Diagnosing and Managing Cercospora Leaf Spot on Leyland Cypress

I have a 25-foot-tall Leyland cypress hedge planted on 4-foot centers. It was healthy until this summer, when needles began dying at one end. The damage starts at the bottom near the trunk and moves upward and outward, while the outermost needles stay green. What's causing this?

Identification: Cercospora Leaf Spot

This classic "upward and outward" pattern is characteristic of Cercospora leaf spot, a common fungal disease in Leyland cypress and cryptomeria, especially after a damp spring and early summer. Close planting and shade worsen it. Unlike cankers that kill individual limbs, leaf spot browns the interior while branch tips remain green.

Management Strategies

• Cultural practices: Avoid overhead irrigation; water at the base during drought.
• Diagnosis confirmation: Contact your local Extension office (1-800-ASKUGA-1) for sample submission guidelines.
• Fungicides: Copper fungicides or Bordeaux mixture may help, but improving air circulation and reducing moisture on foliage is more effective long-term.

Most trees will push new needles once conditions favoring the disease subside.

For more details, see:

• Diseases of Leyland Cypress
• Auburn University Cercospora Blight
• Leyland Cypress Diseases
• Six Leyland Cypress Diseases

Leyland cypress cercospora

Leyland cypress seridium canker