Eggplant needs attention to grow successfully. It is sensitive to cold temperatures, needs fertile soil and does not tolerate water stress. Monitor eggplant daily for early signs of pests and diseases. Eggplant requires a long, warm growing season to produce substantial amounts of fruit.
Shrivelled and crumbling leaves indicate drought stress in eggplants. Cupped leaves are early signs of water stress. Consistent and adequate moisture is especially important in the seedling and fruit-set stages. When the soil is dry 1 inch below the surface, saturate the area until the soil is wet at least 6 inches deep. In the summer, mulch beneath the plant to conserve water.
Often confused with drought stress, symptoms of verticillium wilt include wilting, yellow leaves followed by stunting and plant death. Caused by soilborne fungi, verticillium wilt shuts down water conducting vessels. Visual indicators of verticillium wilt include a brown v-shaped pattern that is widest at the leaf margins. Verticillium wilt survives from season to season on infected crop residue and weed hosts. Dispose of infected plants and do not grow solanacious plants, such as eggplant, tomato and potato, in the plot for three years. There is no effective treatment for this disease.
Phytophthora blight infects eggplant's roots, stems, leaves and fruit. Leaf wilt, often the first sign of phytophthora blight, precedes sudden plant death just before the fruiting stage. Earlier, subtle signs of the disease include lesions on the stem at the soil level and small dark green spots on the leaves. Leaf spots lighten to a bleached colour as the disease progresses. This soilborne fungus is more prevalent on poorly drained soils. Prevent infection by planting on raised beds or on a ridge with well-draining soil. Dispose of infected plants and do not grow plants from the same family, such as eggplant, tomato and potato in the plot for three years. No effective treatment for this disease has been established.
Pests, such as flea beetles and the Colorado potato beetle, cause eggplant leaves to shrivel. Flea beetles, 1/8-inch long, black, shiny beetles, create small, shotgun-patterned holes in the leaves. Severe infestations cause the leaves to turn brown before the plant dies. Flea beetles overwinter in weeds and plant residue. Cover young eggplants with floating row covers, a thin fabric allows water and sunlight in, but provides a barrier from flea beetles. Colorado potato beetles, 1/2-inch long, brown-and-white striped beetles, migrate to areas where eggplant, tomatoes and potatoes have been grown in the past. They lay their eggs on the underside of the leaves. Hatching larvae devour the leaves. Prevent damage from Colorado potato beetles by rotating eggplant at least 200 yards away from the previous eggplant, potato or tomato crop. Physical barriers, such as straw mulch and trench traps, reduce infestation. Avoid applying pesticides that kill lady beetles, as these are natural predators of Colorado potato beetles.