Gray Leaf Spot of Perennial Ryegrass

2003 ◽  
Vol 4 (1) ◽  
pp. 10 ◽  
Author(s):  
Philip F. Harmon ◽  
Richard Latin
Keyword(s):  
Host Range ◽  
Lolium Perenne ◽  
Geographic Distribution ◽  
Perennial Ryegrass ◽  
Magnaporthe Oryzae ◽  
Leaf Spot ◽  
Gray Leaf Spot ◽  
And Storage ◽  
Symptoms And Signs ◽  
Methods Of Isolation

Diagnosis of gray leaf spot (caused by Magnaporthe oryzae) of perennial ryegrass (Lolium perenne) is discussed in detail, including the disease's symptoms and signs, host range, taxonomy, and geographic distribution, as well as methods of isolation, identification, and storage of M. oryzae. Accepted for publication 29 January 2003. Published 10 March 2003.

Detection and Identification of Botrytis Species Associated with Neck Rot, Scape Blight, and Umbel Blight of Onion

2006 ◽  
Vol 7 (1) ◽  
pp. 38 ◽  
Author(s):  
Martin I. Chilvers ◽  
Lindsey J. du Toit
Keyword(s):  
Host Range ◽  
Geographic Distribution ◽  
Detection And Identification ◽  
And Storage ◽  
Symptoms And Signs ◽  
Methods Of Isolation

Diagnosis of detection and identification of Botrytis species associated with neck rot, scape blight, and umbel blight of onion are discussed in detail, including the disease's symptoms and signs, host range, taxonomy, and geographic distribution, as well as methods of isolation, identification (including macroscopic vs. microscopic characteristics), and storage of the pathogens. Accepted for publication 7 August 2006. Published 27 November 2006.

scholarly journals Diagnosis of Common Root Rot of Wheat and Barley

2003 ◽  
Vol 4 (1) ◽  
pp. 11 ◽  
Author(s):  
D. E. Mathre ◽  
R. H. Johnston ◽  
W. E. Grey
Keyword(s):  
Host Range ◽  
Geographic Distribution ◽  
Root Rot ◽  
Common Root ◽  
Common Root Rot ◽  
The Common ◽  
And Storage ◽  
Symptoms And Signs ◽  
Methods Of Isolation

Diagnosis of common root rot of wheat and barley is discussed in detail, including its symptoms and signs, host range, taxonomy, and geographic distribution, as well as methods of isolation, identification, and storage of the common root rot pathogen. Accepted for publication 17 July 2003. Published 19 August 2003.

Sudden Oak Death and Associated Diseases Caused by Phytophthora ramorum

2003 ◽  
Vol 4 (1) ◽  
pp. 12 ◽  
Author(s):  
J. M. Davidson ◽  
S. Werres ◽  
M. Garbelotto ◽  
E. M. Hansen ◽  
D. M. Rizzo
Keyword(s):  
Host Range ◽  
Geographic Distribution ◽  
Leaf Blight ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Associated Diseases ◽  
And Storage ◽  
Symptoms And Signs ◽  
Methods Of Isolation

Diagnosis of Sudden Oak Death, ramorum leaf blight, and ramorum shoot dieback on a wide variety of hosts are discussed in detail, including the symptoms and signs, host range, taxonomy, and geographic distribution, as well as methods of isolation, identification, and storage of Phytophthora ramorum, the pathogen which causes Sudden Oak Death. Accepted for publication 6 June 2003. Published 7 July 2003.

scholarly journals Comparative Genetic Analysis of Magnaporthe oryzae Isolates Causing Gray Leaf Spot of Perennial Ryegrass Turf in the United States and Japan

Plant Disease ◽  
2007 ◽  
Vol 91 (5) ◽  
pp. 517-524 ◽  
Author(s):  
Y. Tosa ◽  
W. Uddin ◽  
G. Viji ◽  
S. Kang ◽  
S. Mayama
Keyword(s):  
United States ◽  
Perennial Ryegrass ◽  
Magnaporthe Oryzae ◽  
Leaf Spot ◽  
Genetic Relationships ◽  
The United States ◽  
Gray Leaf Spot ◽  
Genetic Lineage ◽  
Type I ◽  
Type Ii

Gray leaf spot caused by Magnaporthe oryzae is a serious disease of perennial ryegrass (Lolium perenne) turf in golf course fairways in the United States and Japan. Genetic relationships among M. oryzae isolates from perennial ryegrass (prg) isolates within and between the two countries were examined using the repetitive DNA elements MGR586, Pot2, and MAGGY as DNA fingerprinting probes. In all, 82 isolates of M. oryzae, including 57 prg isolates from the United States collected from 1995 to 2001, 1 annual ryegrass (Lolium multiflorum) isolate from the United States collected in 1972, and 24 prg isolates from Japan collected from 1996 to 1999 were analyzed in this study. Hybridization with the MGR586 probe resulted in approximately 30 DNA fragments in 75 isolates (designated major MGR586 group) and less than 15 fragments in the remaining 7 isolates (designated minor MGR586 group). Both groups were represented among the 24 isolates from Japan. All isolates from the United States, with the exception of one isolate from Maryland, belonged to the major MGR586 group. Some isolates from Japan exhibited MGR586 fingerprints that were identical to several isolates collected in Pennsylvania. Similarly, fingerprinting analysis with the Pot2 probe also indicated the presence of two distinct groups: isolates in the major MGR586 group showed fingerprinting profiles comprising 20 to 25 bands, whereas the isolates in the minor MGR586 group had less than 10 fragments. When MAGGY was used as a probe, two distinct fingerprint types, one exhibiting more than 30 hybridizing bands (type I) and the other with only 2 to 4 bands (type II), were identified. Although isolates of both types were present in the major MGR586 group, only the type II isolates were identified in the minor MGR586 group. The parsimony tree obtained from combined MGR586 and Pot2 data showed that 71 of the 82 isolates belonged to a single lineage, 5 isolates formed four different lineages, and the remaining 6 (from Japan) formed a separate lineage. This study indicates that the predominant groups of M. oryzae associated with the recent outbreaks of gray leaf spot in Japan and the United States belong to the same genetic lineage.

scholarly journals A Rapid PCR-Based Method for the Detection of Magnaporthe oryzae from Infected Perennial Ryegrass

Plant Disease ◽  
2003 ◽  
Vol 87 (9) ◽  
pp. 1072-1076 ◽  
Author(s):  
Philip F. Harmon ◽  
Larry D. Dunkle ◽  
Richard Latin
Keyword(s):  
Perennial Ryegrass ◽  
Magnaporthe Oryzae ◽  
Leaf Spot ◽  
Leaf Tissue ◽  
Gray Leaf Spot ◽  
Rapid Pcr ◽  
Field Samples ◽  
Multiple Copies ◽  
Serious Disease ◽  
Time Required

Gray leaf spot caused by Magnaporthe oryzae is a serious disease of perennial ryegrass in the midwestern United States. Symptoms of gray leaf spot can be confused with those caused by other fungal diseases that also are common during periods of high temperatures and ample moisture. Because turf managers must select appropriate fungicides for remedial treatment, accurate and timely identification of the pathogen is essential for efficient and effective disease management. We developed and evaluated a polymerase chain reaction (PCR)-based method to detect M. oryzae in infected perennial ryegrass tissue. The method utilizes a commercially available kit that is used for isolation and amplification of plant DNA from leaf tissue. The kit protocol was modified and found to be reliable for the extraction of M. oryzae DNA from infected perennial ryegrass. Primers were designed to amplify a 687-bp fragment of the Pot2 transposon that is found in multiple copies in the genome of the pathogen. The protocol amplified amounts of purified DNA as low as 5 pg and consistently and specifically detected M. oryzae in single diseased leaf blades as well as in field samples of infected perennial ryegrass. The total time required for detection was approximately 4 to 8 h.

Pink Hibiscus Mealybug Identification

2006 ◽  
Vol 7 (1) ◽  
pp. 43 ◽  
Author(s):  
Amanda Hodges ◽  
Greg Hodges
Keyword(s):  
Host Range ◽  
Geographic Distribution ◽  
Pink Hibiscus Mealybug ◽  
Symptoms And Signs ◽  
Methods Of Isolation

Identification of pink hibiscus mealybug is discussed in detail, including its symptoms and signs, host range, taxonomy, and geographic distribution, as well as methods of isolation, identification, and preservation. Accepted for publication 18 March 2006. Published 14 April 2006.

scholarly journals Silicon-Induced Systemic Defense Responses in Perennial Ryegrass Against Infection by Magnaporthe oryzae

2015 ◽  
Vol 105 (6) ◽  
pp. 748-757 ◽  
Author(s):  
Alamgir Rahman ◽  
Christopher M. Wallis ◽  
Wakar Uddin
Keyword(s):  
Disease Management ◽  
Perennial Ryegrass ◽  
Magnaporthe Oryzae ◽  
Leaf Spot ◽  
Calcium Silicate ◽  
Fungal Pathogens ◽  
Disease Incidence ◽  
Defense Responses ◽  
Gray Leaf Spot ◽  
Integrated Disease Management

Sustainable integrated disease management for gray leaf spot of perennial ryegrass may involve use of plant defense elicitors with compatible traditional fungicides to reduce disease incidence and severity. Silicon (Si) has previously been identified as a potential inducer or modulator of plant defenses against different fungal pathogens. To this end, perennial ryegrass was inoculated with the causal agent of gray leaf spot, Magnaporthe oryzae, when grown in soil that was nonamended or amended with three different levels of calcium silicate (1, 5, or 10 metric tons [t]/ha). When applied at a rate of 5 t/ha, calcium silicate was found to significantly suppress gray leaf spot in perennial ryegrass, including a significant reduction of disease incidence (39.5%) and disease severity (47.3%). Additional studies observed nonpenetrated papillae or cell-wall appositions harboring callose, phenolic autofluorogens, and lignin-associated polyphenolic compounds in grass grown in the Si-amended soil. Regarding defense-associated enzyme levels, only following infection did grass grown in Si-amended soil exhibit greater activities of peroxidase and polyphenol oxidase than equivalent inoculated control plants. Also following infection with M. oryzae, grass levels of several phenolic acids, including chlorogenic acid and flavonoids, and relative expression levels of genes encoding phenylalanine ammonia lyase (PALa and PALb) and lipoxygenase (LOXa) significantly increased in Si-amended plants compared with that of nonamended control plants. These results suggest that Si-mediated increase of host defense responses to fungal pathogens in perennial ryegrass has a great potential to be part of an effective integrated disease management strategy against gray leaf spot development.

Isolation, Identification, and Pathogenicity of Phytophthora Blight of Pigeonpea

2018 ◽  
Vol 19 (3) ◽  
pp. 233-236
Author(s):  
Mamta Sharma ◽  
Raju Ghosh
Keyword(s):  
Geographic Distribution ◽  
Phytophthora Blight ◽  
Causal Organism ◽  
Diagnosis And Management ◽  
And Storage ◽  
Symptoms And Signs ◽  
Methods Of Isolation

Phytophthora blight is an emerging threat in pigeonpea. This article briefly discusses diagnosis of Phytophthora blight on pigeonpea including the symptoms and signs, taxonomy, and geographic distribution. Methods of isolation, identification, and storage of Phytophthora cajani (causal organism of Phytophthora blight) are also discussed. This information will be useful to all researchers involved in the diagnosis and management of Phytophthora blight of pigeonpea.

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