Nodules or Nematodes?

These are Kentucky Wonder bean roots. Are the little blobs nitrogen-fixing nodules or root nematodes? If they are nematodes, should I take them out of the compost pile?

Kinda hard to tell Kell with the pic. Have you got a magnifying glass and a pair of tweezers. Look under the mag glass and run the tweezers around on the surface of the nodes. Usually you can see the body of the nemedoes that way and anythign whte ya see take the tweezers and see if ya cna pull it out.

There good nemadoes and bad ones. Unles s ya had them identified, if it is nematodes I would take the plants off the pile.

I'm not sure if your picture shows just the normal nodules or root knot nematodes (RKN) - can't quite make up my mind. :-) It is sometimes hard to tell with beans.

What I'm seeing in addition to "nodules" is also some general swelling and increased root size, so based on that, I'm leaning towards thinking it's RKN. Could be wrong though. Have you had problems with RKN in the past, with beans or any other plants?

One way to test your soil is to gather some dirt from the area, put it in a quart pot, and sow a few cuke or squash seeds in it. Or just sow some in that general area. Then after 2-4 weeks, look at the roots. Cucurbits tend to be very sensitive to RKN, and will usually show the signs rather quickly. Of course, you can also send some soil to a lab to have it tested for RKN, but that's a quick at-home way to check.

In any case, if you have any doubts, I agree w/starlight, get 'em out of the compost pile.

I do have root nematodes and am severely limited in what tomato varieties I can grow because of it.

As for looking at the nodules under a magnifying glass, the roots quickly wilted and shriveled and there wasn't anything to see. I have more bean plants in the ground and when I pull them out, I'll check the roots. These nodules do look more like the lumps that nonresistant tomato plants get than like the nitrogen-fixing nodules that I find on vetch.

I see. Well, I have problems with RKN too, and that's what I'm kind of leaning towards in terms of what I see in your picture. Gotta say, it looks more like the dreaded galling to me, perhaps with some of the "good" nodules too.

I don't want to take your post too far off topic, but I did want to offer some thoughts in terms of your limits on tomato growing. I continue to grow whatever varieties I want here, with good results. But I do treat my soil with mustard powder, and also occasionally with a mustard and hot pepper based product - Dazitol - and they have helped significantly. I also don't plant more than one crop per year in the same area - eg, I don't plant my fall crop in areas/beds where I had a spring crop of any 'tode susceptible veggies.

Edit/more - These treatments also seem to be "good enough" for beans as well, in terms of getting a good to great crop from them before/if they succumb. But with cukes, I do now tend to just do them in containers only because they are so sensitive to RKN.

This message was edited Oct 29, 2008 10:59 PM

Please tell me more about the mustard powder.

I have been planting my winter and summer crops in the same area, but I could plant the winter stuff among the rose bushes and such since my winter plants are relatively small (mainly onions, garlic, lettuce, and radishes). My vegetable garden is small - maybe 200 ft2.

Tomatoes seem to be the only things that have really been hindered by nematodes, though in some cases I don't know what the normal production is. The zucchini produced like there was no tomorrow, as zucchini do. I usually get one or two winter squash or pumpkins per vine. I was satisfied with the bean production. The bell peppers were kind of small. The chile peppers were very productive. I am satisfied with the production of the nematode-resistant tomatoes, though the fruits are not as big as they are "supposed" to be.

My understanding is that bell peppers tend to be more susceptible to RKN than non-bell sweets (like Italian frying types, etc.) or hots, but I rarely grow bells anyway as the others produce better in my climate. In any case, I don't see any root galling or effects when I pull plants of hots, non-bells, and seasoning types. So, you might want to see if these work better for you than bells.

The mustard - You just want the plain powder, not brown or hot/oriental. I order my mustard powder from Penzey's, the one pound bags of Regular Mustard Powder. Product # 45210. Or you can pick it up elsewhere if you know of a place close by that has good prices and larger quantities. Two one pound bags will do 20-25 plants at planting time. But you'll want to have more on hand for later treatments, which are done once a month.

Instructions: At planting time place 4 tablespoons (1/4 cup) of powdered mustard in the plant hole around the roots. Water and then fill in the planting hole with soil. Top dress with 1/4 cup mustard, scratching in more around each plant once a month. These instructions are for tomatoes, but could of course be adapted to other plants.

The lady I originally got this tip from (posts as nandina on gardenweb) has suggested that sugar can help too, but I have not tried it. Her instructions: "Toss granulated sugar heavily over that section and water in. As you dig in each plant put a generous handful of sugar in the planting hole around the roots. Finish planting and water in each plant. Once a month top dress and scratch in several handfuls of sugar around each plant."

Hope this gives you some ideas. If you try either the mustard or sugar, or both - please let me know how it turns out.

If you do some google searches on the use of mustard and sugar for RKN, you'll find some interesting information. Especially on the mustard.

This message was edited Oct 30, 2008 3:41 PM

Thank you for the information. I will try mustard or both. (I am familiar with Penzey's.)

This is why I use earthboxes (EBs) to those not familiar with the term. You can't plant anything in the ground here, unless they are trees. I've tried and lost a lot of plants and of course $$$. Don't have any more problems now and grow the best quality ever.

I pulled out the rest of the beans and they didn't have any nodules. This is rather curious since they were planted 10 feet from the first group. The nodule-free group were planted where I had grown nematode-resistant tomatoes the year before. Maybe that had something to do with it?

I pulled out the pepper plants and they were o.k. I pulled out a volunteer squash plant and it had nodules. The zucchini are still producing so I left them.

"The nodule-free group were planted where I had grown nematode-resistant tomatoes the year before. Maybe that had something to do with it?"

Maybe so. In general, it seems that once you plant a host plant in a particular area, you've awakened the 'todes and provided something for them to feed on and multiply the population. Even though the roots of 'tode resistant/tolerant varieties are still "hosts", so to speak, as I am sure you've seen when you've pulled the plants and looked at the roots (some, but not as much damage), there will perhaps be less of an attraction for them in that area.

Major edit - because I read your original question/comment wrong. ;-)

This message was edited Nov 9, 2008 7:25 PM

Now that I think about it, that "nematode-free" area got rather infested with Vinca major over the winter. Any chance that vinca repels nematodes?

My neighbor is a fantastic organic gardener. She uses beneficial nematodes (they come on a little sponge that you soak in water) to fight the RKN. Neem cake is great for fighting RKN also. Neem cake is the residue left after pressing the oil from neem seeds and is sold in some organic supply stores.