What are the different diseases of the iris?

Irises are susceptible to many types of infection.

Iris flowers are perennial, meaning they come back every year and grow from bulbs or rhizomes, depending on the variety. While busy gardeners may appreciate the fact that flowers appear in the same place each season, it also means that different types of iris diseases and pests can also establish themselves. Some diseases of the iris are caused by different types of fungal infections, such as fusarium wilt. Other diseases are the result of insect activity causing eventual bacterial infections.

Bacterial soft rot and fungi can damage iris flowers.

When planting iris bulbs, it’s best to avoid spots that have had these flowers on them in recent years, unless the goal is to expand an existing, healthy flower bed. Many types of iris diseases can live in the soil for years, and new plants can easily become infected if exposed to them. Choosing the wrong area will likely result in plants wilting and dying soon after germination, although some may live long enough to bloom before succumbing.

Fusarium wilt is an example of a fungal infection that can infest flowers for many years once it penetrates the soil. This problem typically infects the plant’s roots first, causing dead brown spots that feel sunken and are soft to the touch. The first visible symptom may be stubby, yellow leaves; soon after removing these leaves the plant will die.

Another iris disease caused by a fungus is mustard seed fungus, also known as crown rot and southern rust. Plants develop a brown slime that covers the base of the flowers and leaves and can spread along the plant, killing the healthy and unhealthy parts of the plant. This often preys on the iris flowers native to the Pacific coast and the multicolored bearded irises. Mustard seed fungus can be effectively prevented, but if it becomes established, both plants and soil must be removed from the area to prevent it from spreading further.

See also  What are the most popular sheep breeds?

Some types of iris diseases are caused by insect activity. Bacterial soft rot is one such problem and it occurs when bacteria get into wounds on the plant that were caused by iris borer activity. The rhizome becomes infected along with the leaves, and the plant emits a foul odor, often for no apparent reason. A closer inspection will usually reveal the tiny holes left by the iris borer, and the only solution may be to dig up and discard the entire plant, especially the rhizome.

Bacterial spot is one of the iris diseases that is not necessarily fatal to the plant but can still cause significant damage. Large wet-looking spots appear on the leaves, first at the edges and then spreading towards the center and turning brown, eventually changing to white as the leaf dies. Strict sanitation can help control the spread of this infection, as can removing any infected leaves. Leaves should be completely removed from the area and should never end up in the compost pile or near the edges of the garden.

Leave a Comment