Vascular Disease of Plants

any one of several diseases characterized by the loss of turgor in an entire plant or in certain parts of a plant as a result of functional disturbances of the vascular system.

Plants growing in soil with a low water content may develop vascular diseases. Other causes of vascular diseases include the disruption of the activity of the root system and the blocking of the vascular system with the mycelium of phytopathogenic fungi or accumulations of phytopathogenic bacteria. Other contributing factors may be the toxic action of parasites on the tissues of the plant-host and the formation in the vessels of tyloses (protoplastic swellings of the parenchymatous cells of xylem, which grow into the vessels).

The most common vascular diseases of plants are tracheomy-coses and tracheobacterioses. Tracheomycoses are a group of diseases caused by pathogenic fungi. They include mal secco, Dutch elm disease, and fusarium wilt and verticilliosis in cotton and many other plants. Tracheobacterioses are caused by phytopathogenic bacteria. They include bacterial wilt in Solanaceae, bacterial cancer in tomatoes, and ring rot in potatoes. Transverse and longitudinal sections of the tissues of a diseased plant clearly show a darkening of plant vessels.

Control measures include the destruction of plant remains, the selection of resistant varieties, and the implementation of agrotechnical measures that increase plant resistance to vascular diseases.