AusBonsai

Hi all ,
top day down here in Tassie,so I decided to do some repotting I pulled this crab apple out and found all these lumps over it
last time i repotted it there were a few of these lumps but now there is hardly any roots and all these bulges over it
any ideas
cheers

netanodes?? something like that, cut away the infected roots (if you can) replant in clean soil... the area where that tree was is now infected. some trees survive well with them (my wisteria is covered in them)
http://www.abc.net.au/gardening/stories/s2534493.htm

thanks Paddles
so these can spread to other plants then ? is there a way of sterilizing the infected area?

best I've heard is preventative treatment, although I did read once that you could buy the predator? nematodes, but never found a source... best i've heard is that healthy soil won't support them?? as I said, my way of treating them is to cut them away as much as I can, but as a bonsai, I repot into clean potting mix. I guess you could try sterilising soil, I've heard that you can, there are various myths? old wives tales...

paddles wrote:netanodes?? something like that, cut away the infected roots (if you can) replant in clean soil... the area where that tree was is now infected. some trees survive well with them (my wisteria is covered in them)
http://www.abc.net.au/gardening/stories/s2534493.htm

Hey Paddles, the nodules on your Wisteria roots are not nematodes, they are formed by bacteria that fix nitrogen from the atmosphere.

MattA wrote:

paddles wrote:netanodes?? something like that, cut away the infected roots (if you can) replant in clean soil... the area where that tree was is now infected. some trees survive well with them (my wisteria is covered in them)
http://www.abc.net.au/gardening/stories/s2534493.htm

Hey Paddles, the nodules on your Wisteria roots are not nematodes, they are formed by bacteria that fix nitrogen from the atmosphere.

Oh well, the wisteria is one of the trees I gave away when I first was told I had cancer, so not my problem any more.... lol... Blasted thing never flowered int he 12 yrs I had it anyway....

MattA wrote:
Hey Paddles, the nodules on your Wisteria roots are not nematodes, they are formed by bacteria that fix nitrogen from the atmosphere.

Nah mate, looks like Nematodes to me. only jks

I guess most laymen would assume this was Nematodes, as I believe many basic hort books may lead you to that conclusion.
The cases of Nematodes I have seen, seem to inflame the roots as apposed to cause these nodular groups.

Can you enlighten us Matt as to how one can tell, Nematode attack to the bacteria you mention.?

Rhizobum bacteria nodules form on the roots of legumes (wisteria is a legume along with peas, beans, clover, etc - pea shaped flowers and bean shaped seed pods) The bacteria can take atmospheric nitrogen and turn it into nitrogen compounds which the plant can use. The plant provides sugars to feed the bacteria - win/win - symbiosis.
Rhizobium nodules are pinkish/white and show pink juice when squashed.
Rhizobium is a goodie.

This is a crab apple. Crab apple is not a legume so this is not rhizobium nodules therefore most likely root knot nematodes, also known as eelworms - Meloidogyne spp.
Nematodes are most common in light sandy soils and in glasshouses. Nematodes are baddies.
They are about .5 mm long but cannot be seen with the unaided eye because they are transparent and very thin.
The worm shaped adult males are found in the soil but the pear shaped females are embedded in plant roots. Larvae force their way into root tips and feed causing the production of some very large cells and masses of smaller ones making lumps on the roots as in your photo. damaged roots may be unable to supply nutrients to the plant resulting in a stunted, slow growing plant.
Nematodes may be spread in running water, in soil on shoes and tools or infested plants.
Control:
Nematicides - check with your nursery. Methyl Bromide gas is/was used commercially to sterilise soil (very toxic??)
Some plants kill/ deter nematodes. Marigold is the best known but 'Safer pest Control' by Paul Rogers says that Marigold is not effective against the main species in Aust. Brassicas as green manure are used now.
Quarantine - Don't grow susceptible plants in the soil for a couple of years so the nematodes starve.
Treating soil with solution of sugar and water is reported to work but may have side effects on soil chemistry??
I'd consider getting rid of this plant. at the very least cut all infected roots off and wash off all the soil and burn/ bin roots, soil and pot.

Good luck with the problem.

Thanks for that Shibui.

A very comprehensive answer and good information for us all.

i have never seen such an infestations in my life. Quite amazing.

Grant

Thanks for the heads up shibui,
I will send it to the big bonsai garden in the sky It is not the first to go there nor the last ya got to laugh or you would give up
will keep pot in isolation till i find a way of sterilizing it , bottle of metho and a match
thanks again
jason

the pot is easy to sterilise, give it a good scrub with soap andd water, (DON"T get caught putting it in the dishwasher) then dip/soak in a bleach solution ( I do all my pots in 1 cup bleach to a bucket of water...

In that situation, the match is unnecessary (but fun).

Joel

cheers paddles
the bleach sounds like the go will give it a go on friday but i do agree with Joel it doesnt sound as fun as the metho and match scenario
but it may save some scorched eyebrows

Fortunately I have not seen nematodes like this either Grant. Literature says they are worse in warm areas so not likely to be in Canberra!

Bleach solution described by Paddles is a good steriliser for lots of things. Wash pots to sterilise them. We dip cuttings into the solution for 10 sec then rinse with fresh water to kill any pests before they go to the propagating area. Rinse seed if there's any possibility of pests, etc
I have never washed roots with it but it probably wouldn't hurt the tree - much??

You put bleach in with cut flowers to extend their lives,so a little shouldn't hurt. By the same token what have you got to lose?