Appearance

• Powdery mildew begins with a few white patches on the upper side of the leaves of a lilac bush. Over time, the mildew can spread to cover leaves and stems and even flowers, leaving your lilac bush looking as though it has been sprinkled with talcum powder.
  
  

Issues

• Powdery mildew detracts from the beauty of a lilac bush. Infected leaves might twist or distort; they often drop early. Because the fungus is stealing nutrients from the bush, it has to work harder to produce enough energy to feed itself. This can cause a lilac to fail to thrive.
  
  

Solutions

• Powdery mildew is easier to prevent than eliminate. Place plants so air circulates around them and they receive plenty of sun. If your lilac bush is infected, apply a fungicide every seven days to bring the fungus under control. Removing infected and dropped leaves can help control the infection.