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Symptoms seen with this virus include leaf mosaic or mottling (Fig. 1), yellowing, ringspots, stunting, and leaf, [12] flower and fruit distortion. CMV also induces a type of symptom on leaves known as the "shoestring" effect on many host species. This effect causes young leaves to appear narrow and the entire plant to be stunted. [13]
Symptoms are typical of viral diseases. Papaya exhibits yellowing, leaf distortion, and severe mosaic. Oily or water-soaked spots and streaks appear on the trunk and petioles. The fruit will exhibit bumps and the classic "ringspot". A severe isolate of PRSV has also been shown to cause tissue necrosis. [8]
Citrus greening is distinguished by the common symptoms of yellowing of the veins and adjacent tissues (hence the "yellow dragon" name given by observing Chaozhou farmers as early as the 1870s [1]); followed by splotchy mottling of the entire leaf, premature defoliation, dieback of twigs, decay of feeder rootlets and lateral roots, and decline in vigor, ultimately followed by the death of the ...
The incubation period between infection and obvious symptoms is usually one year or more, depending on the response of the plant to both pathogen and environmental circumstances. [1] Flavescence dorée has the following symptoms: [1] leaves become yellow or red, depending on the variety; downward rolling of leaves; drying of stems and grapes
Fusarium wilt is a common vascular wilt fungal disease, exhibiting symptoms similar to Verticillium wilt. This disease has been investigated extensively since the early years of this century. The pathogen that causes Fusarium wilt is Fusarium oxysporum (F. oxysporum). [1] The species is further divided into formae speciales based on host plant.
The symptoms are a marked yellowing of the leaves, an upright appearance to the leaves, with severe cases resulting in early death of the plant. Tuber initiation and growth is affected. Many small tubers are formed, frequently misshaped. In some cases, the tubers seem to have lost sprouting inhibition and have begun sprouting before harvest.
Aster yellows is a chronic, systemic plant disease caused by several bacteria called phytoplasma. [1] The aster yellows phytoplasma (AYP) affects 300 species in 38 families of broad-leaf herbaceous plants, primarily in the aster family, and important cereal crops such as wheat and barley.
Jaundice, also known as icterus, is a yellowish or greenish pigmentation of the skin and sclera due to high bilirubin levels. [3] [6] Jaundice in adults is typically a sign indicating the presence of underlying diseases involving abnormal heme metabolism, liver dysfunction, or biliary-tract obstruction. [7]