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Root Knot Nematodes RKN Control (organic)

Posted by loslunasfarms 7, New Mexico (My Page) on
Sat, Feb 14, 09 at 2:49

Well, since I have already discussed the "NAPALM" chemical aka temik for control of nematodes, I figured that I would now thing of more natural way of controlling RKN in pot culture.

I just started playing with Neem oil for control of fungus gnats. MAN, I hate those things. I have probabbly lost about 100 cuttings so far to those &**&^^ things. Well, after reading Dr Taplas musings/comments on Neem, I wondered if it can be used for RKN.

It seems neem oil does have an effect on RKN. I know some of have trees in pots that we are going to pitch due to RKN; I know 4 trees I just found that have RKN, which were purchased at a local nursery. Well, I my just have to try a drench, root dip, and any other ideas? (The heat treatment works great.) Can you imagine saving a tree from RKN? Any who, just thought I would let some of the great minds on the forum, mull this over.

Here is what I have found:

Effects on Other Organisms

Although neem's effects on pestiferous insects are by far the best known, the tree's various products can influence other pest organisms as well. In the long run, these may well prove the most important of all. At present, however, the effects on noninsect pests are poorly understood. This chapter highlights some of the findings to date.

Neem products affect various types of nematodes. This may be significant because certain of these thread worms are among the most devastating agricultural pests and are also among the most difficult to control. In addition, an increasing number of synthetic nematocides have had to be withdrawn from the market for toxicological reasons.

Today, there is a small but increasing body of evidence that neem might provide useful replacements. Certain limonoid fractions extracted from neem kernels are proving active against root-knot nematodes, the type most devastating to plants. They inhibit the larvae from emerging and the eggs from hatching, and in at least one test they have done so at concentrations in the parts-per-million range.1 Water extracts of neem cake (the residue remaining after the oil has been pressed out of the seeds) are also nematocidal.

In a careful trial in Aligarh, India, amending soil with sawdust and neem cake dropped the root-knot index to zero and, of all the treatments tested, gave the greatest growth of tomatoes, a crop that is very sensitive to these nematodes.

In tests in a greenhouse and in the field in Germany, tomato plants were obviously improved by neem products, but there was no significant difference in the numbers of some nematode species in the soil. However, among treated and untreated soils the majority was extracted from the roots of plants in untreated soil.2

Here is the other link:

Here is the google search:

And another link to a google book:

Whew, I am tired. Good night!

Follow-Up Postings:

RE: Root Knot Nematodes RKN Control (organic)

Good Stuff! I really appreciate the research!


RE: Root Knot Nematodes RKN Control (organic)

Has anyone tried neem cakes on their fig soil?? (You know a little RKN fig trial.) This is very interesting idea to treat RKN. Not to say the least an organic treatment for RKN. Wow!!

RE: Root Knot Nematodes RKN Control (organic)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, May 10, 10 at 17:58

I was perusing the organic forum at Da>e's, when I stumbled on a reference to neem cake being used as a fix for RKN. Since I've always had a good deal of respect for the insecticidal effectiveness of the cold-pressed oil of the neem tree, the first thing I thought was this is something I should look into to see if it would work for those of you who have difficulty with the antagonists. One of the first things I noticed in my search was this post. I don't know how I missed it when it was originally posted back in 09. I would have thought that someone would pick up on this and run with it, as it sounds very promising. How about you, James? I know they give you fits.

Anyway - the thread deserves to be bumped. Whether or not it prompts anyone to take another look at it is something entirely different, but I know that if I was in RKN territory and having problems I'd sure be checking it out.


RE: Root Knot Nematodes RKN Control (organic)

Al, I was going to run experiment, but not sure entirely how to start it. I have 3pots with nematodes. What is funny is that these trees were given to me. I caught them as I was getting ready to put them in my orchard.

The problem is testing for 100% removal in pot. I dont want ground contamination.

RE: Root Knot Nematodes RKN Control (organic)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, May 11, 10 at 11:26

Do you have access to the neem cake? I haven't looked any further into it, but it would seem that incorporating it into your soil at repot time and maintaining the 3 trees for a year in isolation should tell the story about its effectiveness for trees under container culture. Since it's reputed to work at such low ppm concentrations (just like the oil) it would be interesting to have a couple of others try it in in situ applications to test effectiveness on trees planted out.

FWIW - I'm pretty sure you know you need to be very careful about any effluent that exits those containers because it will be contaminated with the RKNs, but others might not know that the tree doesn't have to be planted for them to spread.


RE: Root Knot Nematodes RKN Control (organic)

That is what got me mad. They didnt show the contamination until a year after up potting. I noticed the gals and then remembered that I have been waterting it for the last year in the same spot.


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