santos Botelho ◽  
Mário Lucio Vilela de Resende ◽  
Juliana Costa de Rezende ◽  
Pedro Martins Ribeiro Júnior ◽  
Camila Cristina Lage de Andrade ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Mycelial Growth ◽  
Black Spot ◽  
Infection Process ◽  
The State ◽  
Cercospora Leaf Spot ◽  
Conidial Morphology ◽  
Coffee Plants ◽  
The Difference ◽  
Brown Eye Spot

Abstract: The objective of this work was to evaluate the difference between the isolates from two cercospora leaf spot symptoms (brown eye spot and black spot) in relation to conidial morphology, mycelial growth, cercosporin production, and reproduction of symptoms in coffee leaves collected in three municipalities in the state of Minas Gerais, Brazil. There was a difference between the isolates for the studied variables, but without any relation to the type of symptom. The differences found were not associated with the origin of the isolates. The symptoms characterized as black spot were associated with different host conditions during the infection process.

scholarly journals MGS Esmeralda: new large seed mungbean cultivar

2008 ◽  
Vol 43 (6) ◽  
pp. 781-782 ◽  
Author(s):  
Rogério Faria Vieira ◽  
José Eustáquio Souza Carneiro ◽  
Trazilbo José de Paula Júnior ◽  
Roberto Fontes Araújo
Keyword(s):  
Powdery Mildew ◽  
Research And Development ◽  
Leaf Spot ◽  
Seed Mass ◽  
Minas Gerais ◽  
The State ◽  
Cercospora Leaf Spot ◽  
Large Seed ◽  
Development Center

Mungbean cultivar MGS Esmeralda was developed by Asian Vegetable Research and Development Center (Shanhua, Taiwan), as a result of crossing between the lines VC 1973A and VC 2768A. In ten trials conducted in the State of Minas Gerais, Brazil, it produced 13.5% more grains than 'Ouro Verde MG-2' (control cultivar), and its highest yield was 2,550 kg ha-1. The cultivar MGS Esmeralda is more susceptible to lodging, and its pods mature more uniformly than Ouro Verde MG-2 pods. One hundred-seed mass of 'MGS Esmeralda' ranged between 5.5 and 6.8 g. Both cultivars are susceptible to powdery mildew and cercospora leaf spot.

Infection process and defense response of two distinct symptoms of Cercospora leaf spot in coffee leaves

2021 ◽  
Author(s):  
Camila C. L. Andrade ◽  
Mário Lúcio Vilela de Resende ◽  
Silvino I. Moreira ◽  
Sandra M. Mathioni ◽  
Deila M. S. Botelho ◽  
...  
Keyword(s):  
Defense Response ◽  
Leaf Spot ◽  
Infection Process ◽  
Cercospora Leaf Spot

scholarly journals First Report of the Perfect Stage of Powdery Mildew of Sugar Beet in North Dakota Caused by Erysiphe polygoni

Plant Disease ◽  
2007 ◽  
Vol 91 (4) ◽  
pp. 470-470 ◽  
Author(s):  
C. A. Bradley ◽  
P. Burlakoti ◽  
R. S. Nelson ◽  
M. F. R. Khan
Keyword(s):  
Powdery Mildew ◽  
Sugar Beet ◽  
North Dakota ◽  
Leaf Spot ◽  
Genetic Recombination ◽  
The State ◽  
Cercospora Leaf Spot ◽  
First Report ◽  
Perfect Stage ◽  
Erysiphe Polygoni

Powdery mildew caused by Erysiphe polygoni was widespread on sugar beet (Beta vulgaris) in North Dakota during 2006. This disease is generally not prevalent in the state because of the application of fungicides, which also have efficacy against powdery mildew, for control of Cercospora leaf spot caused by Cercospora beticola. Because Cercospora leaf spot pressure was low in 2006, fewer fungicide applications were made in the state, thus allowing for more observations of powdery mildew. Leaf samples from four fields near Amenia, Minto, Prosper, and St. Thomas, ND were collected in mid-September to look for the perfect stage of E. polygoni, since this has recently been observed in Idaho, Colorado, Montana, and Nebraska (1–3). Only the leaves collected from the field near Amenia had visible immature (yellow and brown) globose ascomata; ascomata were not observed on the leaves collected in the other fields. Additional leaves were collected from the field near Amenia in early October; these leaves had immature and mature (black) globose ascomata that were 70 to 105 μm in diameter. Mature ascomata contained ovoid to elliptic asci with one to four hyaline-to-golden pigmented ascospores (20 to 25 × 12 to 20 μm). The color, shape, and size of ascomata, asci, and ascospores were similar to previously reported observations (1–4). The prevalence of the perfect stage in North Dakota is unknown, since no statewide surveys were conducted. To our knowledge, this is the first report of the perfect stage of E. polygoni on sugar beet in North Dakota. The occurrence of the perfect stage could lead to a means for overwintering in this area. Because of the means for genetic recombination, the risk of fungicide resistance and the development of races may increase. References: (1) J. J. Gallian and L. E. Hanson. Plant Dis. 87:200, 2003. (2) R. M. Harveson. Plant Dis. 88:1049, 2004. (3) B. Jacobsen et al. Plant Dis. 89:1362, 2005. (4) E. G. Ruppel. Powdery mildew. Pages 13–15 in: Compendium of Beet Diseases and Insects. E. D. Whitney and J. E. Duffus, eds. The American Phytopathological Society. St. Paul, MN, 1986.

scholarly journals Evaluation of Fungicides and Management Strategies against Cercospora Leaf Spot of Olive Caused by Pseudocercospora cladosporioides

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 271
Author(s):  
Joaquín Romero ◽  
Arantxa Ávila ◽  
Carlos Agustí-Brisach ◽  
Luis F. Roca ◽  
Antonio Trapero
Keyword(s):  
Leaf Spot ◽  
Mycelial Growth ◽  
Management Strategies ◽  
Conidial Germination ◽  
Field Conditions ◽  
Cercospora Leaf Spot ◽  
Wide Range ◽  
Traditional Strategy ◽  
Mediterranean Conditions

Cercospora leaf spot of olive (CLSO), caused by Pseudocercospora cladosporioides, is one of the most important foliar diseases of olives worldwide. This study aimed to evaluate the effect of a wide range of fungicides on mycelial growth and conidial germination of P. cladosporioides in vitro, and to evaluate the effect of several fungicides, application timings and management strategies (conservative and risky) to control CLSO under field conditions. Of the studied fungicides, strobilurin compounds and benomyl were the most effective active ingredients, followed by folpet, captan and maneb, in inhibiting mycelial growth and conidial germination. The pyraclostrobin + boscalid treatment was effective under field conditions, even without the application of supplementary copper. Treatments conducted in October or March were more effective than those conducted in May. Management strategies based on the author’s experience reduced copper applications up to 32.0% and 50.0% (conservative and risky strategy, respectively) in comparison to the reduction with the traditional strategy, without increasing CLSO incidence. This work provides useful information about effective formulations against CLSO and a reduction in unnecessary fungicide applications in an effort to implement IPM in olive orchards under Mediterranean conditions.

scholarly journals Resistance of Shrub and Groundcover Roses to Black Spot and Cercospora Leaf Spot, and Impact of Fungicide Inputs on the Severity of both Diseases

2005 ◽  
Vol 23 (2) ◽  
pp. 77-85 ◽  
Author(s):  
A.K. Hagan ◽  
M.E. Rivas-Davila ◽  
J.R. Akridge ◽  
J.W. Olive
Keyword(s):  
Powdery Mildew ◽  
Leaf Spot ◽  
Black Spot ◽  
Ground Cover ◽  
White Flower ◽  
Polar Ice ◽  
Cercospora Leaf Spot ◽  
Knock Out ◽  
Weather Patterns ◽  
The Impact

Abstract Reaction of selected shrub and ground cover roses to black spot, Cercospora leaf spot, and powdery mildew, as well as the impact of fungicide inputs on the control of the above diseases, was assessed from 1999 through 2003 in a simulated landscape planting in Brewton, AL. Chlorothalonil at 1.25 g ai/liter was applied at 2- and 4-week intervals from mid-March until October to randomly selected plants in each replicate. An unsprayed control was also included in each replicate. Although black spot was the predominate disease observed, a number of rose selections suffered from objectionable Cercospora leaf spot-induced leaf spotting and premature defoliation. Few mixed outbreaks of black spot and Cercospora leaf spot on a single selection were seen. In all years, significant differences in the reaction of rose selections to black spot and Cercospora leaf spot were noted. Of the roses damaged by black spot, the least leaf spot and defoliation were noted on the unsprayed Ice Meidiland®, Mystic Meidiland®, Red Cascade™, ‘Hansa’, ‘Pink Grootendorst’, ‘Pink Pet’, and to a lesser extent Carefree Wonder™ and Pearl Sevillana™. In a residential planting, monthly applications of chlorothalonil or other recommended fungicide would be needed to protect the above rose selections from a destructive black spot outbreak. ‘Betty Prior’, Bonica®, Cherry Meidiland®, First Light™, Kent™, Jeepers Creeper™, ‘Livin’ Easy™, Lilian Austin™, ‘Nearly Wild’, ‘Nozomi’, Butterfly rose, Ralph's Creeper™, Raven™, Royal Bonica™, ‘Sea Foam’, Sevillana™, and Sweet Chariot™ were susceptible to black spot. While black spot did not appreciably damage Carefree Delight™, Flower Carpet®, White Flower Carpet®, Fire Meidiland®, Fuchsia Meidiland®, Happy Trails™, ‘Petite Pink Scotch’, Polar Ice™, R. wichurana, The Fairy™, and ‘Therese Bugnet’, considerable Cercospora leaf spot development occurred on all of the above rose selections. Of these roses, Polar Ice™, Fuchsia Meidiland®, and Fire Meidiland® exhibited the highest resistance to Cercospora leaf spot and may not require any fungicide inputs to maintain plant health and vigor. Magic Carpet™ and Knock Out™ roses, which were susceptible and resistant to black spot, respectively, as well as Flower Carpet®, and White Flower Carpet® appeared to be poorly adapted to the hot and sometimes dry summer weather patterns of South Alabama. In nearly all years, chlorothalonil gave better control of both diseases when applied on a 2-week than on a 4-week schedule. Significant chlorothalonil-induced leaf burn was seen on First Light™, Flower Carpet®, ‘Hansa’, Happy Trails™, Magic Carpet™, Mystic Meidiland™, ‘Nozomi’, and Raven™. Consistent powdery mildew development was found only on ‘Therese Bugnet’ and to a lesser extent on Red Cascade™ and ‘Petite Pink Scotch’. Canopy spread of the roses that were heavily damaged by black spot and Cercospora leaf spot often was often reduced in size when compared with that of adjacent chlorothalonil-treated plants of the same selection. In contrast, little if any increase in growth was obtained with fungicide inputs for the more disease resistant rose selections.

scholarly journals Efficiency of green manures for Cercospora leaf spot management in coffee plants

2013 ◽  
Vol 38 (2) ◽  
pp. 122-127 ◽  
Author(s):  
Rogério Manuel de Lemos Cardoso ◽  
Júlio César Dias Chaves ◽  
Denilson Fantin ◽  
Valdir Lourenço Jr.
Keyword(s):  
Leaf Spot ◽  
Green Manures ◽  
Cercospora Leaf Spot ◽  
Coffee Plants

Cercospora leaf spot inToona ciliata: Epidemiology and infection process ofCercosporacf.alchemillicola

2018 ◽  
Vol 48 (6) ◽  
pp. e12451 ◽  
Author(s):  
Humberson Rocha Silva ◽  
Edson Ampélio Pozza ◽  
Paulo Estevão de Souza ◽  
Maria Alves Ferreira ◽  
Aurivan Soares Freitas ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Infection Process ◽  
Cercospora Leaf Spot

scholarly journals First Report of Cercospora coffeicola Causing Cercospora Leaf Spot of Castor Beans in Brazil

Plant Disease ◽  
2011 ◽  
Vol 95 (11) ◽  
pp. 1479-1479 ◽  
Author(s):  
A. G. C. Souza ◽  
L. A. Maffia
Keyword(s):  
Leaf Spot ◽  
Biofuel Production ◽  
Cercospora Leaf Spot ◽  
Alternative Source ◽  
Potato Dextrose Agar Medium ◽  
First Report ◽  
Natural Lighting ◽  
Leaf Spots ◽  
Cercospora Coffeicola ◽  
Coffee Plants

In a coffee (Coffea arabica) farm located in Ervália, Minas Gerais State, Brazil, we observed castor bean (CB; Ricinnus communis) plants growing as weeds. Currently, there is increasing interest in CB as a crop in Brazil because it is an alternative source for biofuel production, but there is little knowledge on CB diseases. According to reports from Costa Rica (2) and Malawi (3), Cercospora coffeicola can cause leaf spots in CB plants. Considering the increasing importance of Cercospora leaf spot on coffee and the expansion of CB plantings in Brazil, in 2008 we evaluated whether CB plants were susceptible to C. coffeicola. Healthy seedlings of an unknown CB cultivar were collected from the experimental coffee area in Ervália, transplanted to pots, and kept under greenhouse conditions. Each of two C. coffeicola isolates from coffee, obtained from the collection of the Departamento de Fitopatologia, was inoculated on two CB plants and three ‘Catuaí Vermelho’ coffee plants, each with four fully expanded leaves. Conidia were produced following a standard protocol (4). A suspension with 1 × 104 conidia ml–1 was sprayed with a DeVilbiss atomizer on both leaf surfaces until runoff, dispensing approximately 3 ml per leaf. As controls, two CB and three coffee plants were sprayed with distilled water. All treated plants were kept in a dew chamber at >90% relative humidity, 25°C, and with 12 h per day of light. After 48 h, the plants were placed in a greenhouse with natural lighting and an average temperature of 25 ± 3°C. Plants were checked at 3-day intervals for disease symptoms. On average, the incubation period (time between inoculation and appearance of the first leaf symptom) was 9 days and the latent period (time between inoculation and visualization of the first leaf sporulating lesion) was 12 days for the disease in CB. Both C. coffeicola isolates were pathogenic to all inoculated CB plants, in which approximately 20 spots developed per leaf. Control plants did not develop any symptoms. Leaf spots in CB plants were similar to those previously described (2): necrotic lesions that were black and purple with a yellowish halo and a pale white center. There was intense sporulation at the lesion center, and the conidia were hyaline, acicular to obclavate, nearly straight with truncate to subtruncate bases and acute tips, multiseptate, 2 to 4 × 40 to 150 μm and were produced in fascicles of conidiophores that were pale to medium brown, septate, and 4 to 6 × 20 to 275 μm (1,4). The pathogen was reisolated from the CB leaf spots, grown on potato dextrose agar medium, and the morphology of the colonies was similar to the colonies of the isolates from the C. coffeicola collection. The reisolated cultures were set to sporulate and reinoculated onto new healthy coffee and CB leaves, on which leaf spots developed. To our knowledge, this is the first report of castor beans as a host of C. coffeicola in Brazil. Considering the expansion of CB crops in Brazil, studies are needed to evaluate the susceptibility of the commercial CB cultivars that are grown in the country, particularly those planted close to coffee-production areas where Cercospora leaf spot is endemic and important. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Charles Chupp, Ithaca, NY, 1954. (2) E. Echandi. Turrialba 9:54, 1959. (3) M. A. Siddiqi. Trans. Br. Mycol. Soc. 54:415, 1970. (4) A. G. C. Souza et al. J. Phytopathol. 159:6, 2011.

Alternaria and Cercospora Leaf Spot Diseases of Niger (Guizotia abyssinica Cass.) – A Traditional Tribal Crop of South Gujarat, India, with Cost Benefit Ratio in Relation to Different Fungicides

2018 ◽  
Vol 51 (3) ◽  
pp. 89-99
Author(s):  
P.B. Sandipan ◽  
P.K. Jagtap ◽  
M.C. Patel
Keyword(s):  
Field Experiment ◽  
Seed Yield ◽  
Leaf Spot ◽  
Foliar Spray ◽  
Cost Benefit ◽  
Research Station ◽  
Guizotia Abyssinica ◽  
Cercospora Leaf Spot ◽  
Benefit Ratio ◽  
Cost Benefit Ratio

Abstract Niger (Guizotia abyssinica Cass.) is an important minor oil seed crop grown in dry areas grown mostly by tribal and interior places as life line of tribal segment. Tribal people mainly use its oil for cooking purpose, above than that there were also other uses. Hence, the niger crop should be protected from the infection. The crop is affected by number of fungal diseases. Therefore, a field experiment was formulated for three years with the four replications at the Niger Research Station (NRS) at Navsari Agricultural University (NAU), Vanarasi, Navsari (Gujarat) on the foliar diseases of GN-1 variety of niger crop. In this experiment, six different fungicides along with one control have been evaluated to control the Alternaria and Cercospora leaf spot diseases, out of which all the fungicidal treatments were significantly superior over the control. Here, foliar spray on the incidence of diseases was compared with the control (without any treatment). All the fungicidal treatments were significantly superior over the control to reduce Alternaria and Cercospora leaf spot diseases of Niger crop. Treatment of Carbendazim + Mancozeb (0.2 %) with two sprays first from the initiation of the disease and second after the interval of 15 days recorded the lowest incidence of Alternaria (14.56) and Cercospora (14.94) leaf spot diseases of niger and recorded the highest seed yield 337 seed yield kg/ha along with the net return with cost benefit ratio graph.

Analysis of the horizontal structure of a measurement and control geodetic network based on entropy

2013 ◽  
Vol 62 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Maria Mrówczyńska
Keyword(s):  
Geodetic Network ◽  
The State ◽  
Observation System ◽  
Optimum Number ◽  
Optimum Structure ◽  
Horizontal Structure ◽  
The Difference ◽  
And Control ◽  
Measurement And Control ◽  
Horizontal Displacements

Abstract The paper attempts to determine an optimum structure of a directional measurement and control network intended for investigating horizontal displacements. For this purpose it uses the notion of entropy as a logarithmical measure of probability of the state of a particular observation system. An optimum number of observations results from the difference of the entropy of the vector of parameters ΔHX̂ (x)corresponding to one extra observation. An increment of entropy interpreted as an increment of the amount of information about the state of the system determines the adoption or rejection of another extra observation to be carried out.

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