scholarly journals First Report of Xylella fastidiosa Associated with Leaf Scorch in Black Oak in Washington, D.C.

Plant Disease ◽  
2004 ◽  
Vol 88 (2) ◽  
pp. 224-224 ◽  
Author(s):  
Q. Huang
Keyword(s):  
Xylella Fastidiosa ◽  
The United States ◽  
Enzyme Linked Immunosorbent Assay ◽  
Bacterial Suspension ◽  
White Oak ◽  
First Report ◽  
Leaf Petiole ◽  
Leaf Scorch ◽  
Pcr Product ◽  
Black Oak

Bacterial leaf scorch caused by Xylella fastidiosa has been reported in 17 species of oak including bur, pin, red, scarlet, shingle, and white oaks (3). In September 2002, a leaf scorch symptom characterized by marginal necrosis of leaves bordered by a darker brown band was observed in a mature black oak (Quercus velutina Lam.) at the U.S. National Arboretum in Washington, D.C. The leaf petiole of the black oak was processed in general extraction buffer (Agdia, Inc., Elkhart, IN) contained in a FastDNA lysing matrix tube using the FastPrep FP120 instrument (Qbiogene, Inc., Carlsbad, CA) (1). The leaf petiole extract reacted with an antiserum specific for X. fastidiosa (Agadia, Inc.) in an enzyme-linked immunosorbent assay (ELISA). A slow-growing bacterium was cultured from leaf petioles of the affected black oak tree by soaking the surface-sterilized, finely cut leaf petioles in sterile water for 30 min, followed by spreading the bacterial suspension on periwinkle wilt plates (1). When the cultured bacterium was subjected to polymerase chain reaction (PCR) with primers specific for X. fastidiosa (2), a 472-bp PCR product was detected. The PCR product was confirmed to be the predicted X. fastidiosa product by sequencing and sequence comparison with the reported genomic sequence of X. fastidiosa. ELISA and bacterial isolation from leaf petioles of a nearby symptomless white oak (Q. alba L.) tree were negative. To our knowledge, this is the first report of X. fastidiosa associated with leaf scorch in black oak in the United States, expanding the host range of the bacterium in economically important landscape tree species. References: (1) Q. Huang and J. L. Sherald. Curr. Microbiol. 48:73, 2004. (2) M. R. Pooler and J. S. Hartung. Curr. Microbiol. 31:377, 1995. (3) J. L. Sherald. Xylella fastidiosa, A bacterial pathogen of landscape trees. Page 191 in: Shade Tree Wilt Diseases, C. L. Ash, ed. The American Phytopathological Society, 2001.

scholarly journals Discovery and Characterization of Xylella fastidiosa Strains in Southern California Causing Mulberry Leaf Scorch

Plant Disease ◽  
2006 ◽  
Vol 90 (9) ◽  
pp. 1143-1149 ◽  
Author(s):  
R. Hernandez-Martinez ◽  
T. R. Pinckard ◽  
H. S. Costa ◽  
D. A. Cooksey ◽  
F. P. Wong
Keyword(s):  
Southern California ◽  
Xylella Fastidiosa ◽  
Random Amplified Polymorphic Dna ◽  
Intergenic Spacer ◽  
Genomic Analysis ◽  
The United States ◽  
Enzyme Linked Immunosorbent Assay ◽  
Leaf Scorch ◽  
Mulberry Leaf ◽  
White Mulberry

Mulberry leaf scorch (MLS), caused by Xylella fastidiosa, is a disease of mulberry trees in the United States that has largely been documented from locations in the eastern and central areas of the country. MLS was recently detected for the first time in white mulberry (Morus alba) trees in southern California. Four MLS-strains were isolated from two locations and confirmed as X. fastidiosa by enzyme-linked immunosorbent assay (ELISA), direct isolation of the pathogen, and use of the X. fastidiosa-specific PCR primers RST31-33. Isolated strains were characterized by the sequencing of their 16S-23S rDNA intergenic spacer regions (ISR) and random amplified polymorphic DNA (RAPD) analysis and subsequent comparison with a previously characterized MLS-strain (Mulberry-VA) and representatives of X. fastidiosa subsp. fastidiosa, X. fastidiosa subsp. multiplex, and X. fastidiosa subsp. sandyi. MLS-strains isolated from California were distinct from strains causing almond leaf scorch, oleander leaf scorch, and Pierce's disease and similar to the Mulberry-VA-strain. The ISR sequences of two MLS-strains, MLS063 and MLS059, were 100% identical to that of the Mulberry-VA sequence, whereas MLS012 and MLS024 were 99.8 and 99.6% identical to the Mulberry-VA-strain and 99.4% identical among themselves. Genomic analysis using RAPD revealed no differences among the four strains. The pathogenicity of one strain, MLS063, was confirmed by inoculation of glasshouse-grown white mulberry plants. Three months after inoculation, the pathogen was recovered from 21 of 25 inoculated plants, and 5 of 25 plants were dead within a year of inoculation. Inoculation of grapevines and oleanders with MLS063 did not result in any disease or recovery of the pathogen up to 1 year later, showing that this strain was not cross-infective to these hosts.

scholarly journals First Report of Pantoea agglomerans Causing a Leaf Blight and Bulb Rot of Onions in Georgia

Plant Disease ◽  
2006 ◽  
Vol 90 (12) ◽  
pp. 1551-1551 ◽  
Author(s):  
D. G. Edens ◽  
R. D. Gitaitis ◽  
F. H. Sanders ◽  
C. Nischwitz
Keyword(s):  
The United States ◽  
Field Trials ◽  
Positive Control ◽  
Universal Primers ◽  
Enzyme Linked Immunosorbent Assay ◽  
Bacterial Suspension ◽  
Water Control ◽  
First Report ◽  
Negative Results ◽  
Foliar Blight

In April 2006, sweet onions (Allium cepa) that were grown in Wayne County, GA displayed symptoms typical of either center rot caused by Pantoea ananatis or a foliar blight caused by Iris yellow spot virus (IYSV). After samples tested negative for IYSV by enzyme-linked immunosorbent assay and polymerase chain reaction, isolations were made from basal areas of leaves of infected plants where healthy and diseased tissues converged. All samples yielded yellow colonies on trypticase soy broth agar (TSBA) that were nonfluorescent when transferred to King's medium B. Four strains were characterized and tentatively identified as a Pantoea sp. by yellow pigmentation of colonies, oxidative and fermentative use of glucose, and lack of oxidase. However, the inability to produce indole from tryptophan, negative ice-nucleation activity, ability to reduce nitrate to nitrite, and the presence of phenylalanine deaminase were characteristics more typical of P. agglomerans than P. ananatis. Furthermore, all test strains utilized cellobiose, raffinose, lactose, gelatin, melibiose, and malonate. The identity of the bacterium was confirmed as P. agglomerans by BIOLOG (Hayward, CA). In addition, the 16S gene was amplified using universal primers (forward 5′-AGTTTGATCCTGGCTCAG-3′ and reverse 5′-TACCTTGTTACGACTTCGTCCCA-3′ (1) and sequenced. A BLAST search of the sequence against the NIH GenBank nucleotide library also confirmed the identity of the onion pathogen as P. agglomerans (97% identity) by having 8 of the top 10 bacteria providing significant alignments identified as P. agglomerans. The remaining two matches were uncultured bacteria from environmental samples. To confirm pathogenicity, two onion plants for each of the four test strains were inoculated with a turbid, aqueous bacterial suspension (~1 × 108 CFU ml-1) or sterile water in the lab (n = 8) and the field (n = 8). In addition, two plants each were inoculated with P. ananatis as a positive control and with a water blank and a nonpathogenic strain of P. agglomerans from peach (Png 86-2) as negative controls. All test strains of P. agglomerans produced severe blighting and withering of onion leaves in 4 days, while the water control and Png 86-2 were negative. Results were the same for both lab and field trials. Bacteria recovered from the plants infected with the test strains demonstrated the same characteristics of P. agglomerans as described above. Although P. agglomerans was originally reported as a pathogen of onion in South Africa (2), to the best of our knowledge, this is the first report of P. agglomerans causing a disease of onions in the United States. The long-term impact on the onion industry at this time is unknown. However, considering the close relationship of this organism with P. ananatis and the similarity of disease symptoms with those caused by center rot, there is potential that this bacterium could become established in the onion-growing area of Georgia and become part of a center rot ‘complex’. References: (1) T. De Baere et al. J. Clin. Microbiol. 42:4393, 2004. (2) M. J. Hattingh and D. F. Walters. Plant Dis. 65:615, 1981.

scholarly journals First Report of Oleander Leaf Scorch Caused by Xylella fastidiosa in Texas

Plant Disease ◽  
2004 ◽  
Vol 88 (9) ◽  
pp. 1049-1049 ◽  
Author(s):  
Q. Huang ◽  
R. H. Brlansky ◽  
L. Barnes ◽  
W. Li ◽  
J. S Hartung
Keyword(s):  
San Antonio ◽  
Xylella Fastidiosa ◽  
Enzyme Linked Immunosorbent Assay ◽  
Bacterial Disease ◽  
Bacterial Isolation ◽  
First Report ◽  
Leaf Scorch ◽  
Chlorotic Mottling ◽  
Red Variety

Bacterial leaf scorch caused by Xylella fastidiosa has been reported on oleander in California (3) and Florida (4). In June 2002, leaf scorch symptoms including chlorotic mottling of leaves, necrosis on leaf tips or whole leaves, defoliation, and shortened internodes were observed in oleander plants at various locations in Texas, including Galveston, Harlingen, Austin, San Antonio, and El Campo. The symptomatic varieties Calypso, Commandant Barthelemy, Lane Taylor Sealy, Little Red, Mrs. George Roeding, Mrs. Runge, Scarlet Beauty, and Petite Salmon, as well as symptomless varieties, Turner's Shari D and Sugarland from Moody Gardens in Galveston, Texas were sampled. All samples were tested for the presence of X. fastidiosa using enzyme-linked immunosorbent assay (ELISA) and bacterial isolation according to the methods of Huang and Sherald (2). All symptomatic varieties reacted positively in ELISA, and colonies characteristic of X. fastidiosa were isolated from all eight symptomatic varieties 10 to 15 days after incubation at 28°C. The colonies were confirmed to be X. fastidiosa using polymerase chain reaction (PCR) (2). ELISA tests and bacterial isolations from the symptomless Shari D and Sugarland varieties were negative. Membrane entrapment immunofluorescence (MEIF) (1) using the antibody CREC 26 to X. fastidiosa was also done on three of the symptomatic varieties and one asymptomatic variety obtained from Moody Gardens, and fluorescing bacteria were found only in the three symptomatic varieties. Symptomatic samples of Petite Salmon, one pink variety and one red variety obtained from a residential area west of Galveston, and a red oleander in Harlingen, TX, also tested positive with MEIF. Other ELISA-positive samples were obtained from symptomatic oleanders from Austin, San Antonio, and El Campo, TX. The X. fastidiosa bacteria isolated from the variety Lane Taylor Sealy were used to inoculate three red oleander plants by making an 8-cm-long vertical cut into the stem and then in 15 locations injecting approximately 15 μl of a X. fastidiosa suspension (108–9 cells per ml). The cut area was wrapped with Parafilm after inoculation, and the plants were kept at 29°C in a greenhouse. Three healthy red oleanders were inoculated with periwinkle wilt liquid medium for controls. Approximately 3 months after inoculation, chlorotic mottling along the edges of leaves was observed in the oleanders inoculated with X. fastidiosa, and the bacterium was reisolated from symptomatic leaves as described above. No symptoms were observed on the control plants, and bacterial isolation from the control plants was also negative. To our knowledge, this is the first report to show the causal role of X. fastidiosa in oleander leaf scorch and the presence of the disease in different locations in Texas, extending the geographic range of this important bacterial disease. References: (1) R. H. Brlansky et al. Plant Dis. 74:863, 1990. (2) Q. Huang and J. L. Sherald. Curr. Microbiol. 48:73, 2004. (3) A. H. Purcell et al. Phytopathology 89:53, 1999. (4) R. L. Wichman and D. L. Hopkins. Plant Dis. 84:198, 2000.

scholarly journals First Report of Grapevine leafroll associated virus-3 in American Vitis spp. Grapevines in Washington State

Plant Disease ◽  
2006 ◽  
Vol 90 (11) ◽  
pp. 1461-1461 ◽  
Author(s):  
M. J. Soule ◽  
K. C. Eastwell ◽  
R. A. Naidu
Keyword(s):  
New York ◽  
Economic Impact ◽  
Virus Disease ◽  
The United States ◽  
Washington State ◽  
The State ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rt Pcr ◽  
First Report ◽  
Table Grapes

Washington State is the largest producer of juice grapes (Vitis labruscana ‘Concord’ and Vitis labrusca ‘Niagara’) and ranks second in wine grape production in the United States. Grapevine leafroll disease (GLD) is the most wide spread and economically significant virus disease in wine grapes in the state. Previous studies (2) have shown that Grapevine leafroll associated virus-3 (GLRaV-3) is the predominant virus associated with GLD. However, little is known about the incidence and economic impact of GLD on juice and table grapes. Because typical GLD symptoms may not be obvious among these cultivars, the prevalence and economic impact of GLD in Concord and Niagara, the most widely planted cultivars in Washington State, has received little attention from the grape and nursery industries. During the 2005 growing season, 32 samples from three vineyards and one nursery of ‘Concord’ and three samples from one nursery of ‘Niagara’ were collected randomly. Petiole extracts were tested by single-tube reverse transcription-polymerase chain reaction (RT-PCR; 3) with primers LC 1 (5′-CGC TAG GGC TGT GGA AGT ATT-3′) and LC 2 (5′-GTT GTC CCG GGT ACC AGA TAT-3′), specific for the heat shock protein 70 homologue (Hsp70h gene) of GLRaV-3 (GenBank Accession No. AF037268). One ‘Niagara’ nursery sample and eleven ‘Concord’ samples from the three vineyards tested positive for GLRaV-3, producing a single band of the expected size of 546 bp. The ‘Niagara’ and six of the ‘Concord’ RT-PCR products were cloned in pCR2.1 (Invitrogen Corp, Carlsbad, CA) and the sequences (GenBank Accession Nos. DQ780885, DQ780886, DQ780887, DQ780888, DQ780889, DQ780890, and DQ780891) compared with the respective sequence of a New York isolate of GLRaV-3 (GenBank Accession No. AF037268). The analysis revealed that GLRaV-3 isolates from ‘Concord’ and ‘Niagara’ share nucleotide identities of 94 to 98% and amino acid identities and similarities of 97 to 98% with the Hsp70h gene homologue of the New York isolate of GLRaV-3. Additional testing by double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) using antibodies specific to GLRaV-3 (BIOREBA AG, Reinach, Switzerland) further confirmed these results in the ‘Niagara’ and two of the ‘Concord’ isolates. GLRaV-3 has previously been reported in labrusca cvs. Concord and Niagara in western New York (4) and Canada (1), but to our knowledge, this is the first report of GLRaV-3 in American grapevine species in the Pacific Northwest. Because wine and juice grapes are widely grown in proximity to each other in Washington State and grape mealybug (Pseudococcus maritimus), the putative vector of GLRaV-3, is present in the state vineyards, further studies will focus on the role of American grapevine species in the epidemiology of GLD. References: (1) D. J. MacKenzie et al. Plant Dis. 80:955, 1996. (2) R. R. Martin et al. Plant Dis. 89:763, 2005. (3) A. Rowhani et al. ICGV, Extended Abstracts, 13:148, 2000. (4) W. F. Wilcox et al. Plant Dis. 82:1062, 1998.

scholarly journals First Report of Plum pox virus (Sharka Disease) in Prunus persica in the United States

Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 202-202 ◽  
Author(s):  
L. Levy ◽  
V. Damsteegt ◽  
R. Welliver
Keyword(s):  
Prunus Persica ◽  
Virus Disease ◽  
Sandwich Elisa ◽  
Pcr Amplification ◽  
The United States ◽  
Enzyme Linked Immunosorbent Assay ◽  
Plum Pox Virus ◽  
Rt Pcr ◽  
Peach Fruit ◽  
First Report

Plum pox (Sharka) is the most important virus disease of Prunus in Europe and the Mediterranean region and is caused by Plum pox potyvirus (PPV). In September 1999, PPV-like symptoms were observed in peach fruit culls in a packinghouse in Pennsylvania. All symptomatic fruit originated from a single block of peach (P. persica cv. Encore) in Adams County. Trees in the block exhibited ring pattern symptoms on their leaves. A potyvirus was detected in symptomatic fruit using the Poty-Group enzyme-linked immunosorbent assay (ELISA) test from Agdia (Elkhart, IN). Reactions for symptomatic peach fruit and leaves also were positive using triple-antibody sandwich ELISA with the PPV polyclonal antibody from Bioreba (Carrboro, NC) for coating, the Poty-Group monoclonal antibody (MAb; Agdia) as the intermediate antibody, and double-antibody sandwich ELISA with PPV detection kits from Sanofi (Sanofi Diagnostics Pasteur, Marnes-La-Coquette, France) and Agdia and the REAL PPV kit (Durviz, Valencia, Spain) containing universal (5B) and strain typing (4DG5 and AL) PPV MAbs (1). PPV also was identified by immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) amplification and subsequent sequencing of the 220-bp 3′ noncoding region (2) (>99% sequence homology to PPV) and by IC-RT-PCR amplification of a 243-bp product in the coat protein (CP) gene (1). The virus was identified as PPV strain D based on serological typing with strainspecific MAbs and on PCR-restriction fragment length polymorphism of the CP IC-RT-PCR product with Rsa1 and Alu1 (1). This is the first report of PPV in North America. References: (1) T. Candresse et al. Phytopathology 88:198, 1998. (2) L. Levy and A. Hadidi. EPPO Bull. 24:595, 1994.

Pecan Bacterial Leaf Scorch, Caused by Xylella fastidiosa, Is Endemic in Georgia Pecan Orchards

2018 ◽  
Vol 19 (4) ◽  
pp. 284-287 ◽  
Author(s):  
Clive H. Bock ◽  
Jonathan E. Oliver ◽  
Chunxian Chen ◽  
Michael H. Hotchkiss ◽  
Katherine L. Stevenson ◽  
...  
Keyword(s):  
Yield Loss ◽  
Xylella Fastidiosa ◽  
Severe Disease ◽  
The United States ◽  
Susceptible Cultivar ◽  
Leaf Scorch ◽  
Central Production ◽  
Cape Fear ◽  
Production Areas ◽  
Bacterial Leaf Scorch

Pecan bacterial leaf scorch (PBLS), caused by Xylella fastidiosa, can cause severe disease in some pecan cultivars, resulting in yield loss. Only recently has some information been obtained regarding the distribution and extent of the disease in pecan in any state in the United States. With emphasis on a susceptible cultivar, Cape Fear, we sampled a total of 91 trees in eight orchards from the southwestern and central production areas in Georgia (GA) and found 60.4% of trees sampled infected, most showing symptoms of PBLS. Further multilocus sequence typing from 16 of these trees confirmed presence X. fastidiosa. The results confirm that X. fastidiosa is widespread geographically in GA, and different cultivars may be infected. This is the first definitive report confirming X. fastidiosa causing PBLS in different pecan producing areas and cultivars in GA.

scholarly journals Distribution of Xylella fastidiosa in Oaks in Florida and Its Association with Growth Decline in Quercus laevis

Plant Disease ◽  
1998 ◽  
Vol 82 (5) ◽  
pp. 569-572 ◽  
Author(s):  
E. L. Barnard ◽  
E. C. Ash ◽  
D. L. Hopkins ◽  
R. J. McGovern
Keyword(s):  
Immunosorbent Assay ◽  
Xylella Fastidiosa ◽  
Shoot Length ◽  
Enzyme Linked Immunosorbent Assay ◽  
Oak Decline ◽  
Widespread Occurrence ◽  
Leaf Scorch ◽  
Growth Decline ◽  
Quercus Laevis

A survey of more than 200 trees has documented the widespread occurrence of Xylella fastidiosa in Florida oak populations. The pathogen was detected readily via enzyme-linked immunosorbent assay in oaks exhibiting decline or leaf scorch symptoms and was infrequently detected in asymptomatic trees. It was also associated with reduced growth in Quercus laevis as measured by current-year shoot length. The occurrence of X. fastidiosa in Q. laevis and the evidence for its occurrence in Q. incana represent first reports for these oak hosts. The role of X. fastidiosa in oak decline scenarios deserves further attention.

scholarly journals First Report of Pecan Bacterial Leaf Scorch Caused by Xylella fastidiosa in Pecan (Carya illinoinensis) in Arizona, New Mexico, California, and Texas

Plant Disease ◽  
2017 ◽  
Vol 101 (11) ◽  
pp. 1949-1949 ◽  
Author(s):  
A. E. Hilton ◽  
Y-.K. Jo ◽  
K. Cervantes ◽  
R. A. Stamler ◽  
J. J. Randall ◽  
...  
Keyword(s):  
New Mexico ◽  
Xylella Fastidiosa ◽  
Carya Illinoinensis ◽  
First Report ◽  
Leaf Scorch ◽  
Bacterial Leaf Scorch

scholarly journals First Report of Leaf Blight on Fan Columbine (Aquilegia flabellata) Caused by Rhizoctonia solani AG 4 in Italy

Plant Disease ◽  
2009 ◽  
Vol 93 (4) ◽  
pp. 433-433 ◽  
Author(s):  
A. Garibaldi ◽  
G. Gilardi ◽  
D. Bertetti ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Rhizoctonia Solani ◽  
Aqueous Suspension ◽  
Morphological Characteristics ◽  
The United States ◽  
Leaf Blight ◽  
Herbaceous Plant ◽  
Pathogenicity Test ◽  
First Report ◽  
Leaf Petiole

Aquilegia flabellata (Ranunculaceae), fan columbine, is a perennial herbaceous plant with brilliant blue-purple flowers with white petal tips. It can also be grown for cut flower production. In April of 2008, in several nurseries located near Biella (northern Italy), a leaf blight was observed on 10 to 15% of potted 30-day-old plants grown on a sphagnum peat substrate at 15 to 20°C and relative humidity of 80 to 90%. Semicircular, water-soaked lesions developed on leaves just above the soil line at the leaf-petiole junction and later along the leaf margins. Lesions expanded over several days along the midvein until the entire leaf was destroyed. Blighted leaves turned brown, withered, and abscised. Severely infected plants died. Diseased tissue was disinfested for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA) amended with 25 mg/liter streptomycin sulfate. A fungus with the morphological characteristics of Rhizoctonia solani was consistently recovered, then transferred and maintained in pure culture. Ten-day-old mycelium grown on PDA at 22 ± 1°C appeared light brown, rather compact, and had radial growth. Sclerotia were not present. Isolates obtained from affected plants successfully anastomosed with tester isolate AG 4 (AG 4 RT 31, obtained from tobacco plants). Results were consistent with other reports on anastomosis reactions (2). Pairings were also made with tester isolates of AG 1, 2.1, 2.2, 3, 6, 7, 11, and BI with no anastomoses observed between the recovered and tester isolates. The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 648-bp fragment showed a 100% homology with the sequence of R. solani AG-4 AB000018. The nucleotide sequence has been assigned GenBank Accession No. FJ 534555. For pathogenicity tests, the inoculum of R. solani was prepared by growing the pathogen on PDA for 10 days. Five plants of 30-day-old A. flabellata were grown in 3-liter pots. Inoculum consisting of an aqueous suspension of PDA and mycelium disks (5 g of mycelium + agar per plant) was placed at the collar of plants. Five plants inoculated with water and PDA fragments alone served as control treatments. Plants were maintained in a greenhouse at temperatures between 20 and 24°C. The first symptoms, similar to those observed in the nursery, developed 7 days after the artificial inoculation. R. solani was consistently reisolated from infected leaves and stems. Control plants remained healthy. The pathogenicity test was carried out twice with similar results. The presence of R. solani AG1-IB on A. flabellata has been reported in Japan (4), while in the United States, Rhizoctonia sp. is described on Aquilegia sp. (3). This is, to our knowledge, the first report of leaf blight of A. flabellata caused by R. solani in Italy as well as in Europe. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. E. Carling. Grouping in Rhizoctonia solani by hyphal anastomosis reactions. In: Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. Kluwer Academic Publishers, The Netherlands, 1996. (3) D. F. Farr et al. Fungi on Plants and Products in the United States. The American Phytopathological Society, St Paul, MN, 1989. (4) E. Imaizumi et al. J. Gen. Plant Pathol. 66:210, 2000.

scholarly journals First Report of Xylella fastidiosa Infecting Citrus in Costa Rica

Plant Disease ◽  
2005 ◽  
Vol 89 (6) ◽  
pp. 687-687 ◽  
Author(s):  
E. Aguilar ◽  
W. Villalobos ◽  
L. Moreira ◽  
C. M. Rodríguez ◽  
E. W. Kitajima ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Costa Rica ◽  
Sweet Orange ◽  
Enzyme Linked Immunosorbent Assay ◽  
Negative Bacterium ◽  
Gram Negative ◽  
First Report ◽  
Leaf Petiole ◽  
Orange Trees ◽  
Das Elisa

Citrus variegated chlorosis (CVC) is an important disease mainly of sweet orange (Citrus sinensis (L.) Osbeck) cultivars. It was first described in Brazil in the state of Sā Paulo in 1987 (4). The disease has spread to all Brazilian states that grow citrus and is affecting more than one-third of the orange trees grown in Brazil. CVC is caused by Xylella fastidiousa, a xylem-limited, gram-negative bacterium. During the last 4 years, symptoms including leaf interveinal chlorosis, stunting, canopy dieback, and hard and undersized fruits, similar to those caused by CVC (3), appeared in sweet orange trees used as shade plants for coffee plantations and as fence posts in Costa Rica. Necrotic lesions on the abaxial side of the leaves as reported in Brazil were rarely observed. Leaf petiole samples from 25 symptomatic sweet orange trees reacted positively with a X fastidiosa-specific antiserum (AGDIA Inc., Elkart, IN) in a double-sandwich antibody enzyme-linked immunosorbent assay (DAS-ELISA). A fastidious, gram-negative bacterium identified as X. fastidiosa using DAS-ELISA was isolated on perwinkle wilt (PW) medium plates (1) from citrus stems showing CVC symptoms, but not from asymptomatic trees. The isolated colonies were circular and opalescent with diameters of 2 to 3 mm and were clearly visible within 6 to 7 days after streaking. Petiole sections from symptomatic plants observed with scanning electron microscopy showed rod-shaped bacteria with rippled cell walls tightly packed in xylem vessels, as described for X. fastidiosa previously (2), and with transmission electron microscopy, the bacteria were morphologically similar to those reported previously for CVC (2). To our knowledge, this is the first report of X. fastidiosa associated with citrus in Costa Rica. References: (1) M. J. Davis et al. Curr. Microbiol. 6:309, 1981. (2) J. S. Hartung et al. Phytopathology 84:591, 1994. (3) R. F. Lee et al. Summa Phytopathol. 19:123, 1993. (4) V. Rossetti et al. 1990, C.R. Acad. Sci. (Paris) 310:345–349.

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