Eggplant, aubergine or brinjal, whatever you would like to call them, this vegetable has probably made an appearance on your plate and is definitely worth growing in your garden or on your smallholding.

The plant, Solanum melongena, is originally from India, but has spread to the rest of the world after it was domesticated from the wild nightshade or bitter apple.

These vegetables provide a good quantity of fibre, vitamins and minerals with few calories, making it nutritional and healthy.

Climatic and soil requirements

Eggplants can be cultivated in a variety of climates in open fields and tunnels. It is a warm season crop, but can withstand some cool weather. The temperature differences cannot be too extreme as it leads to a lower yield and a lower quality of fruits.

The minimum temperature it can handle is 10 °C, and the maximum is 34 °C. The ideal temperatures are between 26 and 29 °C.

Eggplants can be cultivated in open fields with irrigation. (Source: Pixabay)

It requires well-drained loam to sandy loam soils but can adapt to most soil types.

The vegetable needs a pH of 5,5 to 6,5.

Uses

Eggplants have many culinary uses. It can be boiled, grilled, stuffed, sauteed, roasted, or skewered. The vegetable can be served in stews, soups, stir fries or curries.

Be sure to only eat cooked eggplant, because when they are raw, they contain a chemical that can cause an upset stomach.

Soil preparation

To prepare soil, start with mixing in the residue from the previous crop. Use a disc cultivation to improve the aeration of the soil and distribute the organic matter throughout the seedbed. Soil preparation should be aimed at improving the drainage of the soil and reduce compaction.

This variety of eggplant produces lovely purple flowers. (Source: Pixabay)

Soil preparation needs to be done between 200 and 400 mm deep as this is where most of the roots grow. Create ridges in the seedbed, approximately 600 mm wide.

Planting

When cultivating an eggplant crop, the seeds are germinated in seed trays and the seedlings are then transplanted. Mulch, or black plastic, is placed around seedlings prevent them from drying out. Space plants 30 to 40 cm apart, planting them in the middle of the ridges.

Use stakes to keep the plants upright and reduce fruit rot.

Fertilisation

When fertilising the vegetables, 22 to 45 kg/ha nitrogen (N) can be applied, as well as 90 to 134 kg/ha of phosphorus (P) and potassium (K). This is usually broadcasted during soil preparation.

The unripen fruit of the eggplant. (Source: Pixabay)

To meet the plant’s total need of approximately 168 to 224 kg/ha of nitrogen per season, a weekly dose of 2,3 to 4,5 kg is applied until the flowering stage. During this period, 7 to 11 kg is applied, and 5 to 7 kg when fruiting. Soluble fertiliser is usually applied with water through the irrigation system.

Irrigation

As with most crops, too much or too little water can have devastating repercussions. These plants can tolerate both drought and excess rain, but not for extended periods.

Irrigation needs to be monitored. When irrigating, ensure that the water penetrates the soil deeply and thoroughly. You may need to irrigate more or less often, depending on hot conditions or wet, cooler weather.

These purple brinjals are almost ready to be harvested. (Source: Pixabay)

A preferred method of irrigation is either drip or flood irrigation as this helps prevent foliar disease.

Take care to provide enough water when plants are flowering, developing fruit and growing fruit.

Harvesting

When fruits show a glossy skin and has a size that is market ready, it is time to harvest. This usually occurs 15 to 35 days after flowering. The stem will harden and you will need a sharp knife to cut off the fruits.

If you planted a cultivar that has elongated fruit, it may take longer to ripen.

Remove fruit often to encourage fruit set. Fruit that are left too long on the plant become pithy and bitter. The harvested fruit should be washed and packed carefully.

Pest and disease control

Remember that any herbicides, inseticides and fungicides should only be used as indicated on the label.

Eggplants are harvested by hand. Make sure you do not bruise or damage the fruits. (Source: Zen Chung on Pexels)

Insects

Insects that attack eggplants:

  • Spider mites (Tetranychus spp.)
  • Green peach aphids (Myzus persicae)
  • Lygus (Lygus spp.)
  • Flea beetles (Chrysomelidae)
  • Wireworms (Elateridae).

The most dangerous of these are spider mites. Take care to treat the plants for spider mites as soon as the temperature rises.

Young plants are most susceptible to flea beetles.

When your eggplants are flowering, monitor the fields for lygus. It feeds on the flowers and causes flower drop. The root-knot nematodes (Meloidogyne spp.) lead to leaf wilt and yellowing.

Diseases

Leaf spot and fruit rot

One of the diseases that eggplants are susceptible to is leaf spot, and another is fruit rot. Both are caused by Phomopsis vexans. Symptoms include circular, brownish spots over fruits and leaves. In some cases, symptoms are not present at the time of harvest, and only appear post-harvest.

In order to control them, practice crop rotation and field sanitation, especially when the disease is detected. You can also pick the infected fruits and burn them.

(Source: Zen Chung on Pexels)

Early blight

This disease is caused by Alternaria solani, and is seen as collar rot in seedlings. The leaves are affected at all growth stages and fruits can drop. When plants are under stress, they are more vulnerable to the fungus. It favours temperatures between 16 and 32 °C.

Through proper field sanitation and using disease free seed, the fungus can be controlled. If you use your own seed, ensure that it is heat and water treated.

Anthracnose fruit rot

It is caused by Colletotrichum melongenae. Symptoms appear as sunken spots and lesions on the fruit. When the temperature is between 13 and 35 °C, and humidity at 93% or higher, the fungus is most active.

Control measures to implement include crop rotation and certified disease-free seeds or resistant varieties. Infected crop residue should be destroyed.

Bacterial wilt

This wilt is caused by Verticillium albo-atrum and it affects the vascular system of the plants. This results in stunted growth, discolouration, and leaf drop. Plants eventually die. This fungus flourishes in temperatures between 13 and 30 °C.

There are different shapes, sizes and colours of eggfruit. (Source: Pixabay)

Tobacco ring spot virus (TRSV)

It is characterised by yellowing leaves and plants dying off. Practicing crop rotation can have positive effects in managing the disease. The dagger nematode (Xiphinema spp.) is usually responsible for transferring TRSV.

The information provided in this article is credited to the Agricultural Research Council Vegetable and Ornamental Plant Institute (ARC-VOPI). For more information, contact +27(0)12-841-9611 or visit http://www.arc.agric.za.