Oak Leaf Spot Management: Sanitation, Watering, and Timely Fungicides

Yellowing + Tiny Black Spots = Fungal Leaf Spot

Your 3-year-old oak in the Northwest shows classic fungal leaf spot symptoms. The organisms overwinter in fallen leaves and twigs; spring rains splash spores onto new foliage.

Integrated Management

• Sanitation: Rake and destroy fallen leaves; prune dead twigs.
• Keep foliage dry: No overhead watering; use soaker hoses or water early morning.
• Improve air flow: Prune for openness.
• Fungicides (protectant only): Apply at bud break next spring (Bordeaux, Daconil, Dithane, Fore). Won’t cure existing spots.

Leaf spots are mainly aesthetic; the tree will survive with good culture.