Bacterial leaf scorch

{{Short description|Bacterial disease of plants}}

{{infobox plant disease

| name = Bacterial leaf scorch

| image = 2013-05-04 14 07 38 Large Pin Oak (Quercus palustris) stricken with bacterial leaf scorch during leaf-out near the house at 988 Terrace Boulevard in Ewing, New Jersey.JPG

| caption = Large pin oak (Quercus palustris) stricken with bacterial leaf scorch during leaf-out

| common_names = BLS

| hosts = trees and crops

| causal_agents = Xylella fastidiosa

| vectors = leafhoppers

| distribution =

| treatment =

}}

Bacterial leaf scorch (commonly abbreviated BLS, also called bacterial leaf spot) is a disease state affecting many crops, caused mainly by the xylem-plugging bacterium Xylella fastidiosa.{{cite web|url=https://www.fs.usda.gov/naspf/programs/forest-health-protection|title=Forest Health Protection - Northeastern Area State and Private Forestry|website=www.fs.usda.gov|access-date=2019-06-11|archive-date=2019-06-07|archive-url=https://web.archive.org/web/20190607193825/https://www.fs.usda.gov/naspf/programs/forest-health-protection|url-status=live}} It can be mistaken for ordinary leaf scorch caused by cultural practices such as over-fertilization.

Hosts

BLS can be found on a wide variety of hosts, ranging from ornamental trees (elm, maple, oak) and shrubs, to crop species including blueberry and almond.

  • Xylella fastidiosa is known to cause BLS in a very wide range of plants. Each of its subspecies has have a different host range.{{cite journal |last1=Cavalieri |first1=Vincenzo |last2=Fasanelli |first2=Elisa |last3=Gibin |first3=Davide |last4=Gutierrez Linares |first4=Alicia |last5=La Notte |first5=Pierfederico |last6=Pasinato |first6=Luca |last7=Delbianco |first7=Alice |title=Update of the Xylella spp. host plant database – Systematic literature search up to 31 December 2023 |journal=EFSA Journal |date=July 2024 |volume=22 |issue=7 |doi=10.2903/j.efsa.2024.8898}}
  • The multiplex subspecies causes BLS of pecans.
  • Bacterial spot of peppers and tomatoes is caused by the bacteria Xanthomonas campestris pv. vesicatoria, which has since been divided into four pathovars in three species.{{cite web |title=Xanthomonas euvesicatoria pv. euvesicatoria (XANTEU)[Overview]{{!}} EPPO Global Database |url=https://gd.eppo.int/taxon/XANTEU |website=gd.eppo.int |quote=One of the bacteria causing bacterial spot of tomato and pepper, together with Xanthomonas euvesicatoria pv. perforans, Xanthomonas hortorum pv. gardneri, Xanthomonas vesicatoria.}}
  • Bacterial spot of peaches is caused by the bacteria Xanthomonas arboricola pv. pruni. It also infects almonds.{{cite journal |last1=Garita‐Cambronero |first1=Jerson |last2=Palacio‐Bielsa |first2=Ana |last3=Cubero |first3=Jaime |title=Xanthomonas arboricola pv. pruni , causal agent of bacterial spot of stone fruits and almond: its genomic and phenotypic characteristics in the X. arboricola species context |journal=Molecular Plant Pathology |date=September 2018 |volume=19 |issue=9 |pages=2053–2065 |doi=10.1111/mpp.12679}} Spots may form on the leaves and they can be mistaken for peach scab, which is caused by a fungus.

Symptoms

An irregular browning leaf margin which may or may not be bordered by a pale halo.{{Cite web |title=BACTERIAL LEAF SCORCH OF SHADE TREES |url=http://www.usna.usda.gov/Research/BacterialLeafScorch.html |url-status=dead |archive-url=https://web.archive.org/web/20090416040708/http://www.usna.usda.gov/Research/BacterialLeafScorch.html |archive-date=2009-04-16 |access-date=2009-04-29}}

File:2023-08-29 09 38 11 Pin Oak leaves showing symptoms of bacterial leaf scorch along Willis Drive in the Mountainview section of Ewing Township, Mercer County, New Jersey.jpg

Symptoms re-occur every year, spreading throughout the tree crown, eventually killing the host plant.

Vectors

Xylem-feeding leafhoppers can transmit the disease bacteria. In general, any xylem-feeding insect can transmit the disease.{{Cite journal |last1=Sicard |first1=Anne |last2=Saponari |first2=Maria |last3=Vanhove |first3=Mathieu |last4=Castillo |first4=Andreina I. |last5=Giampetruzzi |first5=Annalisa |last6=Loconsole |first6=Giuliana |last7=Saldarelli |first7=Pasquale |last8=Boscia |first8=Donato |last9=Neema |first9=Claire |last10=Almeida |first10=Rodrigo P. P. |year=2021 |title=Introduction and adaptation of an emerging pathogen to olive trees in Italy |journal=Microbial Genomics |volume=7 |issue=12 |pages=000735 |doi=10.1099/mgen.0.000735 |doi-access=free |issn=2057-5858 |pmc=8767334 |pmid=34904938}}

Treatment

There are no known effective treatments for BLS, consequently, removal of affected plants is recommended.

See also

References

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