Sunflower Black Stem Deposits: Diagnosis Needed

Multiple Possible Causes

Black deposits at sunflower leaf-stem junctions could indicate:

• Sunflower stem weevil frass (larval droppings)
• Phoma black stem fungal lesions
• Aphid honeydew + sooty mold
• Natural pigmentation on some cultivars

Next Steps

Since visual diagnosis is essential, clear photos of the deposits, stem cross-section, and whole plant are needed. Email to byrd58@bellsouth.net with subject "allexperts" for specific identification and treatment advice.

General Care Meanwhile

• Avoid overhead watering.
• Scout for insects on leaf undersides.
• Remove severely affected plants if spreading rapidly.

Accurate ID prevents unnecessary treatment or crop loss.