Why Are My Pepper Leaves Curling?

Pests: check under the leaves

Aphids are a common cause of curling. Extensive feeding by aphids causes leaves to curl downward and inward from the edges and can yellow them, and the damage shows up first on the newest, youngest leaves near the center of the plant. Turn leaves over and look for the small soft-bodied insects and the sticky honeydew they leave behind.

If you find aphids, a strong spray of water, insecticidal soap, or simply supporting natural predators like ladybugs often brings them down. The presence of insects underneath is what separates a pest problem from a physiological one.

Edema and environmental stress

Edema is a physiological disorder, not a disease or pest. It develops under very high humidity or overwatering, when roots take up water faster than the plant can use or transpire it; pressure builds in the leaf cells until they burst, leaving small translucent, fluid-filled blisters mostly on the undersides of older leaves that later scar tan and corky. Plants usually recover once humidity drops or watering is reduced.

Plain environmental stress causes curling too. Heat, drying wind, and swings between bone-dry and soaked soil can make pepper leaves roll or cup as the plant conserves moisture. Even, consistent watering and light afternoon shade during heat waves usually relax the leaves without any treatment.

Herbicide drift: the one to rule out

Herbicide drift produces a very distinctive kind of curling. Growth-regulator weed killers such as 2,4-D and dicamba can vaporize and drift from nearby lawns or fields, and University of Minnesota Extension notes they make leaves cup, curl, and grow in strange, distorted shapes, with new growth twisted, narrow, or strappy and smaller than normal.

The tell is that the damage concentrates on new growth and looks warped rather than eaten or blistered, and it often appears across several different plants at once. There's no cure; many plants grow out of mild exposure, but avoid spraying weed killers on windy days near the garden. If you suspect drift and it's severe or recurring, contact your local Extension office.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

• Missouri Botanical Garden - Oedema (Edema) — Describes edema as a physiological disorder in which, under very high humidity, roots take up water faster than the plant can use or transpire it, causing small translucent fluid-filled blisters on the undersides of mostly older leaves that later scar tan and corky and can cause leaves to shrivel or roll; plants usually recover when moved to lower humidity or when humidity/watering is reduced.
• University of Minnesota Extension - Noticing Herbicide Drift in Your Garden? — States that growth-regulator herbicides such as 2,4-D and dicamba can vaporize and drift from where they were applied and injure garden plants, causing leaves to cup, curl, and grow in strange, distorted shapes, with new growth twisted and smaller than normal.
• UC IPM (UC Agriculture & Natural Resources) - Green Peach Aphid on Peppers — States that extensive aphid feeding causes pepper plants to turn yellow and leaves to curl downward and inward from the edges, with damage most prominent on newer, younger leaves; aphids and their honeydew can be found on leaf undersides.

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