Eggplant Phomopsis Blight – Reasons For Eggplant Leaf Spot And Fruit Rot
By: Mary H. Dyer, Credentialed Garden Writer
When growing eggplants in the garden, it isn’t uncommon to have issues now and then. One of these may include phomopsis blight. What is phomopsis blight of eggplant? Eggplant leaf spot and fruit rot, caused by the fungus Phomopsis vexans, is a destructive fungal disease that affects primarily fruit, stems, and leaves. Read on for more information about blight in eggplants.
Symptoms of Eggplant Phomopsis Blight
On seedlings, phomopsis blight of eggplant causes dark brown lesions, just above the soil line. As the disease develops, the lesions turn gray and the stems eventually collapse and the plant dies.
Blight in eggplants on established plants is evidenced by gray or brown, oval or round spots on the leaves and stems. The center of the spots lighten in color, and you can see circles of small black, pimple-like dots that are actually the fruiting bodies, or spores.
On fruit, phomopsis blight of eggplant begins with pale, sunken spots that may eventually take over the entire fruit. Tiny, black spots are visible in abundance.
Causes of Eggplant Leaf Spot and Fruit Rot
The tiny black spores of phomopsis blight live in the soil and spread quickly by rain splashing and overhead irrigation. Phomopsis also spreads easily on contaminated equipment. The disease is particularly favored by hot, damp weather conditions. Optimum temperatures for spread of disease is 84 to 90 F. (29-32 C.).
Managing Blight in Eggplants
Destroy infected plant material and debris immediately to prevent spread. Never place infected plant matter in your compost pile.
Plant resistant eggplant varieties and disease-free seeds. Allow 24 to 36 inches (61-91.5 cm.) between plants to provide ample air circulation.
Water early in the day to allow foliage and fruit to dry before evening.
Rotate crops every three to four years.
Various fungicides may be helpful when used with the above methods of control. Spray at fruit set and repeat every 10 days to two weeks until the eggplants are nearly mature. Experts at your local cooperative extension office can advise you about the best products and specific uses for your area.
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What Are the Most Common Eggplant Pests?
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Eggplants are part of the same family — the nightshades or solanaceae — as tomatoes, peppers and potatoes and are affected by a number of the same pests. The most common of the eggplant pests are members of the beetle, bug and mite groups. These pests consume the leaves and suck the life-supporting sap from the plants. Eggplants are also susceptible to various bacterial and fungal diseases that cause wilting and rot. Growing vegetables in the garden provides fresh, healthy produce but requires knowledgeable pest and disease management for an abundant crop.
One of the most obvious of the eggplant pests is the leaf-eating Colorado potato beetle. This striped beetle and its larva consume the foliage of potatoes, peppers and tomatoes. Tiny spider mites are one group of eggplant pests that suck the juices of eggplants, weakening the plants. These pests are found on the undersides of the leaves. They are most active during the dry, hot spells towards the end of summer and can be discouraged by adequately watering the eggplants.
Flea beetles are group of small insects that are common pests of all of the solanaceae crops. They are especially damaging to eggplants, which they prefer. The larva feed on the developing roots, while the adults attack the above-ground portions of the plant. Eggplant lace bugs and tiny aphids are eggplant pests that have specialized mouth parts for penetrating the plants and sucking their juices. An infestation can weaken the plants, preventing blossoming or stunting growth.
Eggplants are also susceptible to bacterial and fungal diseases. Verticillium wilt is caused by a soil fungus and results in small, wilted plants that eventually die. Blossom end rot is another fungal disease that causes the ripening fruits to fall off. Eggplants are also prone to bacterial wilt, which kills most infected plants. Several kinds of blight affect developing fruits or the whole plant, eventually causing the loss of the fruits or the destruction of the entire plant.
To protect this warm weather crop, using collars and row covers can help prevent early infestations. Frequent inspections and the use of insecticidal soaps can lessen the impact of pests on mature plants. Rotating where eggplants are located in the garden from year to year also helps reduce eggplant pests and diseases. Using insect predators such as ladybugs to control mites and praying mantis for larger insects is a strategy employed by many gardeners. Successful pest management is a key step in ensuring a healthy crop of eggplant.
2. Cercospora Leaf Spot (Cercospora spp.)
This fungal disease affects the leaves and stems of eggplant the fruit remains unaffected. The first sign of this disease are small, circular yellow lesions on the foliage. Eventually the lesions develop soft, gray fuzz at the center with a dark-brown ring around the exterior. Sometimes concentric rings appear, hence the disease nickname “frog eyes.” In severe infestations, defoliation can occur, and fruit size and production is greatly reduced.
Cercospora leaf spot survives the winter in plant debris, and when spring arrives, the spores are spread by wind, rain, people and animals. To keep spores off plants, mulch newly planted seedlings with straw or hay to prevent infected soil from splashing onto the leaves.
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