Blackleaf
Chalara spp., Asterina spp., Diplotheca spp.
2 host plants · Fungal
Last updated
Leaves turn black or dark brown from sooty mold or fungal infection. Treat underlying pests or improve sanitation. You are most likely to notice symptoms during periods of active growth, particularly when moisture levels favor pathogen development. Early recognition is your best advantage: the sooner you identify the problem, the more effective your management options will be.
Start with cultural controls: remove infected tissue, improve drainage and air circulation, and keep foliage dry when possible. Blackleaf responds best to early intervention, so scout regularly during the growing season and act at the first sign of symptoms. Chemical controls exist for severe cases but work best as preventive treatments before infection takes hold.
Quick Reference
Management
Late spring through fall (May-October), peak mid-summer when conditions are warm and wet. Young foliage most susceptible.
Warm, wet conditions (18-25°C / 64-77°F); prolonged leaf wetness from rain or overhead watering. Conidia require moisture for germination and infection.
Cultural Controls
- Avoid overhead watering
- Remove infected leaves and stems
- Remove heavily infected branches
- Improve air circulation
- Clean up fallen leaves
Most problematic in wet years with frequent overhead watering or rain during growing season. Drip irrigation or ground-level watering reduces disease pressure.