Fungal Diseases

• Cytospora canker fungus attacks a variety of trees, including evergreens and deciduous trees. Infected trees produce a sticky white sap as a response to this fungus.
  
  

Identification

• In addition to the white, sticky substance, leaves on trees infected by the fungus turn brown and fall off. As the disease continues, the fungus works its way around branches, girdling them, resulting in death. It starts on lower branches, appearing higher in the tree as the disease advances. Stressed trees in poor growing conditions show increased susceptibility to this disease.
  
  

Prevention/Solution

• Preventing canker involves a combination of strategies, including providing ideal growing conditions in well-draining soil with plenty of room for future growth. Promoting strong growth through mulching, watering and fertilizing according to recommendations for the particular tree also decrease the risk of disease. Pruning infected branches at least 4 inches below visible cankers helps control this disease. Fungicides provide little benefit.
  
  

Considerations

• Some insect pests cause similar symptoms. For example, spittlebugs create a frothy white substance to protect themselves from predators. These bugs do not prove fatal and generally require no treatment, according to the University of Texas.