Crepe Myrtle Yellow Leaf Drop: Cercospora Leaf Spot Management

Symptom Match

2-yr-old crepe myrtle: center leaves yellowing/dropping 2 weeks, worsening despite reduced watering. Key check: small black spots on yellow leaves?

If Spots Present = Cercospora Leaf Spot

• Common fungal disease (Cercospora lythracearum).
• Starts low/interior → moves up.
• Warm, humid weather favors.
• Causes premature defoliation but rarely kills.

Current Season: Sanitation Only

• Rake/destroy all fallen leaves (removes spores).
• Do not compost.
• Water at base only (no overhead).

Next Spring: Preventative Spray Program

1. Start: As new leaves emerge.
2. Products: Spectracide Immunox (myclobutanil) OR Fertilome Liquid Systemic Fungicide (propiconazole).
3. Schedule: Every 10–14 days × 4–5 applications (per label).
4. Coverage: Entire canopy, both leaf surfaces.

Cultural Suppression

• Full sun, good air flow (prune for openness).
• Mulch to reduce splash.
• Resistant cultivars: 'Natchez', 'Muskogee', 'Tuscarora', 'Acoma'.

Watering Note

Reducing water was correct if soil was soggy. But established crepe myrtles need deep weekly soak in heat. Check soil 6" down.