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Colletotrichum lindemuthianum is a fungus which causes anthracnose, or black spot disease, of the common bean plant (Phaseolus vulgaris).It is considered a hemibiotrophic pathogen because it spends part of its infection cycle as a biotroph, living off of the host but not harming it, and the other part as a necrotroph, killing and obtaining nutrients from the host tissues.
Phyllosticta citricarpa is a plant pathogen, some strains of which cause a leaf condition called black spot on citrus plants. [2] As a result, such strains are subject to phytosanitary legislation in the European Union and the United States.
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]
The patterns may appear on a few or many leaves. Plants are infected by this virus at propagation using infected plant material. [4] Rose wilt – Rose wilt is a complex of viruses and is referred to as "dieback" in some areas. The disease can be spread by vectors such as aphids. Symptoms are variable and range from stunted growth to curled ...
Numerous spots develop on the lower leaves, petioles, and stems. The disease produces small black spots on the leaves which eventually turn the leaf yellow, resulting in chlorosis and eventually cell death. [2] Spots are usually worse on older leaves. Stem lesions are dark brown to black and may cut the stem all the way around its surface.
The black spots are circular with a perforated edge, and reach a diameter of 14 mm (1 ⁄ 2 inch). Badly affected plants, however, will not show the circular patterning, as they combine to cause a large, black mass. The common treatment of the disease is to remove the affected leaves and spray with antifungal solutions.
In warm temperatures (over 24 °C), the production of phaseolotoxin decreases and symptoms become less obvious. Phaseolotoxin is a toxin produced by Halo blight pathogen which causes systemic chlorosis. [1] Halo blight causes small water-soaked spots on leaves. These spot progressively turn dark brown and are surrounded by a wide greenish ...
Plants growing outside exposed to rain exhibit dark brown to black spots on their leaf surface. When the plants are exposed to a limited amount of water and moisture, they exhibit sunken in lesions on both the upper and lower leaf surface. These different spots and lesion types often aid in the identification of P. cichorii. Free moisture on ...