Black Substance on Mandevilla Leaves: Mold, Fungus, or Bird Droppings?

Diagnosing Leaf Deposits on Mandevilla

Black/brown washable deposits on front-yard mandevillas could be:

1. Sooty mold (from insect honeydew).
2. Fungal spores.
3. Bird droppings.

Questions to Narrow It Down

• Location/climate?
• Does washing reveal leaf damage underneath?
• Is it sticky before washing?

Sticky = insect honeydew (scale, aphids, whiteflies). Treat insects; mold disappears. Non-sticky = fungal/bird. Photos help.