I've not ever had the root knot nemetode but the usual recommendations for control when you do have them is to improve the health of your soil, by adding organic matter so populations of other wee critters that are antagonistic to those root knot nematodes work to control them. From what I have read about ClandoSan this is pretty much what it does in conjunction with other organic matter in the soil. An article from Mississippi State indicates it can take 4 or more weeks before you get control.

Gardens alive has specific beneficial nematodes for root knot damage. I haven't used it, I plan on using a more general beneficial nematode in my garden.

Here is a link that might be useful: Beneficial Sf Nematodes

Thanks, rj -
Good info - very much appreciated.

What beneficial nematode are you planning to use for a general application?

Does your soil have a specific problem you're trying to correct, or is the application primarily for prevention?

Robert

I just found out I have RKN- my winter squash roots are full of the knots. With the extreme drought here in Cent TX, I guess the parasites have more impact.
Besides Clandosan, which I haven't tried yet, I've read about Neem cakes (ground up neem seed, provides slow N release along with nematode protection) and the use of several cover crops (till into soil then plant vegies)- including Gaillardia pulchella or Indian Blanket- a common Tx wildflower. Burpee sells a "Nema-gone" French Marigold, purported to do the same thing. More info on all of these at the link below.
Let me know if you have any success- I've had my garden in the same spot for 25 years and am worried about having to find a new area!!

Here is a link that might be useful: Article on nematode control

driftwood gardener,

My client decided against the Clandosan treatment due to high cost, and lives on the coast where shrimp and crab shells are plentiful and free. I taught him how to compost with them. Nematodes under control now.

In my opinion, the article on nematode control (at the bottom) you included with your post, provides the cheapest and by far the best cure for root-knot (parasitic) nematodes - by increasing the chitin-eating microbes in soil. The exoskeleton of parasitic nematodes contains chitin. Microbes kill nematodes by eating their 'shells'.

My recommendation is to visit seafood suppliers in your area and speak with the Manager to ascertain possibility of obtaining shrimp and crab heads/shells that are very high in chitin content (uncooked is preferred, but cooked shells will work also, so also check with restaurant Managers too).

Pulverize/chop dry shells as finely as possible, then add to active/moist new compost (batch method). If you don't compost, add the shells directly into the bed soil where you plant veggies that are subject to the most parasitic nematode damage and keep the soil moist and covered 2" with shredded hay/leaves or grass clipping mulch.
You cannot add too much shell material.
The shells will decompose due to increase reproduction of chitin-loving microbes if sufficient moisture exists.

Other methods/products produce varying results at varying costs. Some plants produce substances that nematodes don't like much (I think 'repel' is too strong a word) and results are very localized and do almost nothing to actually reduce nematode populations.

If a new garden location is not a big production/hassle for you, that's by far the fastest, most effective method for plant production that is being damaged by nematode infestation - but that method ignores the nematodes in the infested soil. Nematodes are worms. They move toward food.
Crop rotation and cover crops are a very good idea too.

If you establish a new garden area, incorporate (as amendment) LOTS of quality organic material FIRST. Double-dig method is much better than tilling, unless the ground is hard and needs a tiller to break up the surface level.

Do not compost the roots of nematode-infested plants unless you use the aerobic hot compost method; place chopped roots in the center; and ensure that your pile attains over 131F for 6 days minimum - and don't use the resulting compost until the center of a 2nd turn is below 105F (mesophilic microbes kill nematodes, not thermophilic)
And if you already compost with chitin, add some of that fresh compost to each new pile too.

Please let me know what you decide to do about your nematode problem, and how successful you are after fall garden production.

My hat's off to you, kimmsr - you were right on target.

Soilguy

Interesting. My county extension agent suggested I use solarization during the summer and planting Elbon rye during the winter. He also mentioned that you need to keep the area clear of any growing plants so that the nematodes have no where to reproduce. Elbon rye works as a trap plant. It keeps the nematodes from being able to finish their reproduction cycle and provides tons of biomass to the soil when tilled in.

Ext. Agent is correct, to a degree.

Solarization is not my first choice, since nematode-killing temps do not reach far enough depth in soil - but will kill some - however, the heat will also kill a lot of beneficial organisms too. Not a good trade-off in my opinion, although solarization is usually recommended for a garden along with adding large amounts of compost AFTER solarization - to replenish microbes and 'critters'.

Please understand, that I'm NOT referring to commercial "compost" or "humus" in plastic bags from a 'big box' store - but rather fresh, local, highly biologically active compost from a hot aerobic process.

Elbon (cereal) rye [not annual rye] can help. Theory is, the nematode juveniles which hatch inside the root, can't eat their way out, and are trapped.

Elbon rye can reduce root-knot nematode population, but is not a good choice for me in zone 9A, since my garden is active throughout the winter. And I don't need the organic rye as tillage, since I compost extensively and don't till my garden soil. If I were to leave a garden area fallow for a season, my choice in Texas is summer.

Keeping a garden area clear of any plants (just so nematodes have nowhere to reproduce) is counter-productive unless someone has sufficient land to lay it dry fallow.

Soilguy

Here is a link that might be useful: Arizona Edu. - Nematode Info

Thanks so much for posting this thread. I just discovered I have Root-Knot Nematodes in at least one of my raised beds.

My watermelons were dying and when I pulled them out, discovered the roots were covered with knots.

This was a brand new bed this year; filled with soil mixed with leaf mulch and compost harvested this Spring. The area where we built this bed was not planted the last two years...think it had some volunteer Salvia growing there.

This year our part of Texas has been very hot with very little rain so my garden was watered from local water supply which contains lots of chemicals. I am wondering if the stress of the heat and chemicals could have brought the problem on?

I will put down heavy plastic today so I can solarize the bed. In a month or so I plan to plant marigolds thickly in that bed and may use that bed for garlic or onions this Fall/Winter.

Any further suggestions welcomed.

Peggy