Azalea: Botrytis petal blight

Biology

Botrytis petal blight is a fungal disease typically found in early spring. Symptoms of infection include brown, water-soaked spots on the leaves, and masses of gray-brown spores which form on infected tissues. Botrytis petal blight often occurs after the plant is injured or stressed.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Good air circulation is essential. Space plantings to reduce humidity and allow good air flow.
• Avoid overhead watering.
• Prune out infected tissue, making cuts into healthy wood and disinfecting pruning tools between cuts.
• Clean up and destroy any diseased material beneath plants.
• Remove faded flowers and yellow leaves from plants.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

Application interval varies by label. Best when used with cultural controls. Copper and chlorothalonil products may discolor blooms.

Approved Pesticides

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

• Bonide Copper Fungicide Spray or Dust RTU [Organic]
  Active ingredient: basic copper sulfate [EPA registration number: 4-58]
• Bonide Fung-onil Multi-Purpose Fungicide Concentrate
  Active ingredient: chlorothalonil [EPA registration number: 60063-9-4]
• Captan 50% WP Fruit and Ornamental
  Active ingredient: captan [EPA registration number: 4-459]
• GardenTech Daconil Fungicide Concentrate
  Active ingredient: chlorothalonil [EPA registration number: 67572-82-71004]
• Ortho Max Garden Disease Control Concentrate
  Active ingredient: chlorothalonil [EPA registration number: 239-2522]
• Spectracide IMMUNOX Multi-Purpose Fungicide Spray Concentrate
  Active ingredient: myclobutanil [EPA registration number: 9688-123-8845]
• This list may not include all products registered for this use.