Southern wilt can affect a variety of plants, including geranium flowers. The disease is particularly fond of plants in a landscape setting, and can spread through air and water. Infected plants should be removed.
Southern wilt is a bacterial disease caused by Ralstonia solanacearum. The bacteria is encouraged by higher temperatures, typically thriving in temperatures between 85 and 95 degrees F.
As the name suggests, Southern wilt is common in the southeastern U.S. and results in the wilting of the leaves on geranium plants, beginning in older leaves and spreading to newer ones. The bacteria also causes the water-conducting tissue in a geranium’s stem to turn brown and the roots of the plant may appear rotten and brown.
If left untreated, Southern wilt will kill a plant. One infected plant can also spread the bacteria to other nearby plants, particularly if the irrigation system is set up to allow the water to be recycled among multiple plants.