scholarly journals Glassy-Winged Sharpshooters Expected to Increase Plant Disease

2000 ◽  
Vol 1 (1) ◽  
pp. 3 ◽  
Author(s):  
Alexander H. Purcell ◽  
Stuart R. Saunders

As it moves through California, the new pest known as glassy-winged sharpshooter (GWSS) may significantly increase the spread of plant diseases caused by the bacterium Xylella fastidiosa. The bacterium causes Pierce's disease of grapevines, almond leaf scorch and the newly recognized oleander leaf scorch disease. Currently, almond leaf scorch is a minor problem for California's almonds, but if GWSS becomes established in significant numbers in or near almond orchards, it might increase the incidence of almond leaf scorch. Our studies show that GWSS and two other sharpshooter species can transmit X. fastidiosa from diseased oleanders to healthy oleanders. GWSS also can transmit Pierce's disease strains of the bacterium from grapevine to grapevine and to almond trees. The oleander strain of the bacterium did not infect grapevines, but the ability of GWSS to transmit Pierce's disease strains may increase the spread of this lethal grapevine disease in vineyards bordering citrus orchards or other habitats where invading GWSS may establish permanent populations. Posted 27 December 2000.

Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1131-1138 ◽  
Author(s):  
R. Hernandez-Martinez ◽  
D. A. Cooksey ◽  
F. P. Wong

Sweetgum dieback and leaf scorch of purple-leafed plum are two new diseases of southern California landscape ornamentals. Samplings were conducted in 2003 and 2004 and 28 of 105 sweetgum (Liquidambar styraciflua) and 38 of 62 purple-leafed plum (Prunus cerasifera) plants tested positive for Xylella fastidiosa by enzyme linked immunosorbent assay. In all, 3 strains of X. fastidiosa were isolated from sweetgum and 13 from purple-leafed plum. All sweetgum strains and some purple-leafed plum strains grew on PW but not PD3 media. Strain PC045 from purple-leafed plum and strain LS022 from sweetgum were inoculated into their original hosts in addition to almond, oleander, and grapevine plants. Sweetgum plants also were inoculated with strains causing Pierce's disease, almond leaf scorch, and oleander leaf scorch. Strain PC045 caused symptoms in purple-leafed plum and almond plants within 6 months, and the pathogen was recovered from 93 and 100% of inoculated plants, respectively. Inoculation of grapevine and oleander plants with PC045 did not result in disease or recovery of the pathogen. In all, 5 of 25 sweetgum plants inoculated with LS022 showed symptoms after 9 months, and the pathogen was recovered from 3 of these plants. Inoculation of grapevine, oleander, and almond with LS022 resulted in no disease or recovery of the pathogen from the plants. A strain of Pierce's disease, a strain of oleander leaf scorch, and two strains from almond did not cause disease in sweetgum. These results confirm the role of X. fastidiosa strains as pathogens of purple-leafed plum and sweetgum, and that strains from sweetgum are unique in their host range.


2008 ◽  
Vol 74 (12) ◽  
pp. 3652-3657 ◽  
Author(s):  
J. Chen ◽  
E. Civerolo ◽  
K. Tubajika ◽  
S. Livingston ◽  
B. Higbee

ABSTRACT Xylella fastidiosa is a gram-negative plant pathogenic bacterium that causes almond leaf scorch disease (ALSD) and Pierce's disease (PD) of grape in many regions of North America and Mexico. Of the two 16S rRNA gene genotypes described in California, A genotype strains cause ALSD only and G genotype strains cause both PD and ALSD. While G genotype strains cause two different diseases, little is known about their genetic variation. In this study, we identified a putative protease locus, PD0218 (pspB), in the genome of X. fastidiosa and evaluated the variation at this locus in X. fastidiosa populations. PD0218 contains tandem repeats of ACDCCA, translated to threonine and proline (TP), upstream of the putative protease conserved domain. Among 116 X. fastidiosa ALSD and PD strains isolated from seven locations in California, tandem repeat numbers (TRNs) varied from 9 to 47, with a total of 30 TRN genotypes, indicating that X. fastidiosa possesses an active mechanism for contracting and expanding tandem repeats at this locus. Significant TRN variation was found among PD strains (mean = 29.9), which could be further divided into two TRN groups: PD-Gsmall (mean = 17.3) and PD-Glarge (mean = 44.3). Less variation was found in ALSD strains (mean = 21.7). The variation was even smaller after ALSD strains were subdivided into the A and G genotypes (mean = 13.3, for the G genotype; mean = 27.1, for the A genotype). Genetic variation at the PD0218 locus is potentially useful for sensitive discrimination of X. fastidiosa strains. However, TRN stability, variation range, and correlation to phenotypes should be evaluated in epidemiological applications such as pathotype identification and delineation of pathogen origin.


Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 473
Author(s):  
Diego Olmo ◽  
Alicia Nieto ◽  
David Borràs ◽  
Marina Montesinos ◽  
Francesc Adrover ◽  
...  

Xylella fastidiosa (Xf) is a vascular plant pathogen native to the Americas. In 2013, it was first reported in Europe, implicated in a massive die-off of olive trees in Apulia, Italy. This finding prompted mandatory surveys across Europe, successively revealing that the bacterium was already established in some distant areas of the western Mediterranean. To date, the Balearic Islands (Spain) hold the major known genetic diversity of Xf in Europe. Since October 2016, four sequence types (ST) belonging to the subspecies fastidiosa (ST1), multiplex (ST7, ST81), and pauca (ST80) have been identified infecting 28 host species, including grapevines, almond, olive, and fig trees. ST1 causes Pierce’s disease (PD) and together with ST81 are responsible for almond leaf scorch disease (ALSD) in California, from where they were introduced into Mallorca in around 1993, very likely via infected almond scions brought for grafting. To date, almond leaf scorch disease affects over 81% of almond trees and Pierce’s disease is widespread in vineyards across Mallorca, although producing on average little economic impact. In this perspective, we present and analyze a large Xf-hosts database accumulated over four years of field surveys, laboratory sample analyses, and research to understand the underlying causes of Xf emergence and spread among crops and wild plants in the Balearic Islands. The impact of Xf on the landscape is discussed.


2002 ◽  
Vol 92 (7) ◽  
pp. 721-728 ◽  
Author(s):  
N. W. Schaad ◽  
D. Opgenorth ◽  
P. Gaush

Molecular-based techniques, such as polymerase chain reaction (PCR), can reduce the time needed for diagnosis of plant diseases when compared with classical isolation and pathogenicity tests. However, molecular techniques still require 2 to 3 days to complete. To the best of our knowledge, we describe for the first time a real-time PCR technique using a portable Smart Cycler for one-hour on-site diagnosis of an asymptomatic plant disease. Pierce's disease (PD) of grape, caused by the fastidious bacterium Xylella fastidiosa, causes serious losses in grapes in California and the southeastern United States. The disease has been difficult to diagnose because typical leaf scorching symptoms do not appear until late (June and after) in the season and the organism is very difficult to isolate early in the season. Sap and samples of macerated chips of secondary xylem from trunks of vines were used in a direct real-time PCR without extraction of DNA. Using two different sets of primers and probe, we diagnosed PD in 7 of 27 vines (26%) from four of six vineyards sampled 10 to 12 days after bud break in Kern, Tulare, and Napa counties of California. The diagnosis was confirmed by isolation of Xylella fastidiosa from two of the original PCR positive samples and later from symptomatic leaf petioles of four out of four vines from one vineyard that were originally PCR positive.


Plant Disease ◽  
2011 ◽  
Vol 95 (2) ◽  
pp. 158-165 ◽  
Author(s):  
Tiesen Cao ◽  
Joseph H. Connell ◽  
Margot Wilhelm ◽  
Bruce C. Kirkpatrick

Field grown 2-year-old almond trees (Prunus dulcis cvs. Butte, Carmel, Mission, Ne Plus Ultra, Padre, Peerless, Price, Solano, Sonora, and Thompson) were mechanically inoculated with Xylella fastidiosa in the growing seasons of 2002 and 2003 to study the effect of inoculation date on the movement and colonization of X. fastidiosa and the overwintering persistence of almond leaf scorch disease (ALS) in these cultivars. X. fastidiosa was inoculated into the base of current-season growing shoots in April, May, June, July, August, September, and October. Almond trees inoculated in spring months developed more ALS-symptomatic leaves and more extensive within-plant spread of X. fastidiosa by the end of the current growing season compared with trees inoculated in July, August, September, and October. Trees inoculated in June developed the most severe ALS symptoms during the season in which they were inoculated. Trees inoculated in June and July 2002 had significantly higher disease ratings in 2003 than inoculations made in August and October 2002. Based on disease ratings observed in 2003, 1 year after inoculation, Sonora and Solano were the most ALS susceptible, Mission and Price intermediate, and Carmel, Padre, Ne Plus Ultra, Butte, Peerless, and Thompson were the least susceptible cultivars for allowing X. fastidiosa to overwinter and cause disease the following year. Assessment of all trees in August 2004 indicated that trees inoculated in June and July 2002 had a significantly higher amount of ALS-infected branches than trees inoculated in other months. Butte, Carmel, Padre, and Thompson cultivars had no symptomatic branches, while X. fastidiosa infections persisted or colonized new branches in Sonora, Solano, Peerless, Price, Mission, and Ne Plus Ultra. Based on the 2004 assessment, Sonora was the most susceptible cultivar. Surveys of a diseased orchard in Chico, CA showed large differences in ALS incidence in four almond cultivars. Nonpareil and Peerless had significantly greater incidence of disease than Butte and Carmel over the 2 years surveyed. These data suggest that cultivar susceptibility and the time of X. fastidiosa infection are important factors in determining the persistence of ALS in almond trees.


2001 ◽  
Vol 67 (2) ◽  
pp. 895-903 ◽  
Author(s):  
Mavis Hendson ◽  
Alexander H. Purcell ◽  
Deqiao Chen ◽  
Chris Smart ◽  
Magalie Guilhabert ◽  
...  

ABSTRACT Strains of Xylella fastidiosa isolated from grape, almond, maple, and oleander were characterized by enterobacterial repetitive intergenic consensus sequence-, repetitive extragenic palindromic element (REP)-, and random amplified polymorphic DNA (RAPD)-PCR; contour-clamped homogeneous electric field (CHEF) gel electrophoresis; plasmid content; and sequencing of the 16S-23S rRNA spacer region. Combining methods gave greater resolution of strain groupings than any single method. Strains isolated from grape with Pierce's disease (PD) from California, Florida, and Georgia showed greater than previously reported genetic variability, including plasmid contents, but formed a cluster based on analysis of RAPD-PCR products,NotI and SpeI genomic DNA fingerprints, and 16S-23S rRNA spacer region sequence. Two groupings of almond leaf scorch (ALS) strains were distinguished by RAPD-PCR and CHEF gel electrophoresis, but some ALS isolates were clustered within the PD group. RAPD-PCR, CHEF gel electrophoresis, and 16S-23S rRNA sequence analysis produced the same groupings of strains, with RAPD-PCR resolving the greatest genetic differences. Oleander strains, phony peach disease (PP), and oak leaf scorch (OLS) strains were distinct from other strains. DNA profiles constructed by REP-PCR analysis were the same or very similar among all grape strains and most almond strains but different among some almond strains and all other strains tested. Eight of 12 ALS strains and 4 of 14 PD strains of X. fastidiosa isolated in California contained plasmids. All oleander strains carried the same-sized plasmid; all OLS strains carried the same-sized plasmid. A plum leaf scald strain contained three plasmids, two of which were the same sizes as those found in PP strains. These findings support a division of X. fastidiosaat the subspecies or pathovar level.


EDIS ◽  
1969 ◽  
Vol 2004 (18) ◽  
Author(s):  
Tracy Conklin ◽  
Russell F. Mizell, III

The glassy-winged sharpshooter, Homalodisca coagulata (Say), is a large leafhopper species native to the southeastern United States. It is one of the main vectors of the bacterium Xylella fastidiosa, a plant pathogen that causes a variety of plant diseases, including phony peach disease of peach and Pierce's disease of grape. Though usually not a serious pest in the area of its native distribution, the glassy-winged sharpshooter has recently been introduced into southern California, where it has become a serious threat to viticulture due to its ability to vector Pierce's disease.  This document is EENY-274, one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: October 2002. Revised: July 2004. EENY-274/IN552: Glassy-Winged Sharpshooter, Homalodisca vitripennis (=coagulata) (Germar) (Insecta: Hemiptera: Cicadellidae: Cicadellinae) (ufl.edu)


1980 ◽  
Vol 58 (18) ◽  
pp. 1986-1993 ◽  
Author(s):  
Suzanne S. Hearon ◽  
James L. Sherald ◽  
Stanley J. Kostka

Ultrathin sections of leaves from American elms (Ulmus americana L.), sycamores (Platanus spp.), and two red oak species (Quercus spp.) that exhibited leaf scorch were examined by transmission electron microscopy. Rod-shaped, ripple-walled bacteria resembling the Pierce's disease organism were found consistently in tracheary elements of the primary and secondary veins of diseased plants. Smaller, ripple-walled, densely stained, irregular-shaped bodies (SDB) were found also in a matrix that lined the inner walls or filled the lumina of the tracheary elements. In leaf scorch affected American elms the bacteria were 0.3–0.4 μrn × 0.9–2.4 μm, with rounded ends. Fimbriae-like structures radiated from a few organisms. Bacteria were frequently embedded in a matrix. Pit cavities and the ends of tracheary elements were often filled with the bacteria–matrix complex. Rod-shaped bacteria were not as numerous in the diseased sycamore and oak as in diseased elm; however, SDB's were more numerous. Bacteria in sycamore (1.0–1.8 μm) and oak (1.0–2.0 μm) were slightly shorter than those in elm, many had numerous fimbriae-like hairs, and some were tapered at one end. Indirect fluorescent antibody staining showed a serological relationship between bacteria extracted from elm and oak and the Pierce's disease bacterium.


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