By: Shelley Pierce
There are vegetables in the garden that seem to be universally embraced and then there is okra. It seems to be one of those vegetables that you either love or love to hate. If you love okra, you grow it for culinary reasons (to add to gumbo and stews) or for aesthetic reasons (for its ornamental hibiscus-like flowers). However, there are times when even the most ardent lover of okra is left with a bad taste in their mouth – and that is when there is blight on okra plants in the garden. Just what is okra southern blight and how do you treat okra with southern blight? Let’s find out, shall we?
Southern blight in okra, caused by the fungus Sclerotium rolfsii, was discovered in 1892 by Peter Henry in his Florida tomato fields. Okra and tomatoes are not the only plants to be susceptible to this fungus. It actually throws a wide net, encompassing at least 500 species in 100 families with curcurbits, crucifers and legumes being its most common targets. Okra southern blight is most prevalent in the southern United states and tropical and subtropical regions.
Southern blight starts with the fungus Sclerotium rolfsii, which resides within dormant asexual reproductive structures known as sclerotium (seed-like bodies). These sclerotium are germinated under favorable weather conditions (think “warm and wet”). Sclerotium rolfsii then begins a feeding frenzy on decaying plant material. This fuels the production of a fungal mat composed of a mass of branching white threads (hyphae), referred to collectively as the mycelium.
This mycelial mat comes into contact with an okra plant and injects the chemical lectin into the stem, which helps the fungi attach and bind to its host. As it feeds on the okra, a mass of white hyphae is then produced around the base of the okra plant and on top of the soil over a period of 4-9 days. On the heels of this is the creation of white seed-like sclerotia, which turn a yellowish-brown color, resembling mustard seeds. The fungus then dies and the sclerotia lie in wait to be germinated the following growing season.
An okra with southern blight can be identified by the aforementioned white mycelial mat but also by other tell-tale signs including yellowing and wilting foliage as well as browning stems and branches.
The following tips on controlling blight on okra plants might prove useful:
Practice good garden sanitation. Keep your garden free of weeds and plant debris and decay.
Remove and destroy infected okra plant matter immediately (do not compost). If the sclerotia seed-bodies have set, you will need to clean them all up as well as remove the top few inches of soil in the affected area.
Avoid overwatering. When watering, try doing so early in the day and consider the use of drip irrigation to ensure you are only watering at the base of the okra plant. This helps to keep your foliage drier.
Use a fungicide. If you are not opposed to chemical solutions, you may want to consider a soil drench with the fungicide Terrachlor, which is available to home gardeners and is probably the most effective means of treating okra with southern blight.
This article was last updated on
Robert Westerfield, Extension Horticulturist
Okra is a Southern staple in the home garden and at the dinner table and can be grown throughout the state of Georgia. It is considered a warm season vegetable and is a member of the Mallow family, which includes plants such as cotton and hibiscus. This vegetable is both easy and fun to grow and can be used in many different culinary dishes and for dried flower arrangements.
Prior to planting, soak the okra seeds in water for 12 to 18 hours to soften its hard seed coat. Soaking aids moisture absorption and germination.
Plant okra in the spring or early summer once the threat of frost has passed. To prevent the seeds from rotting, the soil should have warmed to at least 65 degrees. Gardeners in cool regions may want to start okra seeds indoors in peat pots four to six weeks before the area's final frost date.
If buying okra plants, purchase those that are started in containers such as peat pots that can go into the ground. Disturbing okra's roots hampers growth.
Okra can grow from three to six feet tall. Choose a garden spot where its shade will not harm other sun loving plants. Sow the seeds one inch deep in rows that are three feet apart. The seeds generally germinate in two to 12 days. Okra will grow in many soil types, so mulch and fertilize as needed.
Once the plants start to grow, thin them so they are spaced 12 to 18 inches apart.
Okra thrives in the full, hot sun. Regular watering is needed and is particularly critical during flowering and pod development. During extended dry spells, a weekly deep soaking is beneficial.
Crop rotation and good soil management help control diseases. Okra is susceptible to wilt, root knot nematode and Southern stem blight. It is not unusual for okra to attract various beetles and worms. Watch regularly for infestations and treat appropriately.
The more serious okra disease pests include rootknot nematode, Southern stem blight and wilt. A combination of crop rotation and good soil management is important for controlling these diseases. Foliage blights may occur, but generally they do not reach a level that requires treatment. Blossom blight can be serious during persistent rainy periods.
Several okra varieties (cultivars) are available to home gardeners and differ in plant size and fruit characteristics. Most varieties produce spineless pods. Some suggested varieties are listed below.
|Annie Oakley II||hybrid||spineless||dark green pods||4.5-foot-tall plants|
|Burgundy||open pollinated||burgundy red pods||4-foot-tall plants|
|Cajun Delight||hybrid||spineless||dark green pods||4-foot-tall plants|
|Clemson Spineless||open pollinated||spineless||dark green pods||4- to 5-foot-tall plants|
Status and Revision History
Published on Aug 14, 2008
Published on May 13, 2011
Published with Full Review on Aug 01, 2014