HORTICULTURE

Detailed explanation-1: -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. Leaves may yellow and have a mottled green or yellow appearance, show mosaic (e.g. chlorotic spotting) and ringspots (chlorotic or necrotic rings).

Detailed explanation-2: -Some of the fungi associated with leaf spots are Alternaria, Ascochyta, Blumeriella, Cercospora, Colletotrichum, Entomosporium, Gnomonia, Guignardia, Mycosphaerella, Phyllosticta, Septoria, Tubakia, and Venturia. Common bacteria associated with leaf spots are Pseudomonas and Xanthomonas.

Detailed explanation-3: -A symptom is a change in plant growth or appearance that may indicate or describe a plant health problem. Examples of symptoms include yellowing, wilting, dieback, galls or blight.

Detailed explanation-4: -The majority of leaf spots are caused by fungi, but some are caused by bacteria. Some insects also cause damage that appears like a leaf spot disease. Leaf spots on trees are very common and generally do not require spraying. Leaf spot may result in some defoliation of a plant.