Eggplant (Solanum)

Plant Health Problems

Diseases caused by Fungi:

Verticillium wilt, Verticillium dahliae.
The first symptom of eggplants infected with wilt is stunted growth followed by the wilting of leaves during the heat of the day. These leaves recover as the day cools. When the first fruit is set, certain leaves exhibit angular interveinal chlorosis or yellowing. Often half of a leaf becomes yellow and wilted. Finally, these leaves wither and fall off. The diseased plant is usually stunted and heavily defoliated. The inside of the stem is discolored. Verticillium, the fungus which causes this disease, can be seedborne and may live in the soil for many years. The fungus attacks a great number of other plants, including potatoes, tomatoes, snapdragons, and maples.

The only way to totally avoid the disease is to use clean seed, and plant on soil with no history of Verticillium wilt. However, the use of black plastic mulch and soil compost amendment may reduce the damage done by this disease.

Phomopsis blight, Phomopsis vexans.
This disease shows as light-colored leaf spots, and as a light brown spot rot on the fruit. Young plants may be killed outright. Infected fruits may rot completely. The fungus which causes this disease is soil- and seedborne. The spread of the disease is favored by warm, wet weather.

Use clean, properly treated seed and a four-year crop rotation. The spread of this pathogen can be reduced through the use of mulch which reduces the amount of soil splashed onto fruit and foliage during rain.

Insect Problems:

Colorado potato beetle.
This beetle in both the larval and adult stages feeds upon eggplant. See Colorado Potato Beetle fact sheet.

Cutworms.
See Cutworm fact sheet.

Flea beetles.
The eggplant flea beetle, Eptrix fuscula, and the potato flea beetle, Epitrix cucumeris, feed on eggplant. See Flea Beetle fact sheet.

Hornworms.
The tobacco and the tomato hornworms both occur in Connecticut and occasionally feed upon eggplant.
The tobacco hornworm, Manduca quinquemaculata larvae and that of the tomato hornworm, often feed upon the leaves of flowering tobacco. When fully grown, this larva is about 4" long, green with oblique whitish bands along each side and a horn on the tail end of the body. The adult moth is similar to that of the tobacco worm except that the forewings have a mottled gray-brown, appearance, and are somewhat darker in color. The wing spread is between 4 and 5". Although these caterpillars become large and consume a substantial quantity of leaf material, they are rarely abundant enough to require more than handpicking in gardens. Their abundant natural enemies usually regulate the population. Among the compounds registered for control of this pest in Connecticut are Bacillus thuringiensis var. kurstaki (Bt) or rotenone, which must be used when larvae are still small. Handpicking is more effective in gardens when the larvae are larger and more obvious. Consult the label for dosage rates, safety precautions, and preharvest intervals. The tomato hornworm, Manduca quinquemaculata, often feeds upon the leaves of tomato. When fully grown, this larva is about 4" long, green with oblique whitish bands along each side and a horn on the tail end of the body. The adult moth is similar to that of the tobacco worm except that the forewings have a mottled gray-brown, appearance, and are somewhat darker in color. The wing spread is between 4 and 5". Although these caterpillars become large and consume a substantial quantity of leaf material, they are rarely abundant enough to require more than handpicking on tomato in gardens. They do not usually feed directly on the fruit, and their abundant natural enemies usually regulate the population. Among the compounds registered for control of this pest in Connecticut are Bacillus thuringiensis var. kurstaki (Bt) or rotenone, which must be used when larvae are still small. Handpicking is more effective in gardens when the larvae are larger and more obvious. Consult the label for dosage rates, safety precautions, and preharvest intervals.

Pepper maggot, Zonosemata electa.
These maggots may also feed in the fruits of eggplant. The maggots of these barred-wing flies infest the fruits of peppers, causing them to decay, and in eggplants, resulting in tunneling within the fruit. The eggs are deposited in late July and August in the wall of the fruit and often project into the interior cavity. They hatch in 10 days and feed inside the core until mature, a period varying from 12 to 22 days. They then make an exit, usually near the stem in peppers, and go into the ground and pupate 1 or 2" beneath the surface. There is one generation a year. The adult fly is light yellowish-brown in color, with three brown bands across each wing. The adults feed on nitrogenous materials (perhaps bird droppings) in trees near pepper or eggplant fields. Damaging infestations are patchy and sporadic in Connecticut, and limited to fruit developing during the brief period (2-3 weeks) when egg-laying occurs. The problem is not usually recognized by the gardener until it is too late for control.

Potato aphid, Macrosiphum euphorbiae.
This aphid sometimes feeds on eggplant. See Aphid fact sheet.