The mimosa tree, or Albizia julibrissin, is also known as the silk tree and is native to China. This tree was brought to the United States in 1745 as an ornamental species. It is popular today due to its fragrant pink pompom flowers. A mature tree can reach a height of 20 to 40 feet. The silk tree is considered an invasive plant in Florida. This plant adapts to numerous soil types, re-sprouts when cut back and is spread by seed. Fusarium wilt is a disease which attacks the mimosa tree, causing tree death.
The disease is found from New York and southward, as well as in Arkansas, California and Louisiana. Fusarium wilt is caused by a fungus known as fusarium oxysporum forma specialis perniciosum. The fungus will clog the vascular system tissue and interfere with sap movement. Once the tree is attacked by fusarium wilt, the disease moves quickly through its system and the tree dies rapidly.
Since the disease attacks the vascular system tissue of a tree the first symptoms will go unnoticed. The only way that you will see the early symptoms of fusarium wilt will be if you happen to cut a branch of the tree and notice the brown streaking that will be present on the interior of the branch.
The tree will show noticeable symptoms such as yellow, stunted and wilted leaves. This disease usually attacks the tree in early to midsummer, and as the disease progresses you will notice the branches that showed the yellow/wilted leaves will lose all of their leaves. This process will continue as the fusarium wilt spreads throughout the other branches of the tree.
The bark of the mimosa tree will eventually be affected as the disease spreads. The bark will begin to crack. Sometimes a white liquid will ooze from the cracks. The liquid will have a fermented odor.
Unfortunately, there is no way to control this disease. Once the tree dies you can plant another tree in that same spot. However, choose a species that is not susceptible to fusarium wilt as the fungus can still be present in the soil for up to two years. There are several mimosa cultivars that are not susceptible to this disease: Charlotte, Tryon and Union.