They can be difficult to grow without these ingredients.
Here is a troubleshooting list of possible eggplant problems with control and cure suggestions: (More eggplant growing success tips are at the bottom of this post.)
Eggplant Growing Problems and Solutions
• Seedlings are cut off near the soil surface. Cutworms are gray or brown grubs that hide in the soil by day and feed at night. Handpick grubs from the soil around plants. Keep the garden free of plant debris. Place a 3-inch cardboard collar around the seedlings stem and push it 1 inch into the soil.
• Leaves roll downward but there is no yellowing or stunting. Physiological leaf roll, not caused by pathogen; it may be a reaction to temperature or weather. Keep plants evenly watered. No action needed.
• Leaves deformed, curled, and discolored; plants are stunted. Aphids are small soft-bodied insects–green and gray–that cluster on undersides of leaves. Aphids leave behind a sticky excrement called honeydew; black sooty mold may grow on honeydew. Spray away aphids with a blast of water; use insecticidal soap; aluminum mulch will disorient aphids. Aphid predators include lacewing flies, ladybugs, and praying mantis.
• Leaves wilt, turn yellow, then brown. Whiteflies are tiny insects that will lift up in a cloud when an infected plant is disturbed. These insects suck juices from plants and weaken them. Spray with insecticidal soap. Trap whiteflies with Tanglefoot spread on a bright yellow card.
• Leaves appear scorched and wilted. Leafhoppers are green, brown, or yellow bugs ⅓-inch long with wedge-shaped wings. Leafhoppers suck juices from leaves and stems. Spray with insecticidal soap or dust with diatomaceous earth. Cover plants with floating row covers to exclude leafhoppers.
• Shoots are white or yellow stippled; thin, fine webbing appears on underside of leaves. Spider mites suck plant juices causing stippling. Spray with water or use insecticidal soap or rotenone.
• Tiny round, shot holes in leaves; lower leaves are affected more than top ones. Flea beetles are tiny black beetles that feed on leaves and jump when disturbed. Handpick beetles and destroy. Keep the garden free of plant debris. Cultivate the soil deeply to destroy larvae in early spring and interrupt the life cycle.
• Leaves are eaten and plants are partially defoliated. Blister beetles and tomato hornworms eat leaves. Handpick insects and destroy. Keep the garden weeds and debris. Cultivate in spring to kill larvae and interrupt the life cycle. Pick off beetles by hand. Spray or dust with Sevin or use a pyrethrum or rotenone spray.
• Leaves and shoots are stripped. Colorado potato beetle is a yellow beetle ⅓ inch long with black stripes and an orange head. Handpick off beetles. Keep the garden free of debris. Spray with a mixture of basil leaves and water.
• White, frothy foam on stems. Spittle bugs are green insects that can be found beneath the foam. Handpick and destroy. They do not cause significant damage and can be tolerated.
• Lower leaves wilt; leaves on one side of plant wilt; yellow patches on leaves. Fusarium wilt or eggplant yellows are a fungal disease which attacks plant roots and spreads into the plant’s vascular system. Plant in well-drained soil. Rotate crops. Remove and destroy infected plants; older plants may be harvested and then uprooted and thrown away.
• Lower leaves yellow and die; stem is discolored with brown streaks when the stem is split lengthwise; plants wilt and die. Verticillium wilt is caused by a soilborne fungus. Plant verticillium-resistant varieties. Rotate crops and avoid planting in soil previously planted with pepper, potato, tomato, or cucumber family members.
• Leaves are mottled and streaked yellow and green; leaves curl and crinkle. Mosaic virus has no cure. It is spread by beetles. Plant tobacco mosaic virus-resistant varieties. Destroy infected plants and keep weeds down that host cucumber beetles. Wash your hands if you are a smoker.
• Leaves turn yellow then brown; brown to nearly black spots appear on leaves and lower stem. Early blight is a fungal disease spread by heavy rainfall and warm temperatures. Keep weeds down in the garden area; they harbor fungal spores. Avoid overhead watering.
• Galls or knots on plant roots; plants wilt in dry weather; plants become stunted. Root knot nematodes are nearly microscopic, translucent worms that inject toxins and bacteria into plant roots. Plant resistant varieties labeled VFN varieties. Feed plants with fish emulsion which seems to counter nematode toxins. Rotate crops. Companion plant with marigolds.
• Leaves and stems have irregular greenish water-soaked spots; whitish-gray growth appears on the underside of leaves; fruit takes on a corrugated look. Late blight is a fungal disease brought on by a rainy period followed by heat and humidity. Keep the garden clean and free of weeds. Remove infected plants. Improve soil drainage.
• Plants have lush foliage do not fruit or have little fruit. The soil may be nitrogen rich and lack phosphorus. Add aged compost to the planting bed before planting and side dress plants with aged compost. If night temperatures are cool place a wire cage around eggplants and drape the cage with plastic at night. Increase pollination and fruit production by lightly tapping plants to make sure pollen is distributed.
• Blossoms fall without producing fruit. Blossoms may fall if the temperature drops much below 60°F or rises above 75°F. Plant early varieties or varieties recommended for your region. Plant in warmer weather.
• Plants do not grow, appear stunted; blossoms drop off; fruit does not develop. Temperatures are too cool, below 40°F. Set out the plants when the air temperature remains above 65°F, or protect plants with plastic jugs with the bottoms cut out or other protective devices. Plant when the weather is warmer. Plant varieties recommended for your region.
• Buds and blossoms have holes; young fruits may have holes or drop; mature fruit can become misshapen and blotchy. The pepper weevil is a dark beetle ⅛ inch long; the larva is a white, legless grub found inside fruit. Handpick weevils and grubs. Nightshade plants host the pepper weevil; destroy infested plants after harvest. Cultivate the soil to interrupt the pest’s life cycle.
• Fruit is normal-colored but small and flattened; there are few or no seed inside. Pollination was poor or incomplete. Plant when the weather has warmed and insects are active. Attract bees and other pollinators to the garden. Increase pollination and fruit production by lightly tapping plants to make sure pollen is distributed.
• White spots on fruit; leaf tips are distorted. Thrips are tiny insects, yellow, brown or black with fringed wings. They scrape plant tissue as they feed leaving a scar. Keep garden free of weeds. Spray with insecticidal soap or sprinkle diatomaceous earth on leaves.
• Sunken, water-soaked spots develop on blossom end of fruit; spots can turn black and mold may appear; patches may appear leathery. Blossom end rot is caused by irregular watering or the irregular uptake of water by plants; this can happen when temperatures rise above 90°F. Keep soil evenly moist; mulch around plants. The soil may have a calcium imbalance that inhibits the uptake of water; add limestone to the soil if the pH is below 6.0.
• Sunken water-soaked areas on fruit and stems; fruit may become watery and collapse. Anthracnose is a fungus disease that over-winters in infected seed and the soil. Destroy rotting fruit; keep fruit off soil. Spray or dust with a fixed copper- or sulfur-based fungicide every 7 days. Do not collect infected seed.
Eggplant Growing Success Tips:
Planting. Grow eggplant plant in full sun sheltered from the wind. Eggplant prefers well-drained soil rich in organic matter; add aged compost to each planting hole.
Plant time. Plant eggplant when the soil temperature is at least 60°F, not sooner than 2 weeks after the last frost in spring. To jump start the season, sow eggplant indoors 8 to 10 weeks before setting it into the garden.
Care. Eggplant is finicky; there’s no getting around it. Keep the soil evenly moist, not too wet. Do not let the soil try out. Grow eggplant in organically rich soil and side dress plants with aged compost or compost tea 2 or 3 times during the growing season. Eggplant demands warm temperatures in the 70°s and 80°s. Growing eggplant against a stake or in a small tomato cage will ensure it does not fall or break when fruit is set and ripening.
Harvest. Pick eggplant when it is one-half to one-third its full size at maturity; make sure you know the variety you are growing–a mature eggplant can be anywhere from 2 to 10 inches long. If you press the skin with your finger and the skin springs back, the fruit is ready for harvest. A fruit fast its peak will lose its shiny color.
More tips: How to Grow Eggplant.