Okra is susceptible to root knot nematodes. Have you googled to see a photo of okra roots showing root knot nematode damage? If your roots look like those in the photo, you will know for sure that nematodes are the problem. In general, root knot nematode damage shows up on roots as enlarged, distorted roots with nodules on them.

Other common okra problems include fusarian wilt, cotton root rot, southern blight, and certain blossom & fruit blights and leaf spots.

If root knot nematodes are the problem, there are many methods you can use to try to control the number of nematodes in your soil, but there is no way to completely eliminate them. Root knot nematodes are most often a problem in sandy and sandy loam soils......the higher the percentage of sand in the soil, the greater the likelihood of a nematode infestation.

The two methods most commonly used are soil solarization and fallowing the soil in the summer.

With soil solarization, you remove and destroy (do not compost) all current okra root debris that might be nematode infected. Then, till the soil and cover it with a thick, clear plastic. Keep the soil covered for a minimum of six weeks. Soil solarization is MOST effective when used during the hottest summer months, but is still somewhat effective when used during cooler weather.

To fallow the soil, you can't use the soil for that growing season. You till up the soil and keep it as dry as possible, taking care to see it receives no moisture other than what is naturally falling from the sky. You have to till the soil every week or two to keep it dry and to expose any nematodes in the soil to the heat and sun. Keep all the weeds out, also, as they can serve as host plants for the nematodes. The hotter and drier you keep the soil while fallowing it, the better.

You also can combat nematodes by increasing the amount of organic material in your soil by adding compost, composted animal manures, shredded autumn leaves, mushroom compost, finely shredded pine bark mulch, humus, partially decomposed straw, etc. The use of organic fertilizers instead of chemical fertilizers is helpful, too, as some chemical fertilizers can impede the growth of helpful microorganisms in the soil. These microorganisms can help control the population of root knot nematodes.

Keep in mind that peppers and tomatoes are also very susceptible to root-knot nematodes, so if they are part of your yearly crop rotation, they may be helping to keep the nematodes alive in the soil. Because you can buy and plant peppers and tomatoes that are resistant to root-knot nematodes, it is possible to successfully raise these crops in rotation with okra. Even though the peppers and tomatoes may resist the nematodes enough to survive them, they may be encouraging the survival of the nematode population, which later attacks okra grown in the same spot the following year.

Finally, some people use fall, winter and spring cover crops to combat nematodes. In some research studies, certain cover crops have been shown to decrease the amount of nematodes in the soil.

Dawn

THanks Dawn, knew I could count on you. You described the roots exactly--enlarged distorted roots with nodules. But here in eastern Ok we have loamy clay with a great deal of organic matter--no sand, and no chemical fertilizers. And I am only using a two year rotation if you factor in peppers and tomatoes. I will google nematodes to be sure, but I think that I will solarize the soil despite the fact that it is late in the season. And we will burn our okra after digging it up. Dorothy

Dorothy,

I was afraid you were going to tell me that you had rich, loamy 'eastern Oklahoma' soil....and you did! I have to confess that it leaves me feeling baffled! Based on everything I know about nematodes, including some first-hand experience with them in my parents' garden in Texas, I know that they are a severe problem in sandy soil. Back in 'the olden days' when I was a kid, you could fumigate your soil chemically and it would kill the nematodes. However, I don't think any chemical fumigants are available to home gardeners these days because they are just too deadly and kill EVERYTHING in the soil including all the microorganisms and earthworms. I think some chemical fumigants are still used, especially in Florida, by commercial growers.

And, I think I used the wrong term to describe plants that I said were 'resistant' to nematodes. That is how they were described when I was younger, but the terminology has been revised to "tolerant of" nematodes. It is a small technicality, but apparently the word 'tolerant' does not imply the plants could completely resist nematodes, and the word 'resistant' might imply that. Even tolerant plants often succumb to nematode damage, although they might last 1, 2 or 3 weeks longer than plants that are not tolerant.

So, how do we arrive at a logical reason for the presence of nematodes in your soil?

First, I would do a jar test and try to determine if there is a % of your soil that is sand. If so, that could explain the presence of the nematodes. However, unless there is a fairly high % of sand, the organic material in your soil OUGHT to counteract the sand content. If you've never done a jar test, let me know and I'll describe how to do it. When we first moved here, I used a jar test to help me determine what the clay content of our soil was. I discovered, through the use of several jar tests, that I had widely differing amounts of clay in different locations. On our property, heavy, dense red clay devoid of organic material predominates, but I also have some soil that is best described as sandy-clayey soil and silty-clayey, and one area that is almost pure sand, yet another one that is almost pure silt. In all cases, though, the basic solution is the same.....the addition of tons of organic material.

Secondly, it might not hurt to read up a little on cotton root rot. We have cotton root rot in the heaviest clay soil on our property, which used to be part of a farm....on which cotton was once grown. When I began losing plants to CRR, I knew what it was immediately because CRR is a huge problem in Texas, where I grew up. Cotton Root Rot affects thousands of plants and it also causes sudden death. If your okra plants were being affected by CRR, they would die very suddenly and often the 'death' moves up a row plant by plant. However, with CRR, when you pull up the roots or dig around in the soil near the roots, you often find a stringy, fibrous mat that looks sort of like the decomposed remains of very old carpet. That mass is a key sympton to watch for if you suspect CRR. Okra and plants related to it are very susceptible to CRR.

Since you are going to solarize during the cooler months, you might want to leave the plastic on for at least 12 weeks, and fall to winter may be better than winter to spring, because the degree of moisture received in eastern Oklahoma can make solarizing harder in spring weather. Your high moisture and humidity levels in the spring could encourage fungii to grow in your soil underneath that plastic. I suspect the last thing you want to do is to encourage the growth of more fungii.

Third, nematodes are a popular discussion topic on the Tomato Forum because they are such a problem for tomato growers. If you have time, you might want to go to the Tomato Forum and do a search for 'nematodes'. There are several threads there that have a LOT of good info on nematodes, including ways for home gardeners to combat them.

Fourth, if you are growing the standard commercial varieties of okra, you might want to try a couple of heirloom varieties to see if you can find one with better nematode tolerance. Baker Creek Heirloom Seeds (www.rareseeds.com) and Seed Savers Exchange (www.seedsavers.org) both offer heirloom okra varieties.

Hope this info helps.

Dawn (who grows okra primarily to entertain the deer, because they love it so very much, and I cannot keep them out of it!)

A lot to think about. I dug a plant and didn't find the old carpet mess. And the plants didn't die suddenly--never have--but a few scattered plants in the row will start losing lower leaves as they turn yellow, then brown until the stalk is bare over a period of a couple weeks, then more and more plants will follow the same pattern until they are all dead. And our garden is in a place that never saw cotton, but only cattle before we made it a garden. So I am going to plant the okra in a part of the garden where it has never been and solarize that row just to be safe, And the same thing with tomatoes as I lost several this year also. I wondered if this problem was related to the very wet spring and early summer that we had. Dorothy

Dorothy,

With the kind of rains we had in portions of Oklahoma this year, I think that excess moisture absolutely played a role in everything.....both good and bad....that happened in our gardens this year.

Excess moisture causes so many problems for plants, and especially for tomato plants because they are hyper-sensitive to waterlogged soil. Water-logged roots can't take up oxygen; excess water leaches nutrients from the soil; there is a a proliferation of fungal and bacterial diseases when there is high soil moisture and high humidity; and, of course, nematodes themselves move around better in wet soil because they actually move through the moisture that clings to grains of soil. Okra can handle waterlogged soil up to a point, and probably can handle it better than tomato plants, but there was just so much water this year that it probably played a role in your okra problems as well.

I hope solarizing the soil solves your nematode problem. If it doesn't, another thing to think about is that you can apply "beneficial nematodes" to your soil in the spring. They are expensive, but I think you would only have to apply them once. The beneficial nematodes eat the "bad" nematodes that are harmful to plant life.

Dawn

Thanks Dawn for all the info. We used to have deer problems, but our current dog pretty much keeps them run away from the garden. Have you ever used human hair and bloodmeal spread around or hanging in panty-hose packets on the plants you want to protect from deer? Have to keep the dogs away from bloodmeal though. Dial soap is suppossed to repel them too. Deer, not dogs.

Dorothy,

I have tried everything EXCEPT raising the height of my welded-wire garden fence from 4' to 8' feet, which is probably going to be my only solution.

I have had SOME luck with hanging Dial and Irish Spring soap from the top of the fence line. Of course, this 'unique' practice 'caused some of my neighbors to think I had lost my mind. (smile)

I have had some luck with running surveyor's tape around the top of the 6' tall fence posts. I think it 'tricks' the deer into thinking my 4' tall fence is 6' tall, and I also think that loose ends of surveyor's tape that I leave to flutter in the wind might help scare off the deer. Eventually, though, a bold deer jumps the fence, breaks the surveyor's tape, and then the deer get to feast in the garden every night.

I have had some luck with blood meal, but it also attracts undesirable animals--it took me a while to figure out that buzzards were circling in the air over my garden day after day because they were smelling the blood meal. (Bone meal attracts undesirable beasts too.)

I have had some luck scattering human hair (and dog hair pulled out of the dog brush), but the hungrier the deer get, the less this seems to work.

I have dogs, but can't let them run loose or leave them inside the garden fence at night because we have so many coyotes (including one who is HUGE and looks like a timber wolf and which has taken out at least 4 of our neighbors' cats and dogs in the last year) and the occasional black panther or the occasional cougar (DS and I have each had one close encounter---he with the panther, me with the cougar).

Because our property is only a half-mile or so from the Red River, we have all kinds of deer, including a herd of 6 to 8 that pretty much lives on the back part of our property (where it is densely wooded) year-round.

And, because I hate to see the deer starve, I put out deer corn for them in the winter months, although I put it far away from the garden. If I don't put out deer corn, though, they come and eat my evergreen shrubs and rye grass all winter long. And, if I forget to feed them, they come closer and closer to the house and stand and wait for me to feed them. So, if I could be cold-hearted and ignore them in the winter, they might go far, far away, but I just am too much of a softy to do that.

I think this winter we will double the height of the garden fence to 8'. I don't think anything else is going to protect the garden well enough.

After more or less successfully ridding the 'yard' of armadillos, possums and skunks, I am still at war with the deer, raccoons, and poisonous snakes. If it is not one thing, it is another!

Dawn

Here in Strawberry Land, 8 foot fences are a common sight. The commercial growers use 8 foot fences in conjunction with 12-15 foot wide,6-8 foot high dozer piles to keep deer out of 10 acre berry patches. And every third year they doze and fence a new patch. That may be your best solution--albeit an expensive one. Dorothy