Most gardeners have experienced the disappointment of apparently thriving, healthy plants dropping dead, in some cases overnight, in other cases a gradual decline over several months. The usual cause of such problems is a variety of fungal root rot diseases that infect the roots or crown of the plant and destroy the plants ability to take up water and nutrients. Typical early symptoms are wilting of foliage, death of bottom leaves or whole branches as well as general yellowing.
Root rotting fungi Phytophthora, Armillaria, Fusarium and Pythium
Several genera of plant pathogenic fungi can cause such symptoms, including Phytophthora, Armillaria, Fusarium and Pythium. If you suspect a root rot problem it is a very good idea to identify the fungus involved as different treatment strategies need to be employed depending on the life cycle of the particular fungus involved. Once a problem occurs the affected plant will often have to be destroyed, however, a suitable strategy for control will stop the problem spreading to healthy plants in your garden. Good hygiene after use in the garden will always help prevent problems. Practices such as cleaning soil from digging tools and disposal of diseased plants in a timely fashion will help enormously. Fungicides containing potassium phosphonate are another treatment that can be used to stimulate the plant’s natural defence mechanisms of the plant. Ask at your local nursery.