Urdbean web blight and its management strategies- A review

2018 ◽  
Author(s):  
Santosh Kumar ◽  
Amarendra Kumar Rolling Anal ◽  
H. S. Tripathi
Keyword(s):  
Relative Humidity ◽  
Management Strategies ◽  
Molecular Characteristics ◽  
Disease Development ◽  
Optimum Temperature ◽  
Yield Losses ◽  
Culture Morphology ◽  
Abiotic Constraints ◽  
Web Blight ◽  
Heavy Rains

The production and productivity of urdbean ranks lower in India as compared to the that of world average due to the biotic and abiotic constraints. Web blight of Urdbean is caused by Rhizoctonia solani Kuhn and is a soil borne pathogen and initial inoculums come mainly from soil splashes which fall on leaves during heavy rains. Respective optimum temperature and relative humidity i.e. 26–28oC and 90–100% favours disease development chronically. The pathogen can survive very longer in the absence of a host either as sclerotia or thick walled brown hyphae in plants debris. Currently the disease is prevalent in many countries across the globe. The pathogen is highly variable in terms of its pathogenicity, culture, morphology, biochemical and molecular characteristics. The severity of this disease is directly linked with the population of viable sclerotia in the soil. Yield losses due to this disease vary in between 20-30% depending upon prevailing conditions.

scholarly journals Comparative Genomics Used to Predict Virulence Factors and Metabolic Genes among Monilinia Species

2021 ◽  
Vol 7 (6) ◽  
pp. 464
Author(s):  
Marina Marcet-Houben ◽  
Maria Villarino ◽  
Laura Vilanova ◽  
Antonieta De Cal ◽  
Jan A. L. van Kan ◽  
...  
Keyword(s):  
Brown Rot ◽  
Weather Conditions ◽  
Genomic Variation ◽  
Disease Development ◽  
Stone Fruits ◽  
Yield Losses ◽  
Future Studies ◽  
Metabolic Genes ◽  
Pome Fruits ◽  
Significant Yield

Brown rot, caused by Monilinia spp., is among the most important diseases in stone fruits, and some pome fruits (mainly apples). This disease is responsible for significant yield losses, particularly in stone fruits, when weather conditions favorable for disease development appear. To achieve future sustainable strategies to control brown rot on fruit, one potential approach will be to characterize genomic variation among Monilinia spp. to define, among others, the capacity to infect fruit in this genus. In the present work, we performed genomic and phylogenomic comparisons of five Monilinia species and inferred differences in numbers of secreted proteins, including CAZy proteins and other proteins important for virulence. Duplications specific to Monilinia were sparse and, overall, more genes have been lost than gained. Among Monilinia spp., low variability in the CAZome was observed. Interestingly, we identified several secondary metabolism clusters based on similarity to known clusters, and among them was a cluster with homology to pyriculol that could be responsible for the synthesis of chloromonilicin. Furthermore, we compared sequences of all strains available from NCBI of these species to assess their MAT loci and heterokaryon compatibility systems. Our comparative analyses provide the basis for future studies into understanding how these genomic differences underlie common or differential abilities to interact with the host plant.

Outbreaks of crown rot in Fragaria x ananassa caused by Neopestalotiopsis mesopotamica in Ecuador

2021 ◽  
pp. 520
Author(s):  
Hamilton Octavio Intriago- Reyna ◽  
Fernando José Rivas- Figueroa ◽  
Álvaro Mauricio Rivera- Casignia ◽  
Pablo Israel Álvarez- Romero ◽  
Ana Francisca Tibúrcia Amorim Ferreira e Ferreira
Keyword(s):  
Causative Agent ◽  
Fragaria X Ananassa ◽  
Crown Rot ◽  
Molecular Characteristics ◽  
Disease Development ◽  
Conidial Morphology ◽  
Fungal Isolates ◽  
The World ◽  
Efficient Control ◽  
Etiological Agents

Strawberry crown rot is one of the most important diseases in Ecuador, with an incidence of up to 70% in the field. In the world, the strawberry crown rot is caused by different etiological agents, which makes efficient control of the disease difficult. In this study, 12 samples of strawberry plants were collected, at different stages of disease development, to determine the causative agent in Ecuador. The fungal isolates, consistent with the isolation, were identified and characterized using molecular and morphological approaches, and finally, Koch's postulate was carried out. Based on the form of growth, mycelial color, conidial morphology, and molecular characteristics (sequencing of the ITS and EF-1α region), the pathogen associated with the symptoms showed 99% similarity with the species Neopestalotiopsis mesopotamica. The result of Koch's postulates showed symptoms similar to those observed in field plants, in addition, the same inoculated isolate was recovered from artificially inoculated tissues. This is the first report of this fungus causing strawberry crown rot in Ecuador and in the world.

scholarly journals Effects of Temperature, Relative Humidity, and Plant Age on Bacterial Disease of Onion Plants

2019 ◽  
Vol 20 (4) ◽  
pp. 200-206
Author(s):  
Kim E. Tho ◽  
Elizabeth Brisco-McCann ◽  
Prissana Wiriyajitsomboon ◽  
Mary K. Hausbeck
Keyword(s):  
Relative Humidity ◽  
Management Strategies ◽  
Bacterial Pathogen ◽  
Plant Age ◽  
Effect Of Temperature ◽  
Bacterial Disease ◽  
Disease Symptoms ◽  
Foliar Disease ◽  
Progress Curve ◽  
Effects Of Temperature

Foliar disease of onion in Michigan, caused by Pantoea agglomerans, Pantoea ananatis, or Enterobacter cowanii, has recently become a concern to producers. The objective of this study was to determine the effect of temperature, relative humidity (RH), and plant age in growth chamber and greenhouse experiments on onion plants inoculated with each pathogen. A significant level of disease resulted from each pathogen at 25 to 30°C, with strong positive associations detected using regression analysis between the area under the disease progress curve (AUDPC) and temperature. RH also significantly influenced symptom development. Foliar disease symptoms developed sooner and were more severe when RH was high (80 to 100%) but was limited at RH < 60%. Significant positive associations between RH and AUDPC, as described by linear regression, were also detected. When 6- to 14-week-old plants were inoculated with each bacterial pathogen, susceptibility increased significantly with age. These results provide insight into the epidemiology of P. agglomerans, P. ananatis, and E. cowanii bacterial pathogens of onions in Michigan and can assist in the development and timing of management strategies.

Anthracnose of Florida Beggarweed (Desmodium tortuosum) Caused byColletotrichum truncatum

Weed Science ◽  
1988 ◽  
Vol 36 (3) ◽  
pp. 329-334 ◽  
Author(s):  
John Gardina ◽  
Robert H. Littrell ◽  
Richard T. Hanlin
Keyword(s):  
Relative Humidity ◽  
Host Specificity ◽  
Plant Species ◽  
Fungal Pathogen ◽  
Disease Development ◽  
Colletotrichum Truncatum ◽  
Optimum Conditions ◽  
Cotyledon Stage ◽  
Chamber Studies ◽  
Growth Chamber Studies

Greenhouse and growth chamber studies were conducted to determine conditions for infection of the fungal pathogenColletotrichum truncatum(Schw.) Andrus and Moore on Florida beggarweed (Desmodium tortuosum(Sw.) DC. # DEDTO and to determine the host specificity of this fungus. Optimum conditions for disease development were 14 to 16 h incubation in 100% relative humidity (RH) at 24 to 29 C. Control of Florida beggarweed with 105to 107C. truncatumspores/ml was greatest in the cotyledon stage and decreased with plant age. Ten of 18Desmodiumspecies tested were susceptible to the Florida beggarweed isolate ofC. truncatumbut 13 other plant species and varieties were resistant and 61 were immune.

Yield losses in wheat from yellow spot: a disease-loss relationship derived from single tillers

1981 ◽  
Vol 32 (6) ◽  
pp. 851 ◽  
Author(s):  
RG Rees ◽  
RJ Mayer ◽  
GJ Platz
Keyword(s):  
Grain Yield ◽  
Harvest Index ◽  
Wheat Yield ◽  
Yellow Spot ◽  
Disease Development ◽  
Yield Losses ◽  
Grain Development ◽  
Pyrenophora Tritici Repentis ◽  
Percentage Loss ◽  
Average Loss

The effect of yellow spot (Pyrenophora tritici-repentis) on wheat yield has been examined with a single-tiller technique. The disease was assessed on c. 1000 tagged main stems in each of five wheat crops. Grain yield, its components, and harvest index were measured on each tiller. In most cases these response variables were significantly correlated with yellow spot levels. The disease-loss relationship, L = 0.26X, was developed where L is the percentage loss in grain yield per main head and X is the average level of yellow spot on the top two leaves at around the milk stage of grain development. From four of the crops examined, an average loss of 12.7 % in grain yield per main head was estimated. Under environmental conditions which particularly favour disease development, the losses derived from this relationship are probably underestimated.

scholarly journals Research Priorities for Rice Pest Management in Tropical Asia: A Simulation Analysis of Yield Losses and Management Efficiencies

2004 ◽  
Vol 94 (7) ◽  
pp. 672-682 ◽  
Author(s):  
Laetitia Willocquet ◽  
Francisco A. Elazegui ◽  
Nancy Castilla ◽  
Luzviminda Fernandez ◽  
Kenneth S. Fischer ◽  
...  
Keyword(s):  
Pest Management ◽  
Management Strategies ◽  
Research Priorities ◽  
Sheath Blight ◽  
Brown Spot ◽  
Yield Losses ◽  
Leaf Blast ◽  
Tropical Asia ◽  
Neck Blast ◽  
Rice Pest

A simulation study was conducted to assess the current and prospective efficiency of rice pest management and develop research priorities for lowland production situations in tropical Asia. Simulation modeling with the RICEPEST model provided the flexibility required to address varying production situations and diverse pest profiles (bacterial leaf blight, sheath blight, brown spot, leaf blast, neck blast, sheath rot, white heads, dead hearts, brown plant-hoppers, insect defoliators, and weeds). Operational definitions for management efficacy (injury reduction) and management efficiency (yield gain) were developed. This approach enabled the modeling of scenarios pertaining to different pest management strategies within the agroecological contexts of rice production and their associated pest injuries. Rice pests could be classified into two broad research priority-setting categories with respect to simulated yield losses and management efficiencies. One group, including weeds, sheath blight, and brown spot, consists of pests for which effective pest management tools need to be developed. The second group consists of leaf blast, neck blast, bacterial leaf blight, and brown plant-hoppers, for which the efficiency of current management methods is to be maintained. Simulated yield losses in future production situations indicated that a new type of rice plant with high-harvest index and high-biomass production (“New Plant Type”) was more vulnerable to pests than hybrid rice. Simulations also indicated that the impact of deployment of host resistance (e.g., through genetic engineering) was much larger when targeted against sheath blight than when targeted against stem borers. Simulated yield losses for combinations of production situations and injury profiles that dominate current lowland rice production in tropical Asia ranged from 140 to 230 g m-2. For these combinations, the simulated efficiency of current pest management methods, expressed in terms of relative yield gains, ranged from 0.38 to 0.74. Overall, the analyses indicated that 120 to 200 × 106 tons of grain yield are lost yearly to pests over the 87 × 106 ha of lowland rice in tropical Asia. This also amounts to the potential gain that future pest management strategies could achieve, if deployed.

scholarly journals Differences Between Ascospores and Conidia of Didymella rabiei in Spore Germination and Infection of Chickpea

2007 ◽  
Vol 97 (12) ◽  
pp. 1600-1607 ◽  
Author(s):  
Antonio Trapero-Casas ◽  
Walter J. Kaiser
Keyword(s):  
Disease Severity ◽  
Spore Germination ◽  
Opposite Effect ◽  
Disease Development ◽  
Optimum Temperature ◽  
Water Potentials ◽  
Wetness Period ◽  
Moisture Conditions ◽  
Germ Tubes ◽  
Plant Surfaces

Studies were performed to compare the germination and infection of ascospores and conidia of Didymella rabiei under different temperature and moisture conditions. Germination of ascospores and conidia on cover glasses coated with water agar began after 2 h, with maximum germination (>95%) occurring in 6 h at 20°C. No germination occurred at 0 and 35°C. Ascospores germinated more rapidly than conidia at all temperatures. Germination declined rapidly as the water potential varied from 0 to –4 MPa, although some germination occurred at –6 MPa at 20 and 25°C. Ascospores germinated over a wider range of water potentials than conidia and their germ tubes were longer than those of conidia at most water potentials and temperatures. The optimum temperature for infection and disease development by both ascospores and conidia was around 20°C. Disease severity was higher when ascospores were discharged directly onto plant surfaces from naturally infested chickpea debris compared with aqueous suspensions of ascospores and conidia sprayed onto plants Disease severity increased as the length of the wetness period increased. When dry periods of 6 to 48 h occurred immediately after inoculation, disease severity decreased, except for the shorter periods which had the opposite effect. Disease severity was higher with ascospore inoculum when no dry periods occurred after inoculation.

scholarly journals Characterizing the Sphaceloma Fungus, Causal Agent of Superelongation Disease in Cassava

Plant Disease ◽  
2000 ◽  
Vol 84 (4) ◽  
pp. 423-428 ◽  
Author(s):  
Elizabeth Alvarez ◽  
Martha L. Molina
Keyword(s):  
Dna Analysis ◽  
Random Amplified Polymorphic Dna ◽  
Management Strategies ◽  
Restriction Enzymes ◽  
Colony Growth ◽  
Molecular Characteristics ◽  
Intermediate Reaction ◽  
Polymerase Chain ◽  
The Tropics ◽  
Selection Of

The fungus Sphaceloma manihoticola causes superelongation disease in cassava, a starchy root crop grown widely in the tropics. Isolates were collected from infected plants grown in six localities of Colombia. Morphological analyses of the fungus showed that colony growth and color are not stable characteristics over time. Pathogenicity studies, using the susceptible cassava variety M Col 22 and the resistant M Ven 77, showed that M Col 22 was tolerant of 29% of pathogen isolates studied and had an intermediate reaction to 71%. Variety M Ven 77 also showed tolerance of 16.2% of the isolates, had an intermediate reaction to 80.6%, and was susceptible to 3.2%. Significant cultivar × isolate interactions indicated pathogenic specialization. This study is the first to describe this pathogen's molecular characteristics. A homogeneous and reporducible band of about 545 bp was obtained with polymerase chain reaction which, when digested by restriction enzymes, showed an equal pattern of bands for all isolates. The isolates thus belonged to one species. Random amplified polymorphic DNA analysis revealed intraspecific genetic diversity. By better understanding the pathogen, we can apply more appropriate disease management strategies, such as selection of germ plasm tolerant of superelongation disease.

scholarly journals Cutinase and Other Lipolytic Esterases Protect Bean Leaves from Infection by Rhizoctonia solani

1998 ◽  
Vol 11 (6) ◽  
pp. 514-522 ◽  
Author(s):  
Diana M. Parker ◽  
Wolfram Köller
Keyword(s):  
Rhizoctonia Solani ◽  
Esterase Activity ◽  
Venturia Inaequalis ◽  
Protective Mechanism ◽  
Disease Development ◽  
Mechanical Wounding ◽  
Small Areas ◽  
Pathogenesis Related ◽  
Web Blight ◽  
Bean Leaves

The results describe a novel activity of fungal cutinase, the protection of bean leaves from disease. Development of web blight symptoms on bean leaves infected with Rhizoctonia solani (AG-1) was prevented in the presence of cutinase purified from Venturia inaequalis. Instead of disease, small areas of tissue necrosis became visible, and the tissue in which the pathogen was restricted displayed strong autofluorescence beneath the inoculation sites. Mechanical wounding of the leaf surface had no effect on disease development and the permeability of the cuticle was not increased by cutinase action, indicating that surface wounding was not the cause for this novel activity of cutinase. A comparative study involving cutinase and other serine hydrolases revealed that the disease prevention resided in the lipolytic esterase activity rather than the cutinase activity. The pattern of expression of four pathogenesis-related (PR) protein genes provided no evidence for the modulation of known resistance responses of bean leaves in response to cutinase action. The protective mechanism of the esterase activity remains unknown.

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