Symptoms of Bacterial Plant Diseases

Although most of the diseases are caused by fungi in plants (almost 80%) but even then bacteria cause some of the most economically destructive diseases in plants. Most of the bacteria are saprophytic in plants and perform the useful task of clearing out of the dead organic matter and some also form root nodules in legumes. Yet the diseases can not be ignored. 

Bacterial diseases usually under moist and warm conditions hence they are more common in tropics on all kind of plants. But they can be highly destructive in all over under favorable conditions. Here is a list of important disease symptoms with some example.

Sr.#	Symptom	Causal Agents	Symptoms	Affected Plant Species and Additional Information
1	Leaf Spots and Lesions	Xanthomonas, Pseudomonas	Circular or irregular discolorations on leaves; can vary in size and shape.	Various plant species, such as tomatoes (Xanthomonas campestris pv. vesicatoria) and cucumbers (Pseudomonas syringae pv. lachrymans).
2	Bacterial Blights	Xanthomonas, Pseudomonas	Irregular dark lesions on leaves; often associated with water-soaked appearance.	Common in various crops, including beans, tomatoes, and peppers; bacterial blights affect leaves and may lead to defoliation.
3	Wilting and Yellowing	Ralstonia solanacearum	Generalized wilting, yellowing of leaves due to disruption of water transport.	Affects a multitude of crops, including potatoes, tomatoes, and bananas. The bacteria persist in soil, leading to long-term crop risk.
4	Stunted Growth	Agrobacterium tumefaciens	Inhibition of normal growth, often accompanied by abnormal development.	Affects dicotyledonous plants, leading to the formation of tumors or galls; commonly found in fruit trees and ornamental plants.
5	Water-Soaked Lesions	Erwinia species	Lesions with a moist appearance, resulting from breakdown of plant cells.	Affects a wide range of plants, including potatoes (Erwinia carotovora) and ornamentals. The bacteria thrive in humid conditions.
6	Gumming or Exudates	Xylella fastidiosa	Sticky substance on affected areas, plant's response to bacterial invasion.	Common in grapevines, citrus trees, and other woody plants; the exudates are the plant's attempt to block the pathogen's movement.
7	Vascular Discoloration	Xylella fastidiosa, Corynebacterium	Streaks or discoloration in plant's vascular bundles.	Affects grapevines, citrus trees, and various fruit and ornamental trees; disrupts water transport, leading to systemic symptoms.
8	Tumor or Gall Formation	Agrobacterium tumefaciens	Abnormal growths on roots, stems, or leaves, induced by bacterial genetic material.	Common in dicotyledonous flowering plants; Agrobacterium mediates the transfer of genes into the plant's genome.
9	Leaf Necrosis	Pseudomonas syringae, Xanthomonas	Browning or blackening of plant tissue, indicative of cell death.	Affects numerous plants, including tomatoes (Pseudomonas syringae) and stone fruits; leads to rapid tissue decay.
10	Abnormal Growth Patterns	Various bacteria	Twisted leaves, irregular stems, or abnormal branching due to hormonal disruption.	Found in a wide range of plants; symptoms are often associated with altered hormone levels, affecting plant development.
11	Seedborne Symptoms	Clavibacter michiganensis, Pseudomonas syringae	Discoloration or deformation of seeds, affecting seed quality.	Affects tomato plants and other seed-producing crops; contaminated seeds contribute to the spread of bacterial infections.
12	Foul Odors	Various bacteria	Unpleasant smells resulting from bacterial metabolism; not specific to particular pathogens.	Not plant-specific; applicable to various crops and plants; odors may indicate the presence of anaerobic bacteria in soil.
13	Secondary Infections	Various pathogens	Presence of additional symptoms not typical of bacterial infections, such as powdery mildew or rust.	Affects various plants depending on secondary pathogens involved; highlights the susceptibility of weakened plants to other diseases.
14	Discoloration of Shoot Tips	Erwinia species	Browning or blackening of growing tips, indicative of bacterial impact on active growth areas.	Affects a variety of plants, including ornamentals and fruit crops; visible symptoms on growing tips can indicate the onset of bacterial diseases.
15	Leaf Curling or Rolling	Xanthomonas species	Abnormal curling, folding, or rolling of leaves due to bacterial influence on leaf morphology.	Common in many plant species, including tomatoes and peppers; symptoms can vary based on bacterial strains and host plants.
16	Yellowing Patterns	Various bacterial strains	Distinctive yellowing patterns, specific to different bacterial species.	Affects a wide range of plants depending on bacterial strains; specific yellowing patterns can aid in bacterial identification.