• Verticillium wilt is attributed to the fungi verticillium dahlia and verticillium albo-atrum in soil, according to the University of Minnesota Extension. Verticillium wilt affects many different trees, the silver maple among them. The fungi remain in soils indefinitely, making soil-borne diseases a serious problem.
  
  

Verticillium Wilt

• Naturally caused wounds in tree roots allow the verticillium in the soil access to the plant's water conducting tissues. Toxins from the verticillium invade the plant and travel by way of the tree spores. The tree produces a gum-like substance in response to the toxin to limit its movement. However, this reduces water flow from the roots, causing wilting branches and other external infestation symptoms. Isolating the verticillium is difficult because the external symptoms are not an indication of the primary location of the fungus.
  
  

Symptoms

• Although symptoms from verticillium wilt occur anytime during the growing season, the disease usually manifests itself in July and August. Cold weather occasionally increases the severity of verticillium wilt, especially during or after such conditions. Milder symptoms of infestation include browning of the leaves, dieback of shoots and branches, small, yellow foliage and slow growth. Also, unusually heavy seed crops and drooping branches indicate the presence of verticillium wilt. More severe or acute symptoms consist of curling leaves, unnatural red or yellow leaf color and wilting and branch dieback, along with partial defoliation. Verticillium wilt possesses the potential to kill the silver maple tree.
  
  

Silver Maple Tree

• The verticillium fungi travel through silver maples via the growth rings. The verticillium wilt disease goes into a type of remission when the fungi fail to transfer to the next season's new growth. The disease is then considered compartmentalized or contained in the older growth of the silver maple. Symptoms will occasionally recur when a new infection moves up from the roots. Cut down any silver maples that show general to severe symptoms of verticillium wilt, as they do not recover.