• Post oak is susceptible to a number of fungal diseases.Oak Tree image by kris from Fotolia.com
  
  Post oak (Quercus stellata), also known as iron oak, is a medium-sized tree from the beech family that grows abundantly in South Central and Southeastern United States prairies. The tree is slow-growing, drought-resistant and grows well in a variety of soils, including rocky and sandy soils. The wood of post oak is used extensively for making fence posts. There are different varieties of post oak with different leaf shapes and acorn size. According to the USDA Forest Service Silvics Manual, the post oak tree is susceptible to the same diseases and insects that infect and infest other oaks.
  
  

Texas Root Rot

• Texas root rot is a fungal disease caused by the soil-borne fungus Phymatotrichum ormnivorum. The disease commonly attacks the trees on the old farm fields. According to a May 2009 article by Mary W. Olson published by the University of Arizona, Texas root rot causes a sudden wilting and death of the tree especially during summer. During cooler season, the disease causes a slow decline in tree health. The dead and dying foliage remains attached to the tree and the roots of the tree are rotted. Occasionally the fungus produces a white or light tan spore mat on the soil surface near the tree. Texas root rot can be controlled with the use of chemicals that should be repeated every couple of years to prevent recurrence of disease.
  
  

Chestnut Blight

• Chestnut blight is a fungal disease caused by Cryphonectria parasitica. The fungus is spread by rain, wind, animals and bird, and infects trees through the wounds or cracks on the bark. The disease spreads rapidly and creates sunken cankers that girdle the stems and kill all growth above the canker, according to the Virginia Tech Department of Plant Pathology, Physiology, and Weed Science. Early symptoms of the disease include an appearance of swollen or sunken stem cankers. The sunken canker may be covered with loose ended bark. It is common to find insect webs under the loose bark. Despite extensive research, there still is no effective treatment of the disease. As noted by the Department of Forest Health Production, current research is attempting to create blight-resistant varieties of susceptible tree species and the development of a hypovirulent strain of the fungus.
  
  

Oak Wilt

• Post oak trees are susceptible to oak wilt caused by the fungus Ceratocystis fagacearum. Oak wilt is considered the most serious tree disease in the eastern United States and affects many oak varieties. The fungus spreads either through underground roots or is transported by land insects and causes gradual death of the tree. Earliest symptom include wilting and dying leaves on individual branches. Leaves are discolored from the margin to the base and fall from tree. The treatment of oak wilt is expensive, hence the Department of Forest Health Protection recommends treatment of only high value trees. Other trees should be removed from the property and destroyed.