Honeydew on Plants: What It Is, What Causes It, and How to Get Rid of It

Sticky, shiny leaves? Black sooty mold? You've got honeydew — the sugary excretion of sap-feeding insects like aphids, mealybugs, soft scale, and whiteflies. The honeydew itself doesn't hurt the plant, but the insects do, and the mold blocks photosynthesis. Here's how to break the cycle.

What Causes Honeydew?

Piercing-sucking insects tap into plant veins and excrete excess sugar as honeydew. It attracts ants (which "farm" the pests) and wasps. The real damage: weakened growth, curled leaves, and sooty mold fungus growing on the sticky film.

How to Remove Honeydew and the Pests Behind It

1. Blast with water: A strong hose spray knocks off many aphids and washes away honeydew.
2. Encourage predators: Ladybug larvae, lacewings, parasitic wasps — avoid broad-spectrum insecticides that kill them.
3. Use targeted sprays: Neem oil, insecticidal soap, or horticultural oil smother soft-bodied pests without harming most beneficials. Repeat weekly as needed.
4. Clean surfaces: On cars/furniture, use mild detergent or 2 tbsp vinegar per gallon of water.

Prevention

• Scout plants weekly — catch infestations early.
• Don't over-fertilize with nitrogen — it promotes soft, pest-attracting growth.
• Keep plants healthy; stressed plants are magnets for pests.

Honeydew is a symptom, not the disease. Treat the insects, and the stickiness disappears.