Root Problem (Root Knot Nematodes?)

mwancho · July 18, 2011

Hello,

I planted my first garden in our (new to us) house this past April. I have been very pleased with the results and excited by everything there is to learn. My favorite and first to produce fruit was a Taxi. The first tomato I pulled off was a pretty good size, the ones that followed weren't nearly as large. The Taxi has since died off (I took some experimental sucker cuttings which are rooting in water at the moment) and I pulled it. Upon inspection, I found knotty roots. I'm wondering if this could be a result of root knot nematodes. Another interesting tidbit: I found an old journal entry from the previous owners at one point which stated something about turning the tomato beds and there being no nematodes that year. If this is in fact root knot nematodes, I'll plan to innoculate this bed next summer using the solar method.

Your expert advice is greatly appreciated.

--
Mark

b54red · July 19, 2011

I used to have major problems with nematodes. It seems that adding both horse and cow manure decrease the incidence of nematodes over time. I have also had good luck with a type of marigold planted among my tomatoes called Nemagone. Sugar added to the soil prior to planting time also seems to help. I have had no nematodes this year on a single plant that I have pulled up yet just 10 years ago nearly every plant would have some degree of nematode damage to the roots. I think all of the things mentioned above helped reduce the nematode problem. Maybe they each had some impact. I just know that one or all of them has resulted in a garden that seems to be nearly entirely free of nematodes.

**carolyn137** · July 19, 2011

RKN's can be a real problem for lots of folks and I know some in CA who have had to go to container growing, but there are some things you can do that have been shown to help.

RKN's usually build up to large populations where the soil is mostly sandy and the ground doesn't freeze deeply in the winter, so they're primarily found on the East Coast from about VA down to FL and then along the Gulf Coast up into CA. But there are pockets of them sometimes in other states, and in some cases it's known that they were introduced on already infected plants.

Solarization is not the best way to go and besides you have to take the whole garden area out of use for a long time. Growing Ebon rye has been tried by many and then turning it under. SOme have tried crab and shrimp shells with not much luck and some have tried molasses and a while host of other things.

Yes, it was originally found that Tagetes type marigolds had some nemocidal properties and were also a trap crop b'c when infected the marigolds died and the RKN's with them.

But with time it's also been shown that planting those type marigolds casually amongst the tomato plants doesn't do it. You have to plant the whole are in question with them, very thickly and then turn them under and that also takes the garden area out for use for the whole season.

I think understanding how RKN's build up to high populations helps folks to understand WHY it's so important to continually add organic material to the suspect area, year after year after year.

RKN's move from sand grain to sand grain via the watershell around each grain and in that way spread and multiply.

So you have to get the sand grains farther apart so they can't do that and that means adding organic material to separate those grains farther apart.

Tomato varieties that are RKN tolerant, mainly the hybrids that have that gene bred in, only give the plants a bit more time before they go down, which is true of most of the tolerant genes for other systemic diseases such as Fusarium and Verticillium, etc.

So think adding organic material as the best way to make the situation better.

mwancho · July 19, 2011

Carolyn, B54,

Thanks for your replies. I'm relieved to know that the problem has been positively identified as RKN so now I can move forward with the techniques you have prescribed. I do have rather sandy soil in my raised beds which probably doesn't get adequate frost (even though we had some of the coldest temperatures on record this past February.) I added compost, but not nearly enough when I turned the beds before planting. I have another couple of bags, so I'll turn them in and plant some cereal rye for the winter, then shred and turn the rye in to the beds in late February/early March along with some alfalfa pellets and Epsom salts as I believe I may have also had some magnesium or other mineral deficiencies. It sounds like the remediation of these pests will be a several-season task, but I should look forward to healthier plants and a better yield next year. What an exciting adventure this has become!

--
Mark

b54red · July 19, 2011

I have found that adding cow or horse manure is really important in keeping nematodes under control. Next year I will not be able to add any to my beds because they are so full. I may see some return next year but maybe it will take as long for them to return as it did to get rid of them.

**mdvpc** · July 20, 2011

Mark

Here is a link to look at. Its a Tucson company I have bought from before:

http://www.arbico-organics.com/produ...itic-nematodes

Worth1 · July 20, 2011

More information.
http://www.google.com/url?sa=t&sourc...nRJ8CQ&cad=rja

Worth

July 19, 2011	#3
carolyn137 Moderator Emeritus Join Date: Jan 2006 Location: Upstate NY, zone 4b/5a Posts: 21,169	RKN's can be a real problem for lots of folks and I know some in CA who have had to go to container growing, but there are some things you can do that have been shown to help. RKN's usually build up to large populations where the soil is mostly sandy and the ground doesn't freeze deeply in the winter, so they're primarily found on the East Coast from about VA down to FL and then along the Gulf Coast up into CA. But there are pockets of them sometimes in other states, and in some cases it's known that they were introduced on already infected plants. Solarization is not the best way to go and besides you have to take the whole garden area out of use for a long time. Growing Ebon rye has been tried by many and then turning it under. SOme have tried crab and shrimp shells with not much luck and some have tried molasses and a while host of other things. Yes, it was originally found that Tagetes type marigolds had some nemocidal properties and were also a trap crop b'c when infected the marigolds died and the RKN's with them. But with time it's also been shown that planting those type marigolds casually amongst the tomato plants doesn't do it. You have to plant the whole are in question with them, very thickly and then turn them under and that also takes the garden area out for use for the whole season. I think understanding how RKN's build up to high populations helps folks to understand WHY it's so important to continually add organic material to the suspect area, year after year after year. RKN's move from sand grain to sand grain via the watershell around each grain and in that way spread and multiply. So you have to get the sand grains farther apart so they can't do that and that means adding organic material to separate those grains farther apart. Tomato varieties that are RKN tolerant, mainly the hybrids that have that gene bred in, only give the plants a bit more time before they go down, which is true of most of the tolerant genes for other systemic diseases such as Fusarium and Verticillium, etc. So think adding organic material as the best way to make the situation better. __________________ Carolyn

July 19, 2011	#4
mwancho Tomatovillian™ Join Date: May 2011 Location: SW TX Posts: 16	Carolyn, B54, Thanks for your replies. I'm relieved to know that the problem has been positively identified as RKN so now I can move forward with the techniques you have prescribed. I do have rather sandy soil in my raised beds which probably doesn't get adequate frost (even though we had some of the coldest temperatures on record this past February.) I added compost, but not nearly enough when I turned the beds before planting. I have another couple of bags, so I'll turn them in and plant some cereal rye for the winter, then shred and turn the rye in to the beds in late February/early March along with some alfalfa pellets and Epsom salts as I believe I may have also had some magnesium or other mineral deficiencies. It sounds like the remediation of these pests will be a several-season task, but I should look forward to healthier plants and a better yield next year. What an exciting adventure this has become! -- Mark Last edited by mwancho; July 20, 2011 at 01:07 AM.

July 20, 2011	#6
mdvpc Tomatoville® Moderator Join Date: Jan 2006 Location: San Antonio, Texas Posts: 4,386	Mark Here is a link to look at. Its a Tucson company I have bought from before: http://www.arbico-organics.com/produ...itic-nematodes __________________ Michael

July 19, 2011	#2
b54red Tomatovillian™ Join Date: Sep 2009 Location: Alabama Posts: 7,068	I used to have major problems with nematodes. It seems that adding both horse and cow manure decrease the incidence of nematodes over time. I have also had good luck with a type of marigold planted among my tomatoes called Nemagone. Sugar added to the soil prior to planting time also seems to help. I have had no nematodes this year on a single plant that I have pulled up yet just 10 years ago nearly every plant would have some degree of nematode damage to the roots. I think all of the things mentioned above helped reduce the nematode problem. Maybe they each had some impact. I just know that one or all of them has resulted in a garden that seems to be nearly entirely free of nematodes.

July 20, 2011	#7
Worth1 Tomatovillian™ Join Date: Feb 2006 Location: Den of Drunken Fools Posts: 38,539	More information. http://www.google.com/url?sa=t&sourc...nRJ8CQ&cad=rja Worth