Backyard Aquaponics
A place to discuss aquaponics

I just realized that I put some tomato transplants into my system that were nfected with root knot nematodes. I pulled one out that was failing and saw the nodules. Does anyone know if this parasite will survive in a flood and drain system? I have some other healthy plants that are probably susceptible and am worried that they will get infected too.

Hello!
I am not sure if it can survive in flood and drain or not.

I just looked at Actinovate's packaging, which is a biological pesticide, and uses a bacteria to fight molds and other stuff. I remembered that it had some mention of roots. My understanding is that this is safe for aquatic organisms like fish.

I thought it might work for the nematodes. It does work for some root issues, but it doesn't list nematodes. I think there may be another product like it that might work.

I would err on the side of caution, and try to keep them out of the system in the first place, until you get a more definitive answer. Sorry I couldn't help!

I have a long story and history dealing with RKNs. To make a long story short, drown them. After much research, very disappointing and frustrating results, and spending more money than I'm willing to admit, I came across an entomologist and had a conversation about my RKN "adventure". His answer ..... "drown em. They don't have gills and cannot survive being submerged for long periods." He said he used to manage over 300 acres of tomatoes and leaving their fields flooded for a while after the last harvest was their solution to RKNs.
Strip your bed(s) and dig around and find as much of the infected root pieces as you can. Cap the drain line of the bed(s) you want to treat and fill them to the top and let them sit for as long as you feel comfortable. I let mine sit for a week. I used city water with chlorine and such. Don't know if it made any difference, but made me feel better. I can't say that I am completely clean of the little RKN bastards, but my plants were doing much better than they have been for over 2 years.......till the hot weather kicked in. You probably won't get your system completely clear the first time. The microscopic worms will be in every nook and cranny. A couple will probably survive as well as the eggs that will hatch. I intend to isolate and flood my beds in between growing seasons till I'm reasonably certain my beds are clean of RKNs.
Hope this helps.
If you have multiple beds, you must do all the beds at the same time. Do not drain the water back into the system. Run airstones for the fish and cut back a little on the feed unless you have a separate filtration system going.

Hi Mgessert.
I have similar issues with tomatoes. For some reason tomatoes are very susceptible to nematodes.

My system is constant flood. I haven't worried about the nematodes as tomatoes grow so quickly and are easy to propagate The nematodes only seem to effect older tomatoes plant so I have been taking cutting & replacing the older plants when they start to loose vigour. I also grow tomatoes in my NFT system with no nematode problems.

I read that Mustard greens are a natural inoculant for nematodes, might be worth a try.

If you do enough research about RKNs you will read that a hot Chinese mustard plant, arugula, sunn hemp, and a specific variety of French marigolds may work as deterents. Tried em........didn't work. Found one chemical that works and is fish safe but it ain't cheap. Majestije will kill them on contact but expect to spend over $225 for 2.5 gallons.

If you do enough research about RKNs you will read that a hot Chinese mustard plant, arugula, sunn hemp, and a specific variety of French marigolds may work as deterents. Tried em........didn't work. Found one chemical that works and is fish safe but it ain't cheap. Majestije will kill them on contact but expect to spend over $225 for 2.5 gallons.

If you do enough research about RKNs you will read that a hot Chinese mustard plant, arugula, sunn hemp, and a specific variety of French marigolds may work as deterents. Tried em........didn't work. Found one chemical that works and is fish safe but it ain't cheap. Majestije will kill them on contact but expect to spend over $225 for 2.5 gallons.

Well durn. Multiple posts. Mod, please clean this up.

Wow, great information. You guys are such a big help. Thank you!

An update on the RKN issue. Leaving the growbeds capped and full of standing water does work. BUT, how long to keep the beds flooded is the question. After having my beds stripped of any vegetation and flooded for over a week I considered (hoped) my beds were cleaned , so I replanted. For the better part of this spring and summer my plants were doing quite nice. I noticed the okra was looking a bit off, so I inspected a couple of the plant's roots. The bastards are back. Looking into the life cycle of RKNs I read that the life of an RKN can be 25 days. One site said as much as 57 days. So, guess the beds needed to stay flooded much longer than I had allowed. I will be stripping my beds once again. I have been fighting RKNs for over 3 years and my patience is just about gone. The June and July heat here wasn't very nice to anything I had growing, so leaving my beds empty and flooded won't be such a great loss. But...... I am still pissed. So, if you're dealing with RKNs, find a way to isolate the infested bed(s) and flood them. I am going to add a gallon of bleach to each of my flooded beds and leave them for over 2 weeks.....maybe into early september. Probably doesn't need to be said, but......do not drain the beds into the fish tank.

How do RKNs react to temperature? Could you flood the bed, then isolate it and stick in a bucket or aquarium heater to keep the temp up at 80 or 90? Using bleach will kill everything, good and bad. High temp's might too, IDK. But at least you won't have bleach saturated media - if you are using volcanic rock or clay pebbles. Gravel may not absorb the bleach.

I have had more "trial and error, maybe, could work, how about, try this" events in the past years to almost write a small book. The ultra simple solution of drowniong them works if given enough time, which I evidently didn't do the first go-round. This time I intend to work really hard on my patience level and give the solution time to work. Did I already say I...Want...The...Bastards...DEAD?

Sounds like my level of engagement with rats in my garden! I totally get it. I am switching to sand / iavs. I wonder if it is more susceptible than gravel beds.

I think iAVs might be a little more susceptible to RKNs than timed F/D gravel AP beds, but not enough to totally discount the sand systems. I think the only systems that may be somewhat inherently immune to RKNs are the constantly flooded styles of AP because everything stays constantly submerged. But...... for my taste the NFT styles are too limited as to what they are capable of growing. I don't care to be limited to primarily salad ingredients. I much prefer the sand systems abilities to grow practically anything that grows in the ground. I have seen some nice variety from the UVI style, but still not enough to make me entertain that style, plus most every other systems eventually require dedicated filter and mineralization systems and constant nutrient monitoring for optimum performance. In contrast, iAVs once seasoned runs pretty much on cruise control. For some reason I haven't had much success with radishes, garlic, onions and some potatoes. Before I had the RKN invasion I did grow a few pounds of red potatoes. Don't know how, but I'll keep trying till I figure out what I did that was so different. The list of what can be grown in sand is much, much longer than other AP styles.
You won't be disappointed once you get your sandbeds up and running ......... if you can keep the RKNs away. My troubles with RKNs started a few years ago when my FT was just a hole in the ground. I had almost no raised edges around the "puddle", so the heavy rains we had then just washed the RKNs into the FT and the pump sent them on their way to the gravel F/D growbeds I was using at that time.