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''. It can be mistaken for ordinary ''

leaf scorch Leaf scorch (also called leaf burn, leaf wilt, and sun scorch) is defined as a browning of plant tissues, including leaf margins and tips, and yellowing or darkening of veins which may lead to eventual wilting and abscission of the leaf.

'' caused by cultural practices such as over-fertilization.

Hosts

BLS can be found on a wide variety of hosts, ranging from ornamental trees (

elm Elms are deciduous and semi-deciduous trees comprising the flowering plant genus ''Ulmus'' in the plant family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical-montane regions of North ...

maple ''Acer'' () is a genus of trees and shrubs commonly known as maples. The genus is placed in the family Sapindaceae.Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 nd more or less continuously updated since http ...

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

) and shrubs, to crop species including

blueberry Blueberries are a widely distributed and widespread group of perennial flowering plants with blue or purple berries. They are classified in the section ''Cyanococcus'' within the genus ''Vaccinium''. ''Vaccinium'' also includes cranberries, bi ...

and

almond The almond (''Prunus amygdalus'', syn. ''Prunus dulcis'') is a species of tree native to Iran and surrounding countries, including the Levant. The almond is also the name of the edible and widely cultivated seed of this tree. Within the genus ...

Bacterial spot of peppers and tomatoes

Bacterial spot of peppers and tomatoes is caused by the bacteria ''Xanthomonas campestris'' pv. ''vesicatoria''.

Bacterial spot of peaches

Bacterial spot of peaches is caused by the bacteria ''Xanthomonas campestris'' pv. ''pruni''. Spots may form on the leaves and they can be mistaken for ''peach scab'', which is caused by a fungus.

Bacterial spot of pecans

Symptoms

An irregular browning leaf margin which may or may not be bordered by a pale halo.http://www.usna.usda.gov/Research/BacterialLeafScorch.html Symptoms re-occur every year, spreading throughout the

tree crown The crown of a plant refers to the total of an individual plant's aboveground parts, including stems, leaves, and reproductive structures. A plant community canopy consists of one or more plant crowns growing in a given area. The crown of a wo ...

, eventually killing the host plant.

Vectors

Xylem-feeding

leafhopper A leafhopper is the common name for any species from the family Cicadellidae. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind legs are modified for jumping, and a ...

s can transmit the disease bacteria.

Treatment

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

References

External links

Bacterial tree pathogens and diseases Food plant pathogens and diseases Leaf diseases {{plant-disease-stub