Jaboticaba45 thanks for the reply. I just grabbed a Pacific Wax Myrtle for grafting. What have you had the best results with? And what varieties do you grow?
RKN are ubiquitous definitely expect them, especially since trees are coming with soil
RKN are part of healthy soils too, but why potentially create an imbalance that could wreck your soil?
I’ve been buying up hecka tons of rootstock for future grafting
Just so people don’t get confused, RKN is not part of a healthy soil. It is extremely bad for the soil. There are beneficial Nematodes that can be part of a healthy soil but RKN is extremely bad. It’s so bad that some states have restrictions on growers when growing out plants and it’s also one of the reasons that, as far as im aware, that trees usually are to be shipped bare rooted. Plants, especially if shipped with soil make it difficult for USDA to inspect.
I’ve heard of plants being shipped with a red clay type soil that could could potentially hide RKN galls. If one tree in a shipment has galls, I would automatically assume all trees could potentially be infected with RKN.
I do agree with you on that Simon..., but RKN is still going to be there. Small infections of RKN are nearly ubiquitous.
In fact, small amounts of RKN can stimulate plant growth.
But in regular soils it is counteracted with other nematodes and several other factors. The main problem is when they become out of control due to other factors being damaged...They proliferate from the trees in china because it is a warm climate with clay. And I am sure their growing practices are not like ours here.
In fact, most tropical fruit trees we grow are resistant/or don't get damaged to a detrimental extent....Mango, Lychee, Jabos....lots of rootstock we use are RKN resistant like turpentine mango in FL, and many stone fruit stuff. My take is to make sure to have healthy soils and encourage lots of microorganisms to be active.
RKN buries into the roots, so even if trees are bare root, they are still in the roots. And USDA inspected last shipment and knew they were there, but let them pass inspection because they are already here.
Now, just because USDA lets them through doesn't mean I'm gonna plant them out. All my trees are now on cerifera rootstock (including the very nice tree I got from you
). I am with you on that, why put more of them into the ground?
For example, people in Florida grow many cool tropical fruits, but they struggle with figs because they are sensitive to RKN. There is RKN present in Florida sand, but that doesn't hinder the vast majority of other fruit trees planted there. It's a balance that needs to be achieved.
I do believe though, we should be cautious and it is very wise to keep your plants in pots with a container underneath until you can get native rootstock and graft it out.
Most of the info I'm stating came from my soil science class, but I do encourage people to go read the literature and make their own decision.
[/quote]
Hey Jaboticaba45,
I can’t seem to be able to find any articles on RKN actually promoting plant growth in small amounts. I used to do research on plant growth promoting bacteria and mycorrhizal fungi but I’ve never read anything about it helping plants.
Here’s a typical article on RKN in case anyone is not aware of the horrible issues RKN can cause.
https://www.sciencedirect.com/science/article/abs/pii/S0885576524003321[/quote]
plants will produce certain hormones when injured/infected which will increase certain hormones that will encourage root growth like ethylene.
But that is not my main point. My main point is that RKN is everywhere and is present in even healthy soils
and despite them being there, they are not a big problem due to factors of the bacteria, nematode, and fungi interface present in the soil. A gram of healthy soil can have over a billion microorganisms...it is a war zone down there with different species and types of life killing and eating each other.
The horrible effects of RKN like you mention in big agriculture are mostly found in monocrops where basic soil ideas like crop rotation are not in play allowing for a build of of nematodes over time.
Which is not really applicable to the home grower.
As home growers, utilizing cover crops like some brassicas will break down and release compounds that kill RKN. Like I said, I believe the best way to combat them if you do have a major known problem is using a balance by promoting healthy soil, using appropriate roostocks, and introducing beneficial microorganisms like nematodes that eat RKN.
Now I do agree with you it is not wise to plant out potential RKN infested plants coming overseas. The soil microbiome is going to be very different which can cause an imbalance in your soil.
"Root-knot nematodes (RKNs) are ubiquitous parasites with an amazing capacity to interact with a very large variety of plant species."
https://doi.org/10.1016/bs.abr.2015.01.001"Root-knot nematodes pose a significant threat to agricultural production all over the world. They are ubiquitous, polyphagous, sedentary endoparasites and belong to genus, Meloidogyne. These biotrophic pathogens establish and maintain an intimate interaction with their host plants."
https://doi.org/10.1007/s10343-023-00886-5Nice we could have a talk Simon! I admire all that you have done with yangmei.
Best,
Ryan
