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Relatively recent studies by Turecheck et al. [5] have shown heat treatments to be successful in dealing with angular leaf spot. They found that the number of living Xanthomonas fragariae were reduced by a minimum of 10 5-10 6 CFU/ml after exposing infected plants to heat treatments of 44-48 o C for 2–4 hours. [11]
Xanthomonas campestris pv.vesicatoria is a bacterium that causes bacterial leaf spot (BLS) on peppers and tomatoes. It is a gram-negative and rod-shaped. [1] It causes symptoms throughout the above-ground portion of the plant including leaf spots, fruit spots and stem cankers.
Xanthomonas campestris pv. raphani is a gram-negative, obligate aerobic bacterium that like many other Xanthomonas spp. bacteria has been found associated with plants. This organism is closely related with Xanthomonas campestris pv. campestris, but causes a non-vascular leaf spot disease that is clearly distinct from black rot of brassicas.
Xanthomonas (from greek: xanthos – "yellow"; monas – "entity") is a genus of bacteria, many of which cause plant diseases. [1] There are at least 27 plant associated Xanthomonas spp., that all together infect at least 400 plant species. Different species typically have specific host and/or tissue range and colonization strategies.
Xanthomonas pv. raphani has been found to enter the plant through its stomata to cause infection of the tissue, or rather parenchyma. This results in bacterial spot on a wider range of hosts, which includes both crucifers and certain solanaceous plants. [1] [8] [9]
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. [1] It can be mistaken for ordinary leaf scorch caused by cultural practices such as over-fertilization.
A common sign that will distinguish this pathogen from Septoria nodorum is the lack of spores on the leaves, which appears as tiny black spots on the leaf surface with a Septoria infection. A cream to yellow colored bacterial ooze produced by BLS infected plant parts is also a distinguishing sign of the pathogen. [7]
Leaf spots are visible symptoms of virus infections on plants, and are referred to as systemic symptoms. [7] In systematic virus infections leaf spots caused by viruses show a loss of green colour in leaves, due to chlorosis which is a repression of chlorophyll development. [1]