Question
I have one tree dying with this fungus.  It is near two more mimosa trees that did not bloom well this summer but so far not losing their leaves.  What should we do with the two remaining trees cut down or wait and see what happens next year.  What about the flower garden under the infected tree?  
Does this fungus affect all nearby trees (we live in the mountains of Va)?

Answer
Fusarium wilt is a common and lethal disease of mimosa (Albizia julibrissin)1, also commonly known as silktree. In the United States this disease occurs in the east from New York southward and also in Louisiana, Arkansas and California. Fusarium wilt is caused by the fungus Fusarium oxysporum forma specialis perniciosum. This pathogen causes Fusarium wilt on Albizia species and also on tree-ofheaven (Ailanthus altissima). Fusarium oxysporum f. sp. perniciosum colonizes and clogs the tree's vascular (water-conducting# tissue, and interferes with the movement of plant sap. This results in relatively rapid tree death.

Fusarium wilt is a lethal disease for which there are no controls. However, most tree species are not susceptible to Fusarium oxysporum f. sp. perniciosum, so replacing diseased mimosa with a non-susceptible host tree #i.e. genera other than Albizia and Ailanthus# is the best option.

Since it only infects these tow tree species it will not spread to other trees or to the garden plants. I would cut the diseased dead tree and remove all the wood form the property #burn it if possible). The remaining trees I would fertilize with 10-10-10 fertilizer at the rate of 1 lb of fertilizer per inch of trunk diameter scattered around the tree and watered in good. Apply just before a rain storm and you will not need to water tit in. This will increase the overall health of the remaining trees and help the trees fight the wilt. I would fertilize now and again in the spring.