Ash/Hickory Leaf Spot: Fungal Disease Management and Tree Identification

8-year-old tree (ash or hickory) with marginal brown leaf spots with black borders after wet spring and summer pruning—fungal leaf spot complex, not pruning damage.

Leaf Spot Pathology

• Fungal pathogens (multiple species) overwinter in fallen leaves/twigs
• Wet spring = spore splash onto tender new leaves
• Pruning coincidence, not cause—timing matched infection window
• Black border = typical fungal margin

Management: Live With It

Leaf spots rarely kill established trees. Control after infection starts is minimal.

• Rake and destroy fallen leaves (removes inoculum)
• Prune dead twigs
• Avoid overhead watering, especially evening
• Improve air circulation
• Accept aesthetic damage—tree health unaffected

Tree ID: Ash vs. Hickory

Close-up of leaf attachment to twig confirms ID. Both get similar leaf spots; management identical.