A sticky honey-like substance secreted onto foliage by aphids, scale, and mealy bugs.
Merriam-Webster Online Dictionary
honeydew (noun)1.
a saccharine deposit secreted on the leaves of plants usually by aphids or scale insects or sometimes by a fungus
2.
- honeydew melon
Sweet Resin, Sticky Nectar, Glistening Sap, Sugary Secretion, Dewy Essence
