How to treat flowering quince root lesion nematodes

[longd_au]

Hi

How do you treat root lesion nematodes, particularly in flowering quinces?
I repotted my flowering quince today and found at least half a dozen gall looking lumps.

They are similar to Michael Hagedorn's reference on this site. https://crataegus.com/2014/08/02/chojub ... ubai-weak/

I have cut them all out thought might have missed one or two.
Is there an effective nemacides to treat them?

[terryb]

Firstly, if you do have these nematodes infesting your plants, then that is because either the plant was already infested or the soil it was planted in was infested. As they feed they cause the plant cells to collapse causing the lesions that give them their name. These lesions provide the entry point for the Agrobacterium that cause the swellings as explained by the linked site.

Be interested to know if any of the nursery folk on this site know of registered nematicides for home use. There are ways of sterilising the soil but you can't do that with the plant still in it. In field crops, the nematodes are managed not eradicated. Once your plant has Agrobacterium, not sure you can get rid of that either. Sorry.

[TimS]

We use a couple of different things at work, but they are not commercially available through the big green shed or similar. I'll have to look into it to see what is commercially available. Having not had the issue on my quinces i've not had to treat it before.

[treeman]

We use a couple of different things at work, but they are not commercially available through the big green shed or similar. I'll have to look into it to see what is commercially available. Having not had the issue on my quinces i've not had to treat it before.

I would be interested in trying those Tim.
Other than very toxic chems which are now almost unobtainable to home gardeners, RK nematodes like light coarse soils so don't use them for quince, and they dislike regular applications of seaweed extracts. I tried to kill them once by keeping the roots in 50 degree water for 10 minutes. It killed the nematodes..... and the tree as well. .... but IT KILLED THE NEMATODES!

[TimS]

Thanks for the tip about the seaweed Mike, I do believe i mixed a additional sand into my mix for my chojubai to make it less coarse so cross fingers i don't run into the issue.

What we have may not be nematacides specifically, but they will kill nematodes as we use beneficial nematodes to kill fungus gnat larvae so we avoid using them after applying the beneficial nematodes. The one that jumps to mind is a biological larvacide called VectoBac, not sure if it is commercially available though. Looks like choccy milk but stinks to high heaven, the neighbours might complain if people started bandying it about the place. I believe there are others of the extremely toxic variety we have that fall under needing an chemical users permit to use so not suitable for the home gardener. I'll PM you about those Mike, as they are absolutely not going to be relevant to the situation above.

I had a quick look through the ZeroTol that was recommended in the article, the actives are Hydrogen Peroxide and Peroxyacetic Acid, so the answer lies in that direction. Hydrogen Peroxide is at least widely available though how a direct application of it and at what rates would affect roots i have no current answers for!

[terryb]

Other than very toxic chems which are now almost unobtainable to home gardeners, RK nematodes like light coarse soils so don't use them for quince, and they dislike regular applications of seaweed extracts.

This is one of the reasons I dislike common names. The article refers to root lesion nematodes, which I equate with Pratylenchus species, while you have mentioned root knot nematode, which is Meloidogyne sp. Nematodes move best in soil that is at field capacity.

If the issue is simply root knot nematode, a cutting (not root obviously) into uninfested propagation mix will get you a clean plant, albeit a small one. A different kettle of fish if you have a systemic bacterium or virus.

[longd_au]

We use a couple of different things at work, but they are not commercially available through the big green shed or similar. I'll have to look into it to see what is commercially available. Having not had the issue on my quinces i've not had to treat it before.

I would be interested in trying those Tim.
Other than very toxic chems which are now almost unobtainable to home gardeners, RK nematodes like light coarse soils so don't use them for quince, and they dislike regular applications of seaweed extracts. I tried to kill them once by keeping the roots in 50 degree water for 10 minutes. It killed the nematodes..... and the tree as well. .... but IT KILLED THE NEMATODES!

Lol...

[longd_au]

Thanks for all your replies. I have no idea how my plant acquired nematodes. I haven't repotted this quince for several year. It grows in a large pot as a parent plant to all my quince pre-bonsai. This is the first time I've seen such a thing and I am sure you can't miss them when repotting. They don't look pretty and easily catches the hand managing the root ball.

I guess the big question is, will it eventually kill the quince? I've removed all the gall looking lumps.

[treeman]

This is one of the reasons I dislike common names. The article refers to root lesion nematodes, which I equate with Pratylenchus species, while you have mentioned root knot nematode, which is Meloidogyne sp. Nematodes move best in soil that is at field capacity.

If the issue is simply root knot nematode, a cutting (not root obviously) into uninfested propagation mix will get you a clean plant, albeit a small one. A different kettle of fish if you have a systemic bacterium or virus.

Root Knot nematodes are the only serious pest I have encountered on flowering quince (not chojubai though) I fear that Mr Hadgedorn is barking up the wrong nematode?

Lesion...
Symptoms on the roots might include poor root development, root pruning, discoloration and general lack of fine fibrous roots. At early infection stages, brown to black narrow lesions may be visible on the roots

Knot
The root cells around the feeding site are also induced to enlarge and extensively divide thus forming galls

Taking cuttings is hardly the answer if you want to save a 30 year tree.

[terryb]

Root Knot nematodes are the only serious pest I have encountered on flowering quince (not chojubai though) I fear that Mr Hadgedorn is barking up the wrong nematode?

Very likely. I wonder then if Agrobacterium is involved at all or they are simply root knot galls?

Taking cuttings is hardly the answer if you want to save a 30 year tree.

Agree. From your experience is it advisable to bare root any of the flowering quinces (chojubai or otherwise)?