Honeydew and sooty mold from sap-suckers

What's happening

That sticky shine is honeydew — the sugary waste excreted by mealybugs, aphids, or scale as they drain sap from the plant. A black, dusty film growing on top of it is sooty mold, a harmless fungus that feeds on the honeydew but blocks light from the leaves. The stickiness is the early warning that an infestation is underway somewhere on the plant.

How to fix it

Hunt down the source: check leaf joints, undersides, new growth, and the woody flower spurs for white fuzz (mealybugs), tiny brown bumps (scale), or clustered soft insects (aphids). Wipe the sticky honeydew and sooty mold off the leaves with a damp cloth, then treat the whole plant thoroughly with neem oil, coating both leaf surfaces and every crevice. Repeat the neem treatment weekly until the leaves stay clean and dry.

This is general guidance based on common symptoms; individual plants vary.