Why Are My Aubergine Leaves Curling?

Spider mite

Two-spotted spider mite (Tetranychus urticae) is the most serious pest of aubergine in UK greenhouses and polytunnels. The mites are too small to see with the naked eye but their damage is distinctive: a pale, bronze, mottled stippling on the upper leaf surface, caused by the mites piercing individual leaf cells and extracting the contents. The stippling begins on the older lower leaves and moves up the plant. In heavier infestations, fine silky webbing appears on the underside of leaves and between stems, the leaves curl and yellow, and eventually the plant begins to defoliate. Spider mites reproduce very rapidly in hot, dry conditions: a single female can lay up to 200 eggs and a generation completes in as little as 10 days at 30°C, meaning a light infestation can become severe within 2 to 3 weeks in a warm greenhouse.

What to do

• Inspect the underside of aubergine leaves every week from April, looking for pale stippling and any visible mites or eggs. Early detection before webbing appears is critical for effective control.
• Introduce the predatory mite Phytoseiulus persimilis as soon as the first mites are detected, or prophylactically in late April before populations build. This is the most effective control for aubergine under glass: Phytoseiulus actively hunts and devours spider mites and their eggs. Introduce alongside the banker plant system (beans or maize as alternative hosts for the predator) for sustained protection.
• Maintain humidity in the greenhouse: mist paths and staging in the morning to raise humidity levels. Spider mites reproduce significantly more slowly in humid conditions (above 60% relative humidity).
• Insecticidal soap or neem oil applied to all leaf surfaces, particularly the undersides, provides contact control. Multiple applications at 5 to 7 day intervals are needed to break the life cycle.

Aphids

Glasshouse mealybug aphid and peach-potato aphid (Myzus persicae) colonise aubergine growing tips and the underside of young leaves under glass. Feeding causes the young leaves to curl and distort, and the growing tip to become stunted. Aphids also excrete honeydew that coats leaves below the colony, promoting sooty mould.

What to do

• Inspect aubergine growing tips weekly. Remove colonies with a damp cloth or jet of water. Insecticidal soap is effective. The parasitoid wasp Aphidius colemani is an effective biological control for persistent aphid problems under glass.

Inconsistent watering

Aubergine requires consistent, even moisture: alternating between drought and waterlogging stresses the plant and causes the leaves to curl upward (drought) or droop and yellow from the base (overwatering). Inconsistent moisture during fruit development also causes blossom end rot: a sunken, dark patch at the blossom end of the fruit.

What to do

• Water aubergine regularly and consistently, keeping the compost evenly moist but not waterlogged. In grow bags or large pots, check moisture levels daily in hot weather: aubergine in containers dries out rapidly in summer. A drip irrigation system maintains more consistent moisture than hand watering.

Glasshouse whitefly

Glasshouse whitefly (Trialeurodes vaporariorum) affects aubergine, causing the leaves to yellow and droop as the nymphs feed on the underside. Adults disturbed from the plant fly up in a characteristic white cloud. Heavy infestations produce copious honeydew and associated sooty mould.

What to do

• Introduce the parasitoid wasp Encarsia formosa early in the season as a biological control. Yellow sticky traps catch adult whiteflies and reduce populations. Insecticidal soap provides contact control of nymphs when sprayed to the underside of leaves.

Frequently asked questions

Why are my aubergine leaves curling?

Aubergine leaves curl most commonly from two-spotted spider mite (Tetranychus urticae), aphids, or inconsistent watering. Spider mite is the most damaging and prevalent pest of aubergine grown under glass in the UK: it causes characteristic pale, bronze, mottled stippling on the leaves with fine webbing on the undersides, and the leaves curl, yellow, and drop as the infestation progresses. Aphids cluster on the growing tips and the underside of young leaves, causing the leaves to curl and distort around the feeding colonies. Inconsistent watering (alternating between waterlogging and drought) causes the leaves to curl upward or downward and may result in blossom end rot on the fruit.

How do I grow aubergine in the UK?

Aubergine (Solanum melongena) is a sub-tropical plant that requires warm growing conditions: in the UK it is almost always grown under glass (in a greenhouse or polytunnel) rather than outdoors, except in the warmest sheltered positions in the south and west of England during exceptional summers. Start seeds indoors in late January to March at a minimum temperature of 21°C. Pot on into 20 to 25 centimetre containers or grow bags when plants reach 15 centimetres. Maintain minimum temperatures of 16°C at night and 21 to 25°C during the day. Feed weekly with a high-potassium tomato fertiliser once the first flowers open. Pinch out the growing tip when the plant reaches 30 to 40 centimetres to encourage bushy growth and good fruit set. Support the main stem as it grows. Pick aubergines while the skin is still shiny and before the seeds develop fully; overripe aubergines turn bitter.

How do I prevent spider mite on aubergine?

Preventing spider mite on aubergine under glass requires maintaining higher humidity levels than the hot, dry conditions in which mites thrive. Key prevention measures: mist the leaves with water in the morning regularly (not in the evening, which can promote fungal diseases); ensure good ventilation in the greenhouse to avoid stagnant, hot air pockets; introduce the predatory mite Phytoseiulus persimilis early in the season before mite populations establish, as a preventive biological control rather than a curative one; inspect the underside of leaves weekly from April for the earliest signs of mite damage (pale stippling without visible webbing is the earliest stage); and avoid the very high temperatures (above 30°C) that dramatically accelerate spider mite reproduction. Biological control with Phytoseiulus persimilis is the most effective approach for aubergine under glass and avoids the need for repeated insecticide applications.

Why are my aubergine leaves turning yellow?

Aubergine leaves turn yellow for several reasons, the most common being: spider mite infestation (bronze-yellow stippling starting on older leaves); overwatering or waterlogging (uniform yellowing starting on lower leaves); magnesium or nitrogen deficiency (interveinal yellowing in the case of magnesium, overall pale yellowing for nitrogen); or natural ageing of the oldest lower leaves as the plant grows taller (normal). In the UK, the most common cause is spider mite, which causes a characteristic bronzed yellowing rather than a clean, uniform yellow. Check the underside of yellowing leaves carefully: visible webbing and tiny moving specks confirm spider mite. Yellow leaves caused by overwatering are typically limp and may have soft, rotting areas at the base of the stem. Deficiency symptoms appear on leaves in the middle of the plant rather than the oldest lower leaves.