RKN Control Attn: Dr. Carolyn

[JackE]

Dr Carolyn -

I have a technical query re RKN that you are best qualified to answer. I have read a lot of your material on this subject.

I have one RKN infested acre of coarse sandy loam that I have been clean-fallowing since the spring of 2010 - by frequent tilling, not herbicide. Between monthly tillings, I've ridged it up with a 14" middle buster plow to disturb the soil as deeply as possible and expose it to the sun.

It will be two years next spring, with a lot of extremely dry, very hot weather. There has been no living roots for the RKN to eat. I plan to plant cool weather crops there this winter, which will should be harvested before the soil temp warms-up enough for RKN activity - if there are any left alive.

Do you think I will be safe to plant tomatoes there in 2012 after I clean-up the spinach and carrots? Or should I fallow it again one more summer to be on the safe side? Or, would you recommend getting a soil test from a private lab before planting tomatoes. Our local extension office does not handle soil samples in a timely manner and all the nems will have died from old age before arriving at TX A&M!

Any advice is appreciated. Thank You.

Jack

[coloken]

WHAT IS RKN? ................

[carolyn137]

Originally Posted by JackE

Dr Carolyn -

I have a technical query re RKN that you are best qualified to answer. I have read a lot of your material on this subject.

I have one RKN infested acre of coarse sandy loam that I have been clean-fallowing since the spring of 2010 - by frequent tilling, not herbicide. Between monthly tillings, I've ridged it up with a 14" middle buster plow to disturb the soil as deeply as possible and expose it to the sun.

It will be two years next spring, with a lot of extremely dry, very hot weather. There has been no living roots for the RKN to eat. I plan to plant cool weather crops there this winter, which will should be harvested before the soil temp warms-up enough for RKN activity - if there are any left alive.

Do you think I will be safe to plant tomatoes there in 2012 after I clean-up the spinach and carrots? Or should I fallow it again one more summer to be on the safe side? Or, would you recommend getting a soil test from a private lab before planting tomatoes. Our local extension office does not handle soil samples in a timely manner and all the nems will have died from old age before arriving at TX A&M!

Any advice is appreciated. Thank You.

Jack

Jack, I don't consider myself to be the best qualified to answer your questions b'c I have no personal experience at all with RKN's, growing where I do in the NE. What I have done over the years is to read about them in terms of being able to answer some of the questions that are asked.

And in Worth's Birthday thread where I answered you I said I hoped that others would also respond.

First, you already started a thread in the Market Garden Forum where I did participate and others who posted actually did have to contend with RKN's and I thought gave some good advice and here's that thread:

http://www.tomatoville.com/showthread.php?t=19465

This AM I did a general Google search entering.... sandy loam root knot nematodes Texas..... and while there were many valuable articles I thought the following was especially good:

http://agrilife.org/today/2010/12/22...knot-nematode/

I tried to link to that general Google search but when I do it deletes what I'd already written, but I gave you the words I used so you can do it yourself.

A few points.

I saw no one who was using deep tillage to try to lower the RKN burden.

RKN's don't need to have roots to feed off of, as you posted above.

RKN's can remain in sandy loam for years b'c their eggs can remain dormant.

I can't see how sending soil samples to TAMU would help b'c they're not going to do egg counts, let alone attempt to assay for live or dead RKN's and the RKN's don't need to be alive to do a count anyway.

If I were you, since you're commercial, I'd contact your local Coop-extension, that's what they're there for, and/or they might refer you to a specialist at Texas A and M.

But I'm not in a position to suggest to you that your fields would be OK for tomatoes next year. That advice must come from someone who knows more than I do, by far, about commercial growing fields and RKN's.

I feel comfortable, to a certain degree, making some suggestions to hobby gardeners but certainly not to commercial market gardeners.

And again, take a look at the first link I put up about your earlier thread about RKN's where some good suggestions, I thought, were already suggested, but again, those were mostly hobby tomato growers unlike you who are a commercial market gardener.

And there is a big difference in many ways starting with what products you might want to try and if so do you need a pesticide license. You don't need one for the Actinovate that was so highly suggested in the second link but it is expensive, that I know.

Best I can do and since about 1982 I've signed off as Carolyn at every message site where I've participated. There's my academic career where I was called Dr. Carolyn and I'velong been retired, and then my private life where I'm called Carolyn, so please call me Carolyn.

[carolyn137]

Originally Posted by coloken

WHAT IS RKN? ................

RKN is short for Root Knot Nematodes which you don't have in Colorado which I know b'c I lived in C0 for many years. RKN's can't exist in soils where the ground freezes deeply and for sure the ground freezes deeply in CO as I know from living there.

There are different species of RKN's and that was discussed in the first link I gave to Jack which was a thread already here at Tville.

If you see RKN's at any comprehensive disease sites you'll usually see RKN's as well b'c they throw up any and all tomato diseases and usually don't indicate where those diseases are found and/or are most prevalent.

[JackE]

[/QUOTE]RKN's can remain in sandy loam for years b'c their eggs can remain dormant.
[QUOTE]

That's pretty close to the last thing I wanted to hear, Carolyn But thank you so much for responding.

We're actually "semi-commercial" - an all volunteer, non-profit - faith-based charity. We give away our produce to needy families, but we do accept donations to help with expenses when offered voluntarily.

[carolyn137]

RKN's can remain in sandy loam for years b'c their eggs can remain dormant.

That's pretty close to the last thing I wanted to hear, Carolyn But thank you so much for responding.

We're actually "semi-commercial" - an all volunteer, non-profit - faith-based charity. We give away our produce to needy families, but we do accept donations to help with expenses when offered voluntarily.

Jack, I was only the messenger for that bit about the eggs remaining dormant for so long in sandy loam was from the second link I gave.

[JackE]

Carolyn, we have a tech advisor for our project, one of our church members with a degree in agronomy and a license, who must approve any and all chemicals we use. He will not approve any of the conventional RKN chems currently on the market. He is not "organic", but he says they are just too toxic for us to use - and we don't have access to the right equipment. We would have to hire a commercial applicator.

He added that the biological controls presently available are largely ineffective without heavy organic content in the soil, which we lack. There are, however. some promising organic solutions on the works that will hopefully take the place of the now banned methyl chloride, such as Melo-Con from CertusUSA, which uses a live fungus. There is also a lot of research in the area of GMO's - which our tech advisor has no problem with.

The clean fallow and deep tillage was his idea. He is not a row crop man - he manages a 5000 acre cattle ranch and grows hay. He studied all that stuff in college, but I don't think he knows that the eggs can survive in a dormant state. I didn't know that. I guess we just missed that in our studies. I just wish we had listened to you earlier.

Our extension agent is a forestry major and knows little about veg production. There is no commercial veg production in this county - probably due , in large measure, to the sterile, acidic sandy soil and severe RKN populations. They say here, in the Heart of the Texas Bible Belt, that "God created this soil only for pine trees."

My purpose here is just to get some "second opinions", as they say. Thank you for your input.

Jack

[carolyn137]

Jack, as I said, I was just the messenger about the dormant eggs and the other information.

You could have done the same as I did by just entering.....sandy loam texas root knot nematodes.... at Google.

And yes, you've mentioned the Cetus product in several of your threads and posts.

I'm fully aware of the problems that RKN's have and are causing with many of my tomato friends in areas where they exist, and I still will point you to the thread I linked here from a previous discussion of the issue where some of those folks I thought gave you some excellent suggestions for possible control.

If I were in your shoes I don't think I'd rely on current info from a church member who perhaps has outdated info and I find it hard to believe that an Extension agent tied to Texas A and M can only advise on forest related issues. That person's job is to refer folks back to specialists if he or she is unable to help someone with a problem and you also have the possibility of contacting Texas A and M directly via their website as I recall or one of the Master Gardener websites tied to TAMU.

[JackE]

Carolyn:

I do have some direct access to A&M Professors, but use them only when absolutely necessary - as a last resort (like identifying weeds for selective herbicides). Our extension agent knows nothing about veggies or their pests and diseases - and I'm not real sure she knows a whole lot about pine trees, for that matter! The timber companies have a whole staff of pHD's at their disposal - and they sure don't need any advice from her! The office is a total waste of state funds - absolutely useless to anyone. They have a full-time "home economist" to work with our poor folks - she's white, middle class, and not well-accepted in the minority communities where the poor people live! It's just a cushy state job with no actual work. I know - because poor folks tell me about these matters at our veg stand.

It's been many, many years since we had a useful ext agent - not since the forties and fifties when rural people were completely ignorant (my mother sprayed my brother and I, naked, with DDT to kill the ticks and lice!). Our state ag ext service is now a costly, worthless anachronism and it should either be abolished or the legislature should fund it adequately to hire well-qualified people (and that ain't gonna happen in this strongly conservative state).

Jack

[wmontanez]

I am way out of my league in this topic and I am just a hobbie organic gardener... I have read that marigold roots (tagetes) supresses root-knot nematodes by intercroping with tomatoes (Roma VFN has tolerance to nematodes) if you dare to try a test plot.

I found a paper that has a study that claims the following "Neem cake was found to be most efficacious against root-knot nematode and was at par with chemical nematicides"

Read here: http://eprints.hec.gov.pk/1355/1/1059.html.htm

[carolyn137]

Originally Posted by wmontanez

I am way out of my league in this topic and I am just a hobbie organic gardener... I have read that marigold roots (tagetes) supresses root-knot nematodes by intercroping with tomatoes (Roma VFN has tolerance to nematodes) if you dare to try a test plot.

I found a paper that has a study that claims the following "Neem cake was found to be most efficacious against root-knot nematode and was at par with chemical nematicides"

Read here: http://eprints.hec.gov.pk/1355/1/1059.html.htm

There are many websites here in the US that also discuss the use of Tagetes type marigolds but the fact is you have to plant the whole garden area for a complete season with them, not just plant ehr tomato plants.

They act as a trap crop b'c the RKN's infect them but can't muliply within them. Then you till them under at the end of the season.

http://www.google.com/#hl=en&sugexp=...f98bc7f00dda4f

Above is info about the Neem Cakes youjmentioned above. Can read and see what you think about them as being nematocidal, at least the ones that aren't straight manure and have another agent added.

I think the best discussion of using mariglds is at the NCSU organic control website.

Park Seeds also introduced a variety call Nemagon, I think was the name, also a Marigold but I haven't seen too many positive comments about that one either.

There are many many varieties, most of the F1 hybirds, that have tolerance, not resistance to RKN's as indicated by the N next to the variety name, but tolerance only gives the plants a week or two more ot produve but that's of major interst to comercial lartge scale famers who do Brix measurements on the fruits ( soluble sugars) to tell them when to harvest and that week or two can make a big difference in getting the Brix level up.

[JackE]

I was a home gardener until I retired. I planted marigolds until I was blue in the face. I think I've tried it all except neem cake/oil - but elbon rye, molasses, sweet corn as a trap (the old timers pulled the infected roots up immediately after harvest -my job as a child), all sorts of brassicas - in short, I think I tried just about everything anyone suggested in the literature of the time, including solarization under plastic. I was an inveterate organic gardener in those days - a fanatic follower of J.I. Rodale and Organic Gardening Magazine and it's staff of writers. I have long since moderated my views - after offending all my friends and neighbors. LOL.

What defeated my organic career was the utter impossibility of building this sand soil into a rich growing medium with compost. Nobody could have worked harder on that than I did!! For years and years of heartbreaking effort!! It was not possible to achieve, even in a small garden plot. What works here is maintaining a sterile growing medium and providing all nutrients chemically. Please believe me - I didn't come to that unfortunate conclusion lightly - just ask my wife and neighbors.

After years of struggle, I finally realized that the only way to whip RKN is to plant your garden somewhere else. Fortunately, I had the land to do this. When RKN damage began to approach unacceptable levels, I simply broke-up another 2000 sq ft of pasture and I was good for several more years. I noticed that the pasture grass didn't do as well in the infested areas for years thereafter. It seems that nematodes stunt and inhibit pasture grasses such as bermuda or bahia for some time, but never seem to bother well established grasses and weeds. They eventually die-out in a grass/weed environment. I have recently replanted an area that was a severely infested and abandoned ten years ago, and it seems nematode free (for the time being!)LOL.

Another option, which my grandfather used, was to plant everything very early and get it in before soil temps warmed-up. Nems are dormant up to about 70 degrees and don't really create much of a problem until soil temp passes 80. My grandfather planted before the last frost date and replanted if necessary - some years he got tomatoes and some years he didn't. Some crops, like cowpeas, sweet potatoes and corn, have a LITTLE natural resistance (meaning you might salvage some of the crop), but others, like okra, are quickly and totally killed.

Carolyn, if they aren't feeding on the roots, what DO they eat? It always seemed to help some when we pulled-up the gall-covered roots and burned them.

After many years of fighting this battle, my bottom line advice is to either use conventional chemicals like the big Florida growers (all REALLY bad!!) along with resistant hybrids (NOT a panacea either!) or clean fallow the soil for at least a couple years - longer, I guess, if the eggs are dormant for years. Deep tilling does help as well - in our hot summer sun even a dormant nematode egg is going to be very uncomfortable LOL.

Jack

[carolyn137]

Jack, as to how RKN's persist when the eggs aren't dormant, and multiply to large populations, as in what keeps them alive, I'm linking to a Google search on the Life Cycle of Nematodes.

Note that there are many kinds of Nematodes so you want to look at life cycles that include the ones known to infect tomatoes.

http://www.google.com/#hl=en&sugexp=...iw=757&bih=403

I'm not a nematologist, I've never had any personal experience with RKN's and in the link I gave to your previous thread in my first post to you in this thread there were those who did give you some excellent advice who DID have such experience.

You said above you now have an RKN field that seems OK but in the future you might want to consider even raised beds. As I recall it's Suze who raises so many beautiful tomato plants in her raised beds who was also the one who went into great detail about what she uses to thwart RKN's

So at this point I'm bowing out and letting you read the link I just posted and perhaps suggesting that if you have additional questions that you again consider talking with the specialists at Texas A and M b'c I think at this point you've mined the minds of those here who have posted about RKN's.

So good luck and good growing.

[JackE]

Okay - I have no more business here. Not everyone just likes to "visit" as I do. :-)

Jack

[ssi912]

a couple of seasons ago i had a real bad nematode infestation. i dont know what variety it was, but i believe rkn. i pulled all all of the plants, forked soil, added a couple bags of pulverized pine bark, watered it in real well and covered the bed with a sheet of clear plastic. let it it sit from mid july to late august. removed plastic, did not till, and covered bare soil with about 3 inches of hay. the nematode problem occured in 2010 season. after pulling my plants in 2011, no signs of nematode damage. one of the best crops i ever had. we are trying this proceess at our community garden in a few of the plots. nematodes population there is extrememly high there because of lack of rotation. we only covered 10 rows, three feet wide. left plastic on for the same amount of time. we shall see how well it worked next june. i grew a marigold variety called nemagone in my raised bed this year. filled the whole bed with the marigold. i plan on chopping and mixing it in a few weeks from now. will not know until nex summer though. good luck with your efforts. if you find anything that works, let us know.