Grape Leaf Curl: Aphid, Scale, or Water Stress Diagnosis

Curling Grape Leaves: Insect Infestation Most Likely

Grape vine (Vitis spp.) leaves curling under almost always indicates sap-sucking insects on leaf undersides.

Top Suspects (Check Undersides!)

• Aphids: Clusters on new growth. Cause tight curling. Honeydew → ants/sooty mold.
• Scale: Immobile bumps on stems/veins. Soft scale = honeydew. Armored = no honeydew.
• Mealybugs: Cottony clusters in leaf axils, on veins.

Treatment: Neem Oil (Organic, Edible-Safe)

1. Spray THOROUGHLY, especially leaf undersides and clusters.
2. Repeat weekly × 3–4 treatments.
3. Grapes edible 2 days after spray.
4. Acts as insecticide, miticide, fungicide, anti-feedant.

Alternative: Water Stress

If NO insects found: Deep water stress causes leaf curling (rolling to reduce transpiration). Water deeply, mulch, monitor.

90% of grape leaf curl = aphids. Flip a leaf. You'll likely see them.