Grafting hygiene to avoid parasites etc. on scions

General Fruit Growing
#1

It’s approaching grafting season here (zone 3), and this year is my last chance to keep a particular heirloom apple in the family. I’ve collected a bunch of good-looking scions, and plan to start grafting as soon as the new hosts start pushing leaves and blossoms.

I’m a little bit worried though: the source tree has had issues with oystershell scale and something that looks sort of like a bark fungus. The scions look good, I’ve checked them under a microscope. (Although they do look quite fuzzy, but I’m pretty sure that’s totally normal for apples; everything looks weird under a microscope.)

But I’m wondering – does it make sense to, say, dip them briefly in something like a dilute bleach solution, or dormant oil or something?

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#2

I would dip in 10% bleach solution to kill whatever on the scions surface

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#3

Agreed. Go ahead and dip them as @IL847 says. Also, don’t miss this post by @Jose-Albacete.

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#4

Can you link to that post, please?

#5
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#6

Thanks all, that’s extremely helpful, I really appreciate it!

#7

Thanks for picking up my slack there!

#8

Make sure you update us with how the grafting goes! Good luck!

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#9

Here’s my update: best grafting season ever! I had over 80% success!

  • Good “surgical technique” is important, clean cuts, matching cambium to cambium – but that’s just basic
  • Not grafting until the sap flows works well
  • But Parafilm is the key. And make sure it’s not cheap fake stuff.
    Wrap the scions first, wrap the union liberally, and cover the gaps.
  • NEVER let grafting wax or paste get between the scion and host. I think linseed oil creeps into it too.
  • Structural support is important, but I don’t think it matters that much whether it’s stretchy tape, rubbers or whatever.
  • And take the bindings off before fall, to let the tree do its own protection.

Anyway, that’s what I’ve figured out.

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#10

Congratulations on your success!

I’ll just add that it’s very helpful to have dormant scions - the further along they are (in breaking dormancy) the less time the tree has to callous over and start to feed them, and they can only go a short time on their own.

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#11

Yes, good point. I do harvest scions at least a month or more before grafting, so that the scions are dormant but hosts are vigorous when grafting.

It does help to have thicker scions if possible, but that can be a challenge depending on the source.

I also like your mention that it’s the hosts that form the callus that first bridges the graft.

This time, FWIW, I used the scion disinfection technique with dilute bleach, and didn’t worry about putting anything in with them to maintain humidity in storage.

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