Jo,

Although nematodes are not as common in clay soil as in sandy soil, they can and do exist in clay soil---they're just much more common in soils with a high sand content.

With the tomato plants you just pulled, did you see the galls on the roots that indicate nematodes? I think you did see them on the earlier plants that showed RKN damage, right? (And, for anyone else who has not seen the damage root knot nematodes can do to the roots of plants, click on the link below and you'll see what Jo and I are talking about.)

You still can plant Elbon rye. It is probably the most cold-hardy cover crop we have, and it should be able to sprout and grow even from a mid-October planting in our climate, especially this year with the hot days hanging on and hanging on.

It is likely that if you have nematodes in any of the soil on your place, you have them everywhere, and they absolutely will move into your raised beds.

When we were looking for land here in the mid-1990s, we had a couple of things we were looking for: (1) acreage, (2) with trees, (3) with ponds or creeks and (4) with clay soil. You wouldn't think a gardener would deliberately choose clay soil, but I did and it was because I didn't want to spend the rest of my life fighting nematodes.

You could solarize too, but due to the time of the year, the less intense sun and heat, etc., it may not be as effective as solarizing is during the hot summer months.

If I were in your shoes, I'd focus on adding tons of organic matter, and I'd check into all the research on the effectiveness of chitosan on nematodes.

Finally, because you are serious about growing as much of your produce supply as possible there in your garden, you might want to contact your county agriculture extension agent for guidance on how best to approach the nematode problem. I wonder if there is any sort of test the OSU lab can do that could help you determine how heavy your nematode infestation might be?

Dawn

Here is a link that might be useful: Images of Nematode-damaged Roots

Jo, sorry to hear you have found more nematodes.

I planted rye last Wed. and will plant more over the next 3 or 4 weeks. I plant as space opens up. It seems as tho the later I plant the longer it takes it to come up, and 4 weeks from now may be pushing it too much. I will just watch the weather and make the call when the crops come out.

Larry

Dawn I did see galls. Should have taken a pic because there were almost no normal roots...just big balls.

Surprised they survived as long as they did.

I baby the crap out of my plants and have added: dilute skim milk (fungicide) cornmeal (fungicide), tomato tone, dry molasses (natural fertilizer). I spray with neem and fish oil once every 10 days or so, bt in the spring every other week. Occasional Epsom salts (once monthly). I mulch and water and treat them like my kids.

My next step is to Elbonize them (I made that word up) followed by winter solarization. I Started worm composting so I should have a bunch of castings soon.

It just feels so unfair.

Jo

Jo, Yes, it feels unfair and I suppose it is unfair, but life isn't fair. Please try not to take the nematodes personally....they're just little soil-borne critters doing their best to survive. One problem with nematodes is the way they can spread...for example, on soil clinging to your shoe or a shovel or whatever...or even in water if you have irrigation or rain run-off from a nematode-infested bed, that water can enable the nematodes to move around on your property, so to speak.

Anything you can do to improve soil health and plant health will help, but what will help more than anything is to plant vegetable varieties that have some nematode resistance bred into them. There's quite a few hybrid tomatoes with nematode resistance and most of them will give you a crop, whereas tomatoes without nematode resistance likely will not. With heirlooms, though, you just have to try the various ones and see if any given heirloom tomato variety has enough natural nematode resistance to produce a crop in nematode-infested soil.....but that gives me an idea and I need to ask Jay and Gary what they think. Watch for a thread on grafting tomatoes.

If I were dealing with nematodes, I think I'd continue to add all the organic matter I could on an ongoing basis, but probably would move my tomatoes to large containers (I use molasses feed tubs for some indeterminate tomatoes and they work just fine...I'd say they hold roughly 20 gallons worth of soil). I'd also do just what you're doing....solarizing when possible and growing Elbon rye every year in the cool season. You know, it also helps to let land lie fallow (but you have to keep the weeds out of the fallow soil or the nematodes can exist in them) every other year, but I'd find that hard to do. It would make me crazy to have to rotate back and forth between two separate garden plots every year.

Now, let me work on the grafting idea.

Dawn

I've been finding bits of info here and there that Neem oil can destroy nematodes. Hey, I already have Neem oil! I just can't find directions. I'm wondering if I should just mix some with a bucket of water and dump it in the soil.

Jo

Jo, I have never heard of neem oil killing nematodes. I would think anything that would kill nematodes might kill a lot of things that I might not want to kill.

The rye I planted on the 13th. is up today. I expect to be planting more in a few days when my green beans are tilled in.

Larry

Larry, I planted my Elbon mid Sept and I tilled it as soon as it hit 12" in the beds I planted it in. I read somewhere that over 12" and it's impossible to till. Just planted some more and added some dried molasses. I had a bag from a feed store, and I'm reading tons of studies right now that say molasses inhibits nematode egg hatching and juvenile development. I would prefer to use these beds again next year, so I am also researching chitin. Oh I read an Australian study that got great results from sawdust and urea...Can I just pee in my garden :D???

Jo

jo, i'm so sorry that this is going on... i'd be in tears. i have absolutely no good info to pass on, but i do want you to know that i feel for you....i've never even looked at a root when i've pulled a plant, but now i will. come over and have a cuppa sometime. :)

dody

Jo, over 12" is the pitts. Being that I see no signs of nematodes I just plan on letting mine go till near planting time and trying to kill it and mulch over it. This will be new to me and may not work. My new garden I will I will till in because I am in bad need of organic matter.

Yes, go ahead and pee in your garden, I do,but wait til the plants are about 3' tall so the cars on the street wont be honking.

Larry

Jo,

Like Larry, I've never seen any quantifiable independent research that shows neem oil applied to soil has any effect on nematodes, although I have seen such claims made by those who benefit from selling neem.

I would never apply neem to soil because it likely would kill some of the good microbes in the soil which then would leave your soil less healthy.

Remember that healthy soil is full of all kinds of biologically active creatures, which I tend to lump together in a group and call "microbes". What are these microbes and how many are there? The microorganisms include all sorts of microscopic plants and animals, including nematodes (there are beneficial ones, you know), fungi, actinomycetes, bacteria, yeast, germs, protozoa and algae. Healthy soil that has a good compost/humus content is believed to have as many as 50 billion microbes in 1 tablespoon of soil, according to organic gardening expert and author J. Howard Garrett, aka 'The Dirt Doctor'. Since all the microbes in soil play an important role in soil health, you don't want to put anything in the soil that would hurt those microbes.

I'll use spider mites as an example of the unintended consequences of using a 'cide' to kill the bad pests and inadvertently killing beneficial insects too. While spider mites are a pest in certain circumstances, there are beneficial predatory mites that help keep the spider mites under control.

When you spray a miticide on plants infested with spider mites, you kill not only some of the spider mites (most pesticides do not kill 100% of the pests) but also the predatory mites that help keep the number of spider mites down. When the mite population rebounds (and it always does), the pesky herbivore spider mites bounce back first because they feed on plants and plants are readily available so they have an endless food source. Then, in a much more slow manner, the predatory mite population, which are carnivores, rebounds.

The problem is that beneficial insects rebound very slowly because the 'mamas' don't reproduce until there's already a good food source for their babies to eat. So, while the mama predatory mites are waiting for the food source to increase to the level they need, the spider mite population is growing very rapidly and getting out of control. Once the predatory mite population begins to surge and feed upon the spider mites, the spider mites have a huge head start and your plants are severely damaged.

I think if you used neem in soil, you'd likely kill off a good portion of the microbes in the soil, leaving your soil less healthy, less fertile and more vulnerable to soil-borne pests, including root knot nematodes and various soil-borne diseases.

So, even if the idea of trying neem is attractive, it could hurt more than it might help.

I used the spider mite example to illustrate how using a 'cide' for pest control can backfire because it is the story of my life. My dad was a terrific gardener, but he fought spider mites my entire childhood, and he lost that battle in late July or so of every year, and so did his best gardening buddy, Mr. Camp. I watched the two of them try everything to kill those spider mites, but the spider mites always outlived and outlasted their efforts. So, I grew up thinking that no matter what you did, you would lose your tomato plants to spider mites in July.

Eventually I grew up and had a home of my own and my own garden. During our second year in our house, we decided we wouldn't 'poison' our tomato plants with the miticide commonly sold to home gardeners back then. A miticide didn't help the first year in our new home when we did use it, so it seemed pointless to spend money buying it and then spend time spraying it on the plants the second year. What happened? Our spider mites didn't get out of control and our tomato plants didn't die. Once I convinced my dad to give up miticides, he never lost his tomato plants to spider mites again. Still, it probably was another dozen years or so before I finally understood why not using a miticide saved our plants from the mites, and that's because I didn't know back then that there was such a thing as predatory mites.

So, I hope that tale illustrates the dangers of even attempting to use a soil treatment to kill the root knot nematodes. Even if it would kill the nematodes (which I highly doubt), it would kill all the other microbial life in the soil. As an organic gardener that is absolutely the last thing you need. Even worse, what I think most likely is the neem oil would kill the good microbes, but not the root knot nematodes.

When I am trying to figure out what to use in my garden or landscape, I fall back on that old adage used by physicians.... "first, do no harm".

You might have a chance of killing some of the root knot nematodes by applying beneficial nematodes to the soil. The most important factor affecting the efficacy of beneficial nematodes would be to apply them at precisely the exact temperature they need, and also to use the right beneficial nematodes.

Dawn

I was reading the Arbico organics catalog and I looked in the index under nematodes, root knot. The recommended remedy was Neem so I started Googling.

But Dawn, you're right, I don't want to kill my beneficials.

I think my plan of attack so far is this:

1. Elbon Rye cover crop yearly.
2. Lots of organic matter.
3. Solarize when possible.
4. Pee in the garden :D
5. Add dried molasses from time to time
6. Plant resistant varieties.
7. Potentially try grafting a few if I am feeling brave.
8. Grow a few spares in containers in case measures 1-7 don't work.

Jo

Jo,

Add these to your list....

9. Pray.
10. Buy a lucky rabbit's foot.
11. Hire a good witch to cast spells on the nematodes.
12. Dump sugar and/or dry molasses (available at some feed stores in 50-lb. bags) into your garden beds. Sugar or dry molasses stimulate microbial growth and the more good microbial activity your garden has, the fewer problems, including RKNs, you'll have.

I normally wouldn't argue with Arbico's advice, but I think it is not the best advice in this case. In some studies, nematodes did not seem to be particularly affected by any sort of neem oil product being added to the beds. In some studies, neem cake seemed effective up to a certain point. Still, I wonder, even if neem cake worked on the nematodes, how much would it harm the microbes. One thing about neem that is well-known is that it degrades quickly when exposed to sunlight and also degrades quickly in soil. So, even if you poured neem oil, or neem cake, into your beds it likely wouldn't have a great effect on nematodes as it would begin to break down and degrade before it worked its way down very deeply into the soil. The nematodes, unfortunately, can go deeply into the soil and that's one reason some people think solarizing is not very effective...because it only kills nematodes in the upper few inches of soil but does nothing to the ones further down in the soil. That's why solarization has to be part of an overall program that attacks the nematodes in every possible way....crop rotation, using reistant or tolerant varieties, solarization, growing Elbon rye, fallowing every other year if necessary, improving the soil with organic matter, etc.

Dawn

I've never had to deal with nematodes but was reading up on them a little last night and someone said to put a ratio of 1/2 cup of sugar to 1 gallon of water and to drench the bed with it.

I've also heard that neem oil can help the situation but that it's more of helping it out as time goes on rather than an immediate fix. Why it works though is a mystery to me.

LOL, Larry you made me laugh about the plant height thing :-) Definitely watch for the cars when you're ammending your soil in this way Jo!

Interesting and seemingly faultless logic, Dawn. And, apparently upheld by practice. From a biological/ecological approach, choices #6 and #7 seem the most promising--and # 7 is really #6 with some trickery.

Evolution has already done most of the work for you if you choose approach #7 and start with root stock that already has evolved a resistance to the nematodes (or whatever else you are trying to avoid). The pesky details are the grafting process, although it seems to me there should be some simple and inexpensive devices out there that are the equivalent of "pill splitters" that could perform the grafting cuts on seedlings simultaneously and all one would have to do is plug the two ends together with the banding.

By the way, I found the connection to the grafting machine you put on another thread most fascinating.

i have heard planting certain types of marigolds help control nematodes....
plant with tomatoes...turn marigold plants under after season

MJandkids, Sugar helps because it increases biological activity in the soil, but using beneficial nematodes tends to help a lot more.

Robert, Isn't the grafting machine fascinating? If I didn't already plant more than one sane person can maintain, I'd try grafting just for the fun of it.

Butchfomby, Marigolds are overrated. You have to plant them solid like grass and till them into the soil afterwards, and many people don't find that they make much difference in their nematode level. At our place, marigolds attract spider mites, so I plant them near (but not right beside) my tomato plants as a trap crop for spider mites. Once the marigolds are covered with spider mites, I pull them up, put them in a sealed garbage bag and dispose of the plants, spider mites and all. I grew the Nemagone marigolds one year and they were huge (5' to 6' tall), reseeded all over creation, and I cannot imagine planting them all around existing tomato plants because they would be competing with them for water and nutrients. I then had the very invasive nemagone mariolds popping up all over the yard and garden for years afterwards even though I pulled every volunteer seedling before it could grow and produce more seed.

Dawn