Replanting and apple; should I worry about replant disease?

A friend of mine convinced me to just replant to replace the Wickson on G11/M111 I killed this summer by painting raw neem on the trunk (as discussed in this thread). While the M111 bottom root of this tree is still living and sent up some shoots, they wouldn’t be big enough to graft to for another year. And they didn’t grow all that much after the first couple weeks, so possibly the M111 roots were weakened by having the top die off in August.

I could try to cleft or bark graft into the M111 in spring, but I’ve never done that before and I do want to get this tree going. The prospect of fooling around with it for another couple years or having my grafts fail or struggle is discouraging. These roots are less than 2 years old, and they were doing fine until August, but they don’t look massively vigorous since then.

So I ordered a new tree from Cummins on G.202, 9/16" caliper. Then reading the currently active thread about topworking (or replacing) big old trees made me think about replant disease.

In my situation, it seems like replant wouldn’t normally be a big deal, with grubbing out a young tree. But it will have spent 8 months with the top dead (though I cut it off), roots living but maybe weakened. G.202 is unfortunately one of the Geneva rootstocks which is not resistant to replant syndrome. So here are my options:

  • dig out old tree next spring, plant new one on G.202 - i.e. don’t worry about replant
  • dig out old tree now, plant new on on G.202 in spring - maybe giving the soil the winter without a tree it would help?
  • figure out a different tree on replant resistant rootstock
  • plant a pear (but I’d rather keep an apple here)

I’m working with a highly constrained space, so it pretty much has to go in the same place. Any opinions?

Thanks for the help!

Replant disease is about long established trees being replaced- the issue doesn’t seem relevant to me in your situation.

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I have replaced recently grubbed trees with no problem. Not gigantic old trees, but young like yours.

Its something like 5-10 years old before you start being concerned with replant disease.

BTW I still didn’t do the neem test on my own G11 trees but next time I get out the neem and paintbrush hopefully I will remember. I have one junk tree I can completely paint since I don’t care if it dies. It still doesn’t make sense to me, I don’t think the dark bark means much as my peach trees have dark bark from where I put neem a year ago but the growth is not affected.

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Cool, thanks for the advice everyone. I’ll just proceed with the replant in spring using my G.202 tree.

@scottfsmith - I’m curious to see what happens with you and the neem; I suspect temp or light was also factor - I did the painting in the absolute hottest week of the year for us, which is end of July. The trees on the east side of the bed get more morning sun, less afternoon sun, and they did not fare as badly. So the ones that suffered were getting baked mid-day and afternoon. Also on one of those trees, the bark on the north side of the G11 chunk survived, while the other 3/4 died. Could be just coincidence though.

I could imagine oil killing a tree as hort oil kills leaves when applied at high temps. Bark would be a lot tougher but hort oil evaporates extremely quickly.

The northernmost side gets pretty much no sun and it seems like a strip there would have survived had the sun been a major factor. @alan, the cambium layer is 1/16-1/8" into a tree that age, I’m not sure how something on the surface could affect the cambium so far in. I do think the neem is the most likely reason, but I don’t get the why.

Yeah, I don’t really get it either as, now that I think about it, my helper has often over applied my axle greaseXmotor oil mix on squirrel baffles to where it ran off onto trunk below without any apparent serious injury, although I don’t think the trees like it. I’m sure some of these apps occur during warm weather.

I just was contributing the idea of oil and heat being a bad mix, but oil injury is usually only discussed in the context of leaves or emerging buds.

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I use a ton of tanglefoot on the trunks of young trees when the rabbits make pests of themselves ( lately). The rabbits all think its an applewood buffet at my house but they won’t touch my pears. The oil base has never hurt my trees as far as I know.

Not sure if your short planting interval will introduce any replant disease issue, but G202 along with many Geneva rootstocks contain a high degree of tolerance to replant disease:

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Oops, I meant my new tree would be on G.222. Thanks for the catch Blueberry. I had looked at the same chart you linked and was surprised to see G.222 listed as “No” in the replant tolerance row. But then must have got confused between then and writing the post. Sorry about that.