Wilt Diseases OF Chrysanthemum

Disease Information

Wilt Diseases

Symptomsand damage

When fungi or bacteria enter the roots and stems of a plant and cause stunting, wilt and death by plugging the vascular system, this is called a "vascular wilt." Infected plants wilt and die. If you cut into the stem, the vascular tissues show discoloration as tan, reddish, or dark streaking. Several fungi and bacteria may cause vascular wilts in herbaceous plants.

Fungal Wilts
Fungal wilts are caused by species of Fusarium, Verticillium and Phytophthora. The fungus grows into the roots of a susceptible plant, and eventually grows up into the stem. If you cut into the stem, you can see a brown, olive green or sometimes reddish brown streaking in the vascular tissues just under the stem epidermis.

Fusarium wilt 

often attacks Astilbe, Dendranthema (garden chrysanthemum),Dicentra (bleeding-heart), Echinacea (cone flower), Lupinus (lupine), Nepeta(catnip), Ocimum (basil), and Sedum. 
Verticillium wilt often attacks Aconitum (Monkshood), Dahlia, Liatris(gayfeather), Paeonia (peony), Papaver (poppy), Phlox, Rudbeckia (black-eyed-Susan), and Salvia. 
Phytophthora often attacks Euphorbia (Spurge), Lavendula (lavender), Sedum, and Vinca.


Management

 Fusarium, which is usually highly host specific, the control can be a simple rotation away from the plant that was damaged. Verticillium has a broader host range and so presents a more difficult problem in selecting "non-susceptible" plants for rotation. Phytophthora is so strongly influenced by drainage that often construction of raised beds and incorporation of organic soil amendments to improve soil drainage will reduce disease and permit replanting with a susceptible crop.

Bacterial wilts

Bacterial wilts are much less common on herbaceous perennials than fungal wilts.

 Begonia are sometimes infected. They are usually introduced in infected plants and can be carried in/on infected seed. They seldom persist for longer than one growing season in soils in temperate regions. Bacterial wilts can be diagnosed by examination of the vascular tissues for bacterial streaming, and by isolation in culture.

The best solution for bacterial wilts is to remove infected plants.

 



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